Is steel wool good for cats? Answered

My cat loves steel wool. We stopped buying it because we couldn't keep it away from the cats. I found a box in the basement and was using one to clean metal, she got a hold of it so I put it in the cabinet.  See video below. I got a child lock on the cabinet now but my 2 year old takes them off.  I know I got to clean the kitchen, got folks coming over.

Question by thematthatter   |  last reply


Will burning steel wool to produce Fe(II)O aka iron powder effect the quality of thermite?

Will burning steel wool to produce FeO aka iron powder effect the quality of thermite compared to useing Fe2O3?

Question by Don,t try this at home   |  last reply


Can I use steel wool as a filament for a homemade lightbulb? Answered

I want to use steel wool as a filament for a homemade light bulb.  I would like it to just glow, like a soft red or orange.  Is there a reason why this wouldn't work?  I know tungsten is ideal for a filament but at a lower temperature I can't think of a reason why steel filament shouldn't be alright.  I figure I should pass it by the all knowing Internet first though.  Oh by the way, the steel wool would be enclosed in a vaccuum or in a container filled with inert gas.  I would use this Instructable as a base for my project  https://www.instructables.com/id/Hanging-Bottle-Light-Bulb/  .  Thanks for your help.

Question by cdubnbird   |  last reply


New Wool Stainless Steel Yarn from Lion Brand

Our friends from Lion Brand just sent us some of their new Wool Stainless Steel yarn in shimmery black and gray. Now we need to come up with some great projects to show it off!Here's the what-what:75% Wool25% StainlessSemi-conductive (offers a lot of resistance)Size 0 needles, lace weightWe want to wow them with what we can come up with to use this delicate, ethereal fiber. What would you do with it?Post your ideas, pictures or patterns and we'll get to work!

Topic by scoochmaroo   |  last reply


Equivalent of fire wire. Anybody know of any other easy fireworks (like as easy as firewire to make)?

Just wondering if anybody knows of anything as fun and easy to make. (as easy as the steel wool and wire fire wire thing.)

Question by The Red Button   |  last reply


Cleaning and tinning mild steel tube Answered

I've bought and cut some lengths of mild steel tube to make chimes for a doorbell. Mild steel has a nice ring to it, which is why I bought it instead of aluminium, but it has already started rusting, so I was thinking of tinning the tube before I build the whole thing. My question is mainly how to clean it properly before I tin it. The outside I can do with wire wool but not the inside. I was thinking of just using vinegar to etch away the rust and then give it a good wash before putting it in the tinning solution. Is this likely to work ok? Also any tips on the actual tinning process would be useful. As far as I know you just make up the solution and then put the tube in it for a set amount of time, but I've never done it before, so it would be good to hear from someone who's tried this.

Question by ganglion   |  last reply


Defeating Metal Detectors at Concerts? Answered

I plan to bring a camera to the future concerts of a singer. I believe fans have a right to do so. The camera will be hidden from sight, but I need a way to shield it from any metal detectors that may be used. Using a metal detector designed for coins, I found that steel wool can hide steel items from the detector in ferrous mode. But switching the detector to non-ferrous mode quickly reveals the steel wool. I have found no other material that has any desired effect. Perhaps I could carry something that transmits a jamming signal to the detector. Has anyone here had experience working on this problem and can offer a solution? ~Bob~

Question by ShutterBugger   |  last reply


Heating options for hot bueing steel?

After moving house I am still living in a big mess of boxes that need to be unpacked, kitchen stuff be sorted and and so on... But with a big garage and proper workspace at hand it is also time to consider my options on how to create my tinker space. I would like set up a small forge later on if the landlord gives permission and that means bot blueing steel again. Which brings me to the problem of heating the nitrates :( My last setup was not only on a different continent but also totally oversized and powered by three big gas burners. This time I would like to go a bit smaller so I can use it inside the workshop. Was thinking of a max of around 8kg of nitrates that need to be heated in a safe way to melting point. Problem with that stuff is that it is not only highly corrosive but also requires quite some time and energy to melt. Using gas on such a small scale seems far to dangerous uless I include baffle plates and add several safe guards, so I would like to avoid the open flame approach here. Only reasonabe alternative that comes to my mind is electric heating. Did some small test last night outside :( Used a 2000W electric hotplate and an old stainless steel pot with about 1kg of nitrate in it. After 40 minutes there was still no real melting happening despited the entire thing padded and covered in glass wool. 20 minutes later I turned it all off and once cooled I found that only about 1cm of solid nitrate was at the bottom. If I would use a suitable container of let's say 20x10x10 cm as a small melting vessel: Could it be sufficient to use a 2000W nichrome heating element (with temp controller of course) in an insulated, forge like setup to melt the nitrate ina reasonable amount of time and be able to keep it that way once the steel is dropped in? Problem is the entire garage is already setup with power outlets and they all go to a single 10 amp breaker. I could max it out with 2400W but for obvious reasons would prefer to have some juice left for lights and other uses. If anyone here already made such a thing it would be great to hear how you solved the heating problem without waiting half a day for the stuff to melt.

Question by Downunder35m   |  last reply


Missing Question

I entered a question about if a wired detonator with a 9 volt that is linked to steel wool would burn hot enough/long enought o ingite either aerosol or blackpowder for projects i mess with and it never appeared and idk why. Basicaly my question was..would a 9 volt with 1 wire to each terminal with aligator clip on each wire with a peice of steel wool clipped into each 1 burn hot enough and long enough to ignite aerosol or gunpowder. Idk why my question is missing and im really hoping for a quick answer on my problem and question.

Topic by trf   |  last reply


iron oxide...

Ok, i have been looking through some instructables and everyyone is going to great lengths to get a litle bit of rust by electrolysis). however, burning some steel wool would produce iron oxide? i think i'm right? lol, this would produce black iron oxide is that ok to make thermite with?

Topic by andy60   |  last reply


Is it possible to prevent the chemical reaction that occurs when a tin is boiled in an aluminium pot?

When a tin is boiled in an aluminium pot a chemical reaction takes place that creates a grey film in the pot. This can be removed with some very vigorous scrubbing with steel wool - it takes hours! Can the chemical reaction be prevented or is there another reaction that can be created that will remove the grey film?

Question by dskea   |  last reply


How to Clean a Glass Stove Top?

I have a glass stove top that I cannot get clean.  I have tried oven cleaner, Bon Ami, Ajax, Comet and the run of household cleaners.  I am not concerned about scratching at this point (I tried steel wool!), but want the black burn off!

Question by darlingtom   |  last reply


Two chemistry related questions.?

I have three chemistry questions. 1) What is my result when I mix baking powder(NOT sodium bicarbonate)and vinegar? 2) What is the result when one burns steel wool? Is Iron Oxide my end result? 3) When mixing vinegar and baking soda if I were to keep the mixture under pressure would the water and co2 stay as carbonic acid or still decompose into h2o and co2?

Question by dla888   |  last reply


6v lantern batteries as a power source in a firework ignitor? Answered

Ok so i made my ignitor, and it worked great with the 2 9v batteries when i used steel wool ignitors, however id like to use nichrome ignitors. the 2 9vs just dont do it justice, so i was wondering if anyone thought those huge 6v batteries would work, possibly 2 of them?

Question by G-force777   |  last reply


Fireworks time delay?

I want to set off a few fireworks on the night of my wedding aniversary, and rather than run off and light the fuse, or rely on my dopey brother, I was after a time delay with, say, a watch? So I could set it for 10pm and bamoo.. 10pm we outside enjoying drinks, and a few fireworks go up! I have seen somewhere a guy light a match with a cheap electronic watch using a strand from a ball of steel wool, but I forget exactly what he did and where I saw the video now.. If I could copy that I could use the match to light the fireworks! Any ideas like that would be great.

Question by lochrin   |  last reply


Has anyone made a solar heat powered Fluidyne stirling engine air pump?

So, I will start with what I have in mind.  (Might be total rubbish because I don't fully understand).  You have a solar collector box, not more than 1 meter square.  painted black 1 to 2 cm deep,   and probably with glazing over top. The box itself is metal fully closed up and the back is insulated.  From the box through the insulation there are some metal tubes that go to another box at back for the cooling chamber. Tubes are constricted so the air sprays through to the cooling box and it goes into steel wool as it expands. On the reverse stroke, it does not go so much through the steel wool because the nozel constriction is  on that side not the hot side.   Power is taken away from a liquid piston somewhere attached to both chambers  or a diaphragm at the back. (It can be water cooled). I want the strokes to be long and slow. Can it work?   Temp difference will only be around 40 degrees C and the pumped air ( 2 valves  in chamber off of liquid piston) only needs to go to 2 psi. )    I have been in contact with a guy in Germany who made Sterlings that worked with sun heat.    But he didn't use Fluidyne (also called liquid piston stirling) and he did not pump air.          My specs are extremely low, I only need 60 litres per hour of air at 1 or 2 PSI.  It would be very cool to make it from such basic materials.                 Thanks Brian

Topic by gaiatechnician   |  last reply


The little moonshiner....

Found an old topic that someone reactivated with a reply, so I though I do a new one to make it easier. "Moonshine" can be as tasty as any good spirit from the shops. I have done a few liters back in my days... There are a few things to consider right from the start though. What type of sugar is used, e.g. fruits, corn, wheat, potatoes or plain sugar and water. Equally important is the yeast, some prefer natural fermantation, others use baker's yeast, most prefer dedicated yeasts for wine. Even the water used plays a role in the final taste!Hygine is another thing that many people overlook or neglect. Anything that can grow in a warm and sweet enviroment will grow rapidly! That means if your yeast is not good or fast enough, other cultures can take over and sometimes totally change the outcome and quality. In some cases, like with fruits to the better but usually to the worse. Imagine you want to bake a nice cake with vanilla in it. But since your vanilla stick is already quite old and you stored it together with your garden herbs in one jar.... You get the idea of taste I hope ;) Just go from start to finnish like you would prepare chicken meat together with fish - keep it clean, keep it healthy.The still.... Now, if you trust some old blokes doing moonshine since they were kids then it all sounds so easy. But for the hobby brewer there are now tons of options available. Basic pot stills you can put on your stove, electric ones that are basically just an electric boiler with a cooling tube, tower models with several levels of control or the good old "reflux" still in copper. Why is it important to know your way around stills? Again, if you ask a cook then he will tell you why he uses a certain pot for certain dishes or why he won't work with certain materials. Sometimes it is for taste or ease of handling, often just preference. Lets check the main differences in material. We have the modern stainless steel and the classic copper. Stainless steel is easy to clean, won't affect the taste and won't cause any chemical reactions that would alter the taste of your product. That is true only if you trust the manufacturers ;) To compensate for the problems I will explain in a bit they use all sorts of gadgets. I call them brewing helpers and explain them in a bit. Copper on the other hand is now quite expensive and also deemed to be a pain to clean and sanitise. To be honest: how hard it is to clean a still only depends on the design. If you can seperate it into nice straight pieces with good access you can clean anything. But copper was and still is the prefered option for drinking vessels and cookware in a lot of cultures - and it is coming back into our kitchens now as well. Why is that then? Copper has natural sanitising abilities but also reacts with a lot of chemicals. And since copper is considered to be a "good" metal, these reactions usually happen only directly on the copper. Meaning all reaction products stay on the copper as well. Work with fruits or potatoes and a copper still can look dark black and really ugly when done. Do the same in a steel still and then compare the taste ;) Copper produces a far better taste! Especially sufur based compounds react strongly with the copper but also anything causing bad smells or tastes is reduced big time. To flux, reflux not not to flux at all!? A basic still heats the mesh to a set temperature, a cooling coil or similar lets the steam condensate and the alcohol (and everything else) drips out. More complex models have a more tower like appearance and with that allow for a better temperature control. Here the steam will cool down in the tower and at the right height you have the outlet. Brings a much more refined product. The best is still the reflux still however. Here the steam is allowed to travel further and cool down completely. Only a fraction is allowed to come out while the rest runs back down into the heated pot. From first to last model the quality, taste and purity improve. Lets take a closer look on what actually happens inside a still:Once the mix is hot enough that something can turn into a vapor or gas form it will try to escape. That is why we usually discard the first "head" coming out - it contains the most methanol for starters but also the worst of tastes. Again more on heads and tails later ;)In a simple still all steam produced is now turned back into a liquid.One reason why the alcohol concentrations is quite low, around 40%.But also the reason for the low quality taste that can happen.Even with a generous amount of head removed literally everything that is in the opt ends up in the spirit.A good temperature control is a must have and the less deviation the better.And as with all pots running low, once you are low enough all impurities left in your mesh will be concentrated.If the bottom now gets too hot they release unwanted tastes...We skip the tower models and go right to the reflux as the later is just better and includes all there is to say about the tower models anyway.At least on a hobby level a reflux still already starts with a quite tall boiling vessel.It just allows a better and more evenly heating of the mesh inside.While the bottom part is hotter than the top currents form that constantly mix what is inside.The heat is controlled so there is no real boiling, in the best option so that no part of the pot will go over 85° C.When all is hot enough so the first alcohol could run out the system is actually still closed.All vapour has to run back down the tower - which is why some towers even come with cooling fins...As a result all things with a low boiling point will stay in the tower as vapor and once the still is opened they come out first.The heads can be much smaller then too ;)Since the outlet is set at a suitable height and is naturally cooler than the steam, a lot of steam will condense above the outlet.Much more below it and only a fraction is collected to run to the outlet.That means that once the system has reached stable temps throughout that the tower is filled with ethanol vapour only.And since it is constantly re-boiled and runs back down and up all that comes out is already at quite high concentrations.With a good setup as high as 95% vol.It also means that you can have a great level of control about what exactly ends in your ethanol.Depending on how high the outlet is located a different amount of things that can either bond with ethanol or have a similar boiling temperature will be collected.Sole reason why most simple pot stills are designed to work with sugar and clean water only...When working with fruits as a base you often want quite a lot of the flavours and tastes preserved.Only experience and trying will get you tot he sweet spot where the alcohol content is just right and all wanted flavours are included.Go too high with your quality and the alcohol is too pure, go too low and the taste is bad...Which of course brings us back to why you should take your time before the cooking starts!I know far too many people who have no patience when it comes to the end of fermantation.Some yeast might be still active, far too much sugar left over in the mesh or just not enough care in general...You want most if not all of the sugar gone and used.What is not dead in terms of yeast needs to be dormant due to the alcohol concentration.And that can be the tricky part already!You see, once yeast dies off quickly due to the alcohol only the strong survive.In some cases, especially if you re-use your leftovers often, these few can still be active at over 20% of alcohol volume in the mix.The best option is to have a spare fridge and to put the entire container or drum in there.Let it sit cold for a few days, the yeast goes dormant, all sediments settly down to the bottom as no CO2 is produced anymore.Once all is really nice and clear use a hose or similar to remove the clear content only!Be careful here and once the levels are low use a seperate container to drain off!Take out what you can and if in doubt let what you take settle again for a day or two.Doing this time consuming step will make sure you only boil up what brings you the good stuff.On the other hand, when using potatoes, fruits or such you might have to press the liquid out and and add that to what you drained off already.I prefer to do this first and just put it back into the big drum again to let it all settle together.Ok, you only use sugar anyway but what comes out just does not taste or smell right...Would also mean you only use a basic still...As mentioned before the heads are what contains all the nasties.There are ways to actually measure if there is methanol present but for what we do now this is not so important.When the dripping start use shot glasses or such to catch it.Preferably while watching it ;)Smell what it is the glass when you put the next one under.The first glass should smell quite bad anyways.Quickly the smell in the glasses will change to something more "pure" and alcohol like - now start collecting for use.With a simple but good controlled still you will see the flow increases and levels out at some point.When the volume starts to go down your tails start.It is good practise to now use a seperate collecting vessel for the rest until what comes to fully discard.At some point you will notice the difference between just enough and really good temperature control.In a really good system the flow will go down to a slow drip or even stop.While in a dirt simple one the flow will just slow down for a while and then suddenly start running again.This running happens when the remainig water starts boiling...Keep smelling what comes out and once the taste or smell changes noticably again use a different container to collet what comes out. - This is you first tail collection.What comes out until the smell and taste go bad is your second tail collection - now you can turn your still off for a while.Let all what you collected cool down to room temperature is not already.Check what you collected from the heads, helps to have small jars for this ;)From start to last the smell should get better.If the last two or three collections smeel somehow interesting then add them to your main collection.Smell the first tail collection again - it should not be that bad anymore, especially if you let it cool down slightly open.Especially when working with fruits you might to add quite a bit of this to your main collection.If only sugar was used just move on to the last tail collection.In case you still don't like the smell mix the tail collection together and keep in a seperate and sealed vessel.Those tail collections can then later be used to destill them again (with more tails from other runs) to get a decent cleaning alcohol or something that might still be worth adding in small amounts for a better overall taste.However for sugar only mixes it can be considered to be for cleaning purposes only.What you have now is little waste and a lot of almost good alcohol.It still contains more or less amounts of unwanted things that mainly come from the yeast and their by-products.To "clean" you alcohol the best option is to destill it again - it will also increase the concentration quite a bit.Best option here is to use properly filtered and prefeably demineralised water to get back to a full fill of the still.If your still is quite small and what you collected would make for one or two full fills then go for it.Be warned though that you should not fill it up to the full mark, a bit under is better as the mix now will boil far quicker and more violent.Personally I prefer to have the alcohol conectration in the still at around 205% only.As we already discarded the worst of the worst in the heads during our first run only a tiny amount, like half a shot glass should be too bad in terms of taste and smell.Whatever comes after shall be fine.Again, once the tails start try to be carefull and if you can slow things down a notch.You will see a quite destinct reduction in the flow rate once the tails start - use a new container right away.The alcohol concentration should now drop quickly too as another indicator.If you want just pure tasting alcohol add what you comes out from this point to your tails container for later use as you don't want to drink it.Again, for fruits and potatoes you might want to keep the first bit of the collected tails.You alcohol concentration should now be already over 75% even if a basic still was used.The overall volume you collected will be lower accordingly of course - so don't be too disappointed by the liters you got from the second run.In a perfect world you now would use some nice barrel and let your creation age...But since we do moonshine...There is a chance that even after two runs you still taste and smell things you don't want or like.So if in doubt do it all again and get to 90 or more percent...Either way the final stuff should be now either watered down (filtered and clean of course) to the desired level.How to further improve on the outcome....There are little helpers along the way to get far bette results than without using them.If you check ready to go kits then they often contain specialised yest strains, a carbon mix and some "clearing aids".The yeast part is obvious, although I do prefer life prt wine yeast anyway.Carbon or activated charcoal is used to bind some of the bad odors and tastes the yeast produces.Keep in mind they are designed to work together, unlike using proper wine making cultures.Using power yeasts without carbon always results in a low quality.The clearing aids actually change the acidity levels and cause some things to mineralise or otherwise change so they settle to the ground.But they mainly make sure the yeast is dead.If you only use sugar then these kits are your easiest option and just follow their instructions.For fruits or anything else however you might want to try the slow route and use actual wine making yeasts for a change ;)And of course here we do not use carbon at all as we actually want to keep the taste of waht we use.We already had the proper way of getting the mesh to settle down, so that bit is clear.For sugar only you can now try to run your creation through activated charcaol or just add it and mix it.Let it sit and mix again for a few days.You do not need to filter the black stuff out, just drain it carefully and run the last bit through a coffee filter.Nothing will end in your destilled product.Inside the still you can use ceramic bioling thingies of all sorts.They provide a surface for water or mix to boil on instead of just the bottom.If you can't them for a good price then just use the stuff for aquarium filters ;)As said earlier too, copper is good but most modern stills are made from steel.If you can't find any copper wool pot cleaners you can cut some plumbing pipe into small sections.Inside the boiling vessel they will quickly turn brownish black while collecting bad things.Cleaning is easy with some cirtic acid/delimer/coffee machine cleaner...For a tower or reflux still it really helps to have these copper pads or wool inside for a far greater surface area to aid condensation and slow down the run off.I know how hard it is to get the stuff these days so if no other option use stainless steel ones and only loose the benefit of more cleaning through chemical reactions.Tools that come in handy....Monitoring the sugar and alcohol level to know when the mesh is right is quite obvious.What might not be is that you can correct bad level towards the end of fermentation.Yeast already dying slowly but far too much sugar left? Just add luke warm water to lover the alcohol conectration...Yeast going dormant with low alcohol levels? The sugar might be out so chack and if in doubt add some more.A good stir will help the remaining yeast to get more active in a day or two.So these little glass measuring tools should be put to good use from the start.During the destillation a purpose made overflow pipe to hold your alcohol tester is extremly helpful!The destilled liquid goes in through a pipe or hose at the bottom of the pipe.The bottom is closed, the top open to allow to drop the alcohol tester inside.Overflow or outlet should be just under the rim.During your run you can now see directly how the alcohol content changes.It will stabilse once the heads are finnished and get a slight rise just before it drops during the tails section.Improving basic desing of a basic still...Once you are done with a dead simple pot still and buy a reflux or tower model you might wonder why you did not build one yourself.What looked good on the pics and in the shop turns out to be still a bit away from perfect.The outlet might not have any flow control or is located to low/high.The vital overpressure protection might be missing and the thing sometimes runs out like a garden hose...For the later you can slavage some old pressure cooker and use the weight with the screw in counterpart in the lid ;)A simple hole in the top with flat weight on it works too, I used an old rubber plug from my bathtub one (could not find the purpose made one in time).For the outlet you can cheat a bit ;)Wrapping the tower with some insulating material improves on the heat loss - this helps if the still struggles to heat enough to provide a proper flow rate.Cooling the tower with wet towels, running water or similar well help on hot days or if the outlet is located reall high with little chance to provide decent condensation in the lower parts.How to cheat with the barrel....No matter if you just run with sugar or if you prefern corn, wheat, fruits....For some spirits good taste means good age.And well, good age for commercial spirits usually happens by resting in wooden drums.Oak, white oak, red gum and several other types of wood are used.Some small destilleries even use only locally available wood and won't even tell you which tree it was...Means we have a few chocices if we don't want to stick to the well known classics.But how do we make a barrel ?A good one is not just made from any old wood - the wood needs to be of the right age and moisture.To keep it simple just treat it like your firewood and let it rest for the same time.A good barrel is often "charred" - burnt with a flame or by rolling it with burning charcoal inside.This does two imortant things:1: It provides charcoal to bind remaining bad stuff.2: It releases some sugars from the wood plus resins and othe stuff.Both are an essential part of the final product and aging process!Now it becomes clear why a good sprit cost more than vodka...Using a neutral vessel like glass to age your spirit is one thing, preparing the wood the right way another...You see, size matters here in several ways.Big chunks provide a decent surface are without causing too much debris.The also provide more tannins for the color and more resins and sugar.Smaller chunks provide more charcaol for a higher level or binding impurities.But both will soak up far more alcohol than the correspong barrel size would!Obviously, if you are on a small scale on only got about 5 liters of alcohol to deal with loosing much is bad.The best way to char the wood IMHO is inside a clsed can or steel box.Just a small vent hole and a lot of turning with the right eye for when the wood is charred enough to be black and sealed.Opinions vary here but I use about a cup full of wood per 5 liters of alcohol at around 93% vol.Some goes for the storage, apart from dark some can't really agree here.Tossing and turning is as much prefered as undisturbed resting - take your own pick.The thig I do differently after the filtering off is to re-use the wood that is soaked.It goes into a freezer bag until the next run of the still and then the frozen wood is just added to the second still run to get back the alcohol in it, plus some nice taste and smell :)

Topic by Downunder35m 


Looking for a cheap compressor with a high pressure rating or for airbrush use?

Today a friend of mine asked me if I know a way to reduce the noise level of his compressor in the work shed. With the current heat he prefers to work in the evening and nights, which does not make his neighbours too happy. His main use for several airbrush guns and sometimes for mormal airtools or the big spray gun for an undercoat or similar. So his main concern is oil in the airline and the actual flow rate is of second concern as he has an old 25kg propane cyclinder as an additional air tank. For relative low air volumes I would suggest an old fridge compressor. With a thicker pipe at the outlet that is filled with stainless steel wool most of the oil stays in the compressor. That is if this pipe is a) long enough b) upright c) of sufficient diameter so there is enough for the oil to avoid it being pushed up A second, standard oil seperator will be enough for the oil level required for airbrush stuff - and most other things too. If there is no pressure regulator on the airbrush system it is best to add a small air tank and shut off valve for it. In our case however a fridge compressor would be just enough to keep the bigger airbrush gun running but not to fill the tank at the same time. Not to mention the problem of fluctuating pressure levels. Since we already had a tank and pressure shut off connected to the loud compressor it was only a matter of finding something that keeps the neighbours happy. The first thing we did was to check how often the compressor comes on and how long it runs till the tank is back to pressure. With that and the stated air volume on the compressor we guesstimated that something a bit bigger than the compressor of a window airconditioner should be sufficient. The search begins.... If you don't know what to look for I give you a few hints: Older airconditioners often run on R22 or R12 - both use quite high system pressures which is a bonus, but more on that later. As a rule of thumb for these compressors you cans say: the bigger the higher the flow rate. At the local wreckers and scrap yards we found a few units but noticed the bigger ones often used three phases and not just one :( So we opted for the R22 compressor of a 4.5kW unit. Keep in mind the 4.5kW is for the entire system, so the quite massive fans can be removed from the sum. Usually the compressor alone is the 2.5 - 3kW range. Ok, we found the big thing but how does this help us? First things first ;) The oil was removed as the housing stating the original oil amount. This allowed us to use an oil rated for air use that has little to no water absorption qualities - you don't want water in your compressor. With the usual heat the water should be no problem anyway. Next was a pressure test to make sure the thing actually still works, so we added some plumping in the form of standard connectors to the inlet and outlet. We got well above 200PSI and abondoned the test at this stage as it was more than enough already. The air volume seemd to be well more than expected too so let'S move to the next stage. A fridge or aircon compressor always needs to have a certain amount of oil in it as it will otherwise seize and overheat quickly. But they are also designed so that the oil mixes with the refrigerant to cool all moving parts. So the biggest hurdle is to make sure the oil stays where it should stay and won't enter or get lost in the tank. Only real option for this to use something to catch the oil that is capable of releasing it into the compressor once it shuts off. Now there are several options for this so I start with the most basic: A "catch can" will get most of the oil, especially if filled with stainless steel wool or similar. Downside is that you have to find a way to get it back into the compressor. A step better is a thicker pipe filled with stainless steel wool to catch the oil. If placed upright and the outgoing pipe can be bend a bit upwards you have a good chance that most of the oil will sweep through the valves and get back down into the compressor housing. But only too often the cheap or even free compressor is better than expected and the oil won't get back into the housing as the vlaves are just too good. The last and IMHO best option is a pressurised return system. Most compressors for bigger aircons have a seperate filling port or sealed off piece of pipe. In this case you can do a simple check to see if they are usable for our purposes. Open the port of pipe and use a simple bike bump or similar to get some pressure in it. With a dedicated oil filling port you are best off but they are hard to find. The air you pump in should come out of the high pressure side - you might need a little pressure to overcome the valves. If you hear any bubbling in the housing (use a pipe on your ear or a sensitive microphone) it means you are going through the oil inside the compressor - perfect! You might not hear any bubbling but the port or pipe is still usable. Get ready with your fingers and start the compressor. The fill pipe should be sucking air in, same for the service port if there is one. A dedicated oil port should not suck but instead force some oil up if you cover the high pressure outlet. I assume all is good and no oil is splashing out of the open pipe or port. Add a small amount of oil with a syringe or similar into the port/pipe. If you see an oil mist coming out of the high side it is bad news. Clean outlet air is good. To get the oil back from the catch pipe or can we have to add a hose or pipe with a needle valve. It needs to be adjusted so that there is only a very little airflow (or oil mist) coming out. This regulated outlet is now being connect to the port/pipe with a bit of suction that we found earlier. Now every time the compressor runs the collected oil is forced back into the compressor :) Please double check the port/pipe used is not directly connected to the intake port! The last thing you want is a puddle of oil going into the cylinder and damaging it! They are designed to move gas but not liquid! If in doubt use a hardened sttel nail or similar to create a small puncture in the top of the compressor housing if there is nothing else to use. Check first if the material sound very thick, if so it might help to drill with a 5 or 6mm drill first - only about 1mm to make sure you won't enter the housing and conimate it with metal shavings! Once you have a small puncture hole of about 2mm in diameter get some 2 component metal repair glue mix and add a suitable connection for the collecting pipe/can. If you feel up to it you can of course use a blow torch and solder the connection on. Now we have the compressor working with a oil return system that also gives up very little to no oil at all in our system. You might now think you are good to go but you should at least add a decent and fine filter to the air inlet ;) The compressor noise of a bigger system can still be an issue if thicker pipes are used that allow the noise to travel out. Keep in mind they usually run in a fully closed system.... As we only need to match the noise level of the compressor itself a solid steel can like an old fire extinguisher in the 1kg rage is a good way out. Fill it with filter wool and a fine filter pad after adding some hose connectors either end. You can misuse the trigger nozzle and keep it to seal the top if you braze a connector on it. If the intake here is about 5 times larger than the pipe connection to the compressor itself the air flow going into the thing is low enough for a cheap paper air filter can or box if you have a quite dusty enviroment to work with. The real trick is to have a hose or pipe on the inside of the fire extinguisher connected to the compressor pipe connection. A garden hose is great here as is reduces the noise quite good and is dirt cheap. Make a lot of about 2mm sized holes in this pipe and close the other end of it off. Now the compressor will suck it through the small holes and the soft garden hose reduces the noise, the surrounding padding brings it down to basically nothing. The special case of clean air for airbrush.... If you read this for the sole purpose of airbrush use then this chapter is just for you, all other might want to skip it. The two things you don't want to enter your gun is oil or water. Both are a common thing in normal compressors due to lubrication and pressure difference resulting in condensation of the humidity in the intake air. Oil free compressors of good quality can cost quite a few bucks and often require ongoing replacement of membranes or piston seals. A refrigeration compressor with the above modifications already provides clean enough air for most airbrush users if a proper tank is used to store enough of the compressed air. So you might just want to add a basic oil filter or very fine paper filter close to the regulator. For very detailed work with very sensitive paints you might want to build a filter box containing of several layers of oil absorbent paper. This stuff is often used in the industry to clean up minor oil spills and bind oil very well. A PVC pipe (pressure rated please) with 5-8 layers of filter screens should last about a lifetime before the filters need changing if the diameter is in the 10-15cm range. That leaves us with the dreaded problem of condensation and water contamination. Depending on the type of paint and gun used a small amount of water vapour is usually no problem. Solvent based paints usally show their disliking by unwanted drops or run offs caused by water droplets. Of course you just go and buy a professional dehumidifier and accept the ongoing replacement costs for the cartridges... But if you are in a climated that has above 30% humidity for most of the year than you will have to remove the water one way or the other. A big enough storage tank for the air that is upright usually helps to release any condensated water prior to usage. But if you use a homemade tank you might want to avoid this problem completely and forget about water in the system altogehter. Silaca gel is the answer here, specifically the indicating variety that changes color once "full". A spaghetti glas or similar should be big enough unless you are in a very humid climate - is so just use multiple in a row. The air intake side for the compressor has to go through the silica gel to be effictive. This mean we need two holes in the lid. One with a pipe or hose going all the way to the botom - that is the air intake side. The other right on the lid - this is the air outlet side which continues to the compressor intake. With the color change in the silica gel we can estimate how much usage we have left until we have to heat it up to remove the water. If this color change happens quite fast from the bottom to the top, let's say within three days or less than you really need to use more jars with silica gel in a row or a longer one - like using a long and clear acrylic pipe instead. Of course you can always just cut holes and "viewing glasses" along the length to a PVC pipe.... No matter how wet your climate is you want to get at least 100 hours of compressor run time before you need to recharge the silica gel. This brings us to the recharging.... Once the color changes and you only have about one quarter left to the top you want to get the water out of the gel and re-use it. To do this you simply heat it up in your oven to around 120-150°C - the supplier should state the max temp for this. If you use a gas oven or one with limited accuracy here it is best to stay within the 120° range. You need to stir and mix the gel or use something big enough like an oven tray. But be aware that these little balls are like glass! The roll and bounce like no tomorrow! IMHO it best to use an old cooking pot that has no plastic handles for this and not to overfill it. This allows for easy mixing without making a mess that might cause a bad trpping hazard on your kitchen floor tiles! Once the gel is back to original colr it is time to let it cool of to a safe temperature and to fill it back into our canister or pipe. Tanks and shut off systems.... We have a refrigeration compressor working for us, and since it was for R22 we can use much higher pressures as a simple compressor from the hardware store. The low pressure side is used to 70PSI or around 5Bar of pressure in normal working conditions. The high side often works at pressure in the range of 200-300PSI or 14-20Bar! The tank we used is a big propane tank that was restamped at some stage in his life for the use of LPG - so it was tested to quite high pressures. The lower pressure limit is what keeps the stored gas liquid at the given temperature. For Propane at an imaginary 30°C this would around 155PSI or 10Bar. The stamped test pressure, although outdated, showed 600PSI or around 40Bar of pressure with no problems - and the thing was thick in the walls... The old shut off switch from an old air compressor was adjustable after removing the safety cap with a bit of force and the help of few cold beer. With a little tank attached we adjusted it to turn the compressor off at 250PSI or around 17Bar of pressure. If your tank is old or has no test pressure stamped on do your own test in a safe location. Make sure the area is secured so there is no chance of debris from a brusting tank can go anywhere - this includes to chain down the tank itself ;) Use the aircon compressor to fill it up to 300PSI or 20Bar of pressure - this should be tolerated with ease by any propane or LPG tank. Shut the valves and let it rest for a day or so. It is best to do this in the early morning so the heat from the day will slightly increase the pressure. At the end you still want to have a working tank and no major pressure losses. All of our mods on this tank were done without actually harming the tank. This was possible as the original valve had a release port for filling purposes - as it standard on most refillable ones. Here we removed the valve and added a pressure guage instead - better to know what is happening than to assume things. As this "port" had a seperate connection to the bottom of the brass valve we added as T-connection to allow for the connection to the compressor. Just be be really sure a thin piece of copper tubing was brazed to the exit hole of this port so all incoming air will be going down and away from the outlet connection with the big shut off valve on top - which we use to actually isolate and close the tank when not it use. Last thing required was something to connect the pressure shut off switch and regulator to. That was the only major expense on this project as we had no old BBQ hose or similar to get a suitable connector to the tank. We bought a simple adapter for the use of smaller hoses and cut the unwanted bits off we there was only the bottle conntector with the nut left. After removing the rubber ring we brazed piece of copper pipe onto it. Here we drilled holes and fitted severy connectors. First for the pressure switch, then for the connection to the pressure regulator and two standard ones with a ball valve for air hose connections. One air hose connection female, the other male so a standard compressor can be connected as well or "backfilled" for additional and mobile storage use. As we wanted to avoid any reduction in the safety and burst pressure no release valve was added at the bottom on the tank. The added silica gel filter stage was used instead so no water will get into the system to begin with. Additionally, and painfully for me and me friend, the inside of the tank was coated with a layer of acrylic paint to prevent and rust as it was free from it when we checked it at the beginning. This involved filling a suitable amount of paint into it, closing the top while keeping the thread clean and then to move the tank around to cover the inside evenly. If you do this be prepared for some weird movements with your friends LOL Once we were sure all ust be covered by paint at least three times we released the exxess paint and allowed the inside to dry with the assistance of some air forced to go in with a length of pipe. This was repeated 3 times... Then another two just for the bottom third of it where there might be some moisture after all... Now you don't want to remove the brass valve with everything connected to it just to turn the tank over to releae the collected water. Instead we made sure the added pipe on the former relese port would go all the way to the bottom of the tank. If any water collection is suspected only the connection to the compressor needs an additional valve for the disconnection so the water will be force back out here. To make this easy and fast we used standard quick connectors and a piece of flexible airhose rated to 20bar of pressure for the connection to the compressor. We checked the performance of the moisture removal and oil removal only for a few hours of running time while priming some surface for later use. The compressor oil used was very smelly to say it nice but nothing coul be smelled in the first paper filter after the pressure regulator. To check for remaining moisture levels (65% humidity in the house) we used a 10m length of clear PVC tubing going through an ice bath. After 30 minutes of moderate air release there was no condensation on the inside of the tubing visible. Of course if you only need it for air supply and don't care about a bit of moisture and oil you can keep it simple ;) Benefits of doing such a stupid thing: For starters noise and the peace of mind that you can do a lot of airbrushing until the compressor needs to kick in again. Then of course the benefit of an almost silent system compared to a standard compressor - something you can actually tolerate while doing art. But the real deal is knowing YOU did it and you did it for cheap. Warnings and some advise... I know, it should be at the very beginning but I just hope you read till the end ;) If the compressor fails from overheating you are up for a new one. This means the tan size should be within the limits of what the compressor can handle - same for what you actually use on air. You want an empty tank to be filled before the compressor feels hot to touch - quite warm is fine but if you can't leave your hand on it then it is too hot. Same story for the usage. There is no point in using a tiny 10 liter storage tank if you need that capacity every few minutes. The compressor would only have little pauses and overheat quickly. You want a good balance of usage time before the tank goes below supply pressure and running time of the compressor to get it to full pressure again. This brings us to the safety of high pressures. Where possible only copper tubing or sufficiently rate hoses should be used, the later as short as possible to avoid them acting like a whip if something goes wrong. When it comes to the safety of the tank you want to make sure to stay withing it's rated limits. All benefits of a compressor capable of producing over 500PSI otr close to 35Bar is wasted if your tank and pressure regulator can't handle it. This must not mean that you try to use a gas cylinder of unknow age and pressure rating and assume it will work! If in doubt use a lower shut off pressure and stay within the limits of normal air compressors - which is around 120PSI or 8Bar. Never, ever use a tank that is compromised by inside rust or bad corrosion on the outside! If you don't know how to braze copper tubing, pipes and connectors then check out some of the great Instructables about it! Whenever you know you won't use any compressed air for more than a few hours close all valves especially the ones going back to the compressor on the high pressure side! Some compressors really don't like a huge pressure difference constantly pushing on the reed valves. If your tank is big enough to allow for more than one hour of operation before the compressor has to top it up you might want to consider a one way valve right on the compressor outlet. This will prevent any massive pressures going onto the valves - especially helpful for modern compressors that only rely on the sealing capabilities of the clyinders or rotary system used. One thing you should always consider is a pressure relief valve rated for about 50PSI more than your tank pressure - it can be added to the pipe ;) If the shut off valve ever fails the relief valve gives you the ease of mind that it will blow before your tank does. Maintenance... If modded correctly the compressor should stay in the compressor and the compressor itself should not overheat from use. Having said that your compressor might force out a little more than your best catch system can handle. If that becomes a problem it might help to use an oil with a lower viscosity. If all fails it just means you need to top up oil once the last last paper filter is filthy or use slightly more to begin with so the intervals are longer. The silica gel, if used should be recharged before all of it is wasted - no point in adding it if you use it once full of water. If no gel is used there will be water in the storage tank. Even with the added paint and a good air filter it is possible that nasty things grow in there. Making sure the tank is emptied of any water after long uses and again before the next use is good practise. If no pressure gauge is used on the tank you must make sure the shut off valve is always working fine and within set parameters. I strongly recommend using a gauge and if not to perform a pressure check of the system every now and then to confirm all is within parameters of normal operation. A compressor constantly running means you either use far too much air or you have a leak - same story if the compressos kicks in after some of forgetting to shut it off and close the valves. If you keep the above in mind the salvaged compressor should work just fine for many years to come. Troubleshooting and alternatives.... You put everything together the right way, double checked and something is till not right? Maybe my crystal ball helps me to find something... 1. Always oil coming through the catch system. It usually means you use too much of it. A salvaged compressor, if the refrigent was removed legally from the system should still have a "correct" level of oil inside. Too much oil would mean is being pumped through the system at an excessive rate. Very thin compressor oils tend to do that in the compressor is misude like we do. Changing to standard mineral oil can help here. As a last resort you can use a pressure gauge or good judgement to allow more flow through the needle valve from the catch system back to the compressor. Too much backflow here would mean we loose system pressure to the set level of this needle valve! 2. The R22 rated compressor seems to be unable to produce enough pressure. First do a leak test using soapy water to rule out any leaks. Do a back pressure test on the ports. If you can push air through them in the reverse way with ease it means the valves are damaged making the compressor useless. You need to replace it. A regular cause with our type of usage is a constand back pressure from the storage tank to the compressor. To prevent this it might help to mount an electric solenoid between the compressor and storage tank. Such valve should be off when the pressure switch is engaged and on when the pressure switch is disengaged. This prevents the coil from overheating but requires a "normally off" type of valve. A good source at the wreckers are cars with LPG systems installed, they usually have suitable 12V valves somewhere on or near the tank and filler cap. 3. I am using several kg of silica gel but still get a lot of water in my storage tank. Going overboard in a humid climate can be a good thing here but if moisture makes it into the tank even with great amounts of silica gel there are only two causes: a) the tube or cylinder used is not long enough or not wide enough to allow the absorption of all the moisture going through. b) the flow rate is too high and the temperatures are too. For the first the solution is obvious enough. The second is related to the first for the diameter and lenght but temperatures constantly above the 30°C while operating somehow limits what the gel can do. Using a cooling coil on the intake side or simply putting the gel containers in icy water will help to a great deal here. If that is not an option than I suggest to layer the gel and to seperate it with fine paper filter screens. This will slow and even out the airflow allowing for more contact time with the gel. 4. The compressor gets very noisy after some time. If "some time" means more than 30-45 minutes you simply have it running too much and it overheats. If the noise increases too much when reaching the shut off pressure it can mean the pressure is too high for it. 5. Can I use multiple compressors from smaller units or refrigerators to get enough air volume? Of course you can but it might mean you have to lower your pressure expectations. Consider that each individual compressor would get the back pressure from all other compressors running while it's outlet valve is closed. To avoid premature failure you want to make sure the compressors are shut off at a lowver pressure. 6. I don't want to use a big tank but require a good airflow for airbrush. Two or three fridge compressors working one after the other with a small tank to keep the output pressure even can allow for about 30 minutes runtime per compressor. With three it gives one hour for the the first to cool off and should be enough for ongoing work. Downside is you need to make some sort of automatic switch to "rotate" to compressor working. Last words.... Is you find any spelling mistakes you can keep them. However, if you use them in any way to make a profit with them I kindly ask for 10% of your earning from it ;) Why did I not make an Instructable out of all this? Well the day was very hot, the beer very cold and my mobile phone at home, so I did not take any pics. To top it up the whole thing is now in a seperate box for additional noise reduction so it can be used in the same room where the guy is working. Of course he just used a nailgun for the job without any regard of access or at least easy view of the two pressure gauges. Typical if you have a great idea and the cold beer tells you to forget all about screws or hinges ROFL Only comment was: You created it and it works fine, why would need more than the pipe connections for the gel and regulator? Maybe he will reconsider when the service is due....

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