can compressed gas leak through a metal tank? Answered

So the other day i was talking with my friend and  he told me that gas can leak out of a metal tank.  he said gas can leak out of scuba tank going through the metal just like it goes through a latex balloon.  so i wanna know is this true?  could gas leak out (given enough time) through a 12 gram CO2 tank used for airsoft for instance?

Question by cdubnbird 8 years ago  |  last reply 8 years ago


how do i repair a leaking gas tank without welding it?

no one makes the tank for my motorhome anymore and i do not have welding tools.so how do i fix this?

Question by twighahn 8 years ago  |  last reply 4 months ago


Help!! It's 3am and I have a bubbling and squeaking battery!

Please help! I procured an electric wheelchair today (worn and torn, but in good shape.  It had 2 12v batteries, little smaller than an auto batt.  Didn't write down the amperage tho...The batteries were visually inspected for bowed or expanded sides, cracks, oxidation.  Everything appeared in order.  They have likely been sitting for some time.  Stupidly, I did not check electrolyte levels.  Oops.  Could easily be low.  I plugged the charger into the mainboard for 30 minutes, watching closely.  No issues, no overheating.  I left it for another 2 hours.  Again, no noticeable issues.  I tested the drive motors by controlling it around my driveway briefly. Power was very low.  It worked, but clearly lacked juice. I plugged the batts in for another 4 or 5 hours.  But after that time, I noticed a crackling/squealing (faint) sound.  As if pressure was escaping.  Bad news.  I had the chair chassis (and batts) in my workshop, and now I was afraid it may blow, contaminating everything.  The batteries feel warm. One more than the other. Beginning to panic, I threw on my goretex, respirator, goggles and gloves and carefully detached the battery cable from the main board.   I've never had one of this size blow, and have no idea what it could do.  very hesitantly, I rolled it into my garage, and closed the door.  Now I'm afraid to sleep, because I'm concerned about it. Is this Normal old battery behavior?  Could this be due to low electrolytes?  A small crack in the case?  Is there anything I can do besides wait?  I'm not real anxious to go too close for too long.  Is there anything I can do that would not increase hazard?  I'm about to throw a tarp over it, but is there a high flammability risk if a high amperage 12v were to blow? Guidance highly appreciated.  Thank you.

Topic by huck alexander 6 years ago  |  last reply 6 years ago


which valve to use for storing gas in bottles?

I need to store gases(mainly hydrogen, generated from electrolysis)  in a bottle. I was thinking of getting a bicycle valve and attaching it to the bottle. The problem is I cannot find a bicycle valve anywhere online. Moreover, when a bicycle valve is opened the inside gas leaks out. Is their anyway of storing a gas in a (soda or soft drink) bottle? Which air valve should I use?

Question by dark32 3 years ago  |  last reply 3 years ago


Mystery of the CO2 Balloons!

Filled some balloons w  co2  from dry ice in a soda bottle.   As expected, they act like a lens, a magnifier of sound. No mystery there. Just as a dense glass refracts light, the denser gas refracts sound. The mystery is why balloons filled with co2  leak down faster than identical balloons filled by mouth. Yes, there is some co2 in my exhaled breath, but it is mostly  n2,  and  o2.  I would hav expected the n2 and o2 to leak out more quickly, being smaller molecules. So whatzup wit dat?

Topic by Toga_Dan 4 years ago  |  last reply 4 years ago


How to prevent gasoline fumes from seeping into my house/garage from a neightbours garage?

Hi all, Back again with another issue regarding the money pit. I live in a townhouse and my neighbours have two motorcycles in their garage. They leak gas and I am guessing pretty badly because I cam smell it in my home. When their garage hasn't been opened in awhile it's fine, but when it opens, I am supposing the pressure builds up and BLAMO It comes through the vents in the house or around the vents in the house. My garage even smells strong of gasoline and I have nothing in it that uses gas. Is there anything I can do? Besides to obvious and talk to the neighbours, and the condo corp, two things I have already done. It wasn't bad in the summer because they were in and out and the windows were open so there was less pressure, however, when I arrived home last night it smelled like a flippin gas station in there! I am waiting to hear from the condo corp, trying to be proactive because clearly this issue isn't one they are tending to with immediacy

Question by sherie 7 years ago  |  last reply 7 years ago


After puncture in the freezer, the cylinder on the back underneath water tray is hot

I was deicing freezer in the refrigerator and accidentally puncture. Gas went out for a few seconds. The refrigerator has topped working. When I cleaned the back and trowed away accumulating water, the cylinder beneath is still hot. Any possibilities or repair?

Question by Sharing Fun with WiSH & EmmaS 1 year ago  |  last reply 1 year ago


How do I fix my Nitro car rc tank?

My RC tank has a 1 inch crack were the fuel line attaches.  It leaks faster than the engine can demand it.  I can't seem to fix it i've tried 3 things like: taking a soldering iron and running it over the crack didn't work, Hot glue over crack-didn't work, teflon tape around it the kind with the adhesive on it.  All of those things the Nitro fuel de-solved it in about 10 hours. I am running 20% nitro.  I have already ordered a new tank on eBay. it's just I need it fixed by friday for a race.  The new gas tank hasn't been shipped yet it is coming from Pennsylvania I live in Utah also shipped USPS parcel post please help!! if there is a product out there or any thing that will work. Thanks

Question by ebayboy98 7 years ago  |  last reply 7 years ago


Overfilled SLA (lead acid) help!

What should i do its just leaking gas (I assume its hydrogen) should i keep chargeing till this stops or what? thanks for helping

Question by Daniel Deacon 7 years ago  |  last reply 7 years ago


mice in motorhome

We have a Motorhome istored in a shed and are forever getting Mice in it. We have searched many times trying to find any hole they could be getting in , but without success.   If we could fill the vehicle with water & then see where it leaked out it would work but destroy the vehicle!!! Is there any coloured gas for example, we could put in & put it under pressure to see where it leaked out, or light a smoky fire underneath it & put the interior under vacuum.   Any ideas greatly appreciated. Lyn  

Topic by mcflin 5 years ago  |  last reply 4 years ago


water heater popoff valve?

I am trying to replace a popoff valve on my gas water heater, the heater is about 10 yrs old and is leaking at the plastic valve on the top where the water supply comes in. I have found a replacement but not sure how to get the old off and the new on?

Question by kayneed 7 years ago  |  last reply 7 years ago


What is wrong with my carburetor? Answered

AENL wisconsin motor 9.2 hp. 163e Zenith Carburetor. Everything has been rebuilt. I did most of the work myself. I started it for the first time, it fired right up. Then stopped after a minute. I noticed it was flooding...badly. fuel was leaking out of the carburetor by the intake. I then pulled the cord a couple more times and now it is leaking gas through the exhaust port. What happened? Float to high? I set it to the gauge provide by the carb kit. It was pretty close to right on. What next?

Question by oil_derrick 7 years ago  |  last reply 10 months ago


How to i build a room under my shed so that is wont cave in during the winter or leak etc?

Okay, so i have about 18 by 18 are that i can dig in and i really am not familiar with where my water and gas pipes are. (i also am not sure about electric wires) so any help on that would also help. this is in my back yard if that helps at all also. i really don't know much about how to support it as i build and also how to reinforce it. so let me know what you think. anything else that you need to know so you could help me out just ask and id be happy to answer.

Question by ctitus 7 years ago  |  last reply 7 years ago


Has anyone ever used or repaired a SplatMaster marking pistol?

 Hello, This is a long shot but has anyone here had experience with SplatMasters? I bought two of these guns about 15 years ago, second-hand and they have never worked. They dry fire perfectly but the problem comes when I load a CO2 bottle; it leaks. Is this a known fault and can it be remedied? The bottle is punctured on the spike, as it should, then proceeds to hiss and empty immediately. There was nothing around the spike when I bought them so I tried various items ranging from inner tube to gas o-rings, until I ran out of expensive CO2 bottles. It may be possible that the gas is seeping from another part of the gun; Any ideas? Also, according to the photo with the red background I can see that every part seems to be there except a small spring and a ball detent;  Can I simply make one from a pen spring and a ball bearing? Any help appreciated as I would dearly love to have fun with these. Thank You

Question by FriendOfHumanity 9 years ago  |  last reply 6 years ago


How can i convert the side windows in my truck shell to be side doors? More in details...?

I have an Innovation truck shell, it is a discontinued brand (came with my truck when i bought it) so no truck shell people want to work on it (a lot of them seem to have the policy that they won't work on shells they didn't install. My original plan was to find and have installed windoors, then have aluminum water jet cut to either cover or replace the glass if i couldn't just get them premade as metal or fiberglass doors. There was a video from germany that had the installation of what i was looking for, but nothing local, and i couldn't find them to buy doors. i am concerned if i can't find them and go to my secondary plan, to piano hinge and attempt to gas shock my waterjetted pieces and fabricate doors to fit in the frames, will leak and not work well, the frames aren't made for that kind of movement and may fail. i know i will probably have to cut my shell if there aren't indoors that fit my window holes. not sure where to start or go with this, any advice or strategy by  a knowledgeable person appreciated, Thanks!- Subconscionaut

Question by Subconscionaut 1 year ago  |  last reply 1 year ago


Homica - The remote-controlled 'smart house' using Arduino, iPhone and Apple Watch

Homica is a project that thanks to a smart web platform allows to control in a remote way (using an iPhone and Apple Watch) sensors and actuators installed on the Arduino boards. Homica not only allows to monitor our home in all its aspects through a multitude of sensors but also to perform actions on the whole installed actuators. Moreover, Homica is able to execute actions as results of events. This logic will be called "Homica Profile". Below there are just few examples of "Homica Profiles" that can be created using Homica. If we are not at home and we want that the acustic alarm is activated and all the lights goes on and an email is sent when a motion sensor detect the presence of someone in the house. If our garden has an humidity below a certain value, then we have to water it until the soil humidity will be a specific value. If we want to be notified by email if there is a gas leak. If we want that a number of lights goes on if we clap our hands once and we want to turn them off if we claps twice. If we want that all the lights or some goes on or off with a simple action. If we want that some lights goes on if a motion sensor detects a motion. If we want that some lights goes on when night comes and off when becomes day. If we want that an electric kettle and some lights goes on at a specific hour The most interesting aspect is that we can create all the profiles we need directly using the iPhone application called "Homica Remote" without any Hardware changes.   Complete Project Video https://youtu.be/s520dv2i9Rg Remote controlled by an Apple Watch Video https://youtu.be/ZwCsdlMXShk Remote controlled by voice (Speech Recognizer) https://youtu.be/ixZyjLN6izU

Topic by MicheleC5 3 years ago  |  last reply 3 years ago


Create Scholarship Entry: Hearing Impaired

My project is designed to solve a personal problem. One I'm sure others struggle with. I am hard of hearing.My proposed project is for the iRobot to find me and tell me, via an LCD screen or similar visual, that the phone or doorbell is ringing. In order to keep the search path short, to start, in my house I'm thinking about using either virtual wall, which I can't afford, or a line down the hallway to the bed. When something is out of focus you can frequently stare at it until it comes into focus or you can ask someone what the sign says. With hearing loss you eventually realize you don't know you didn't hear something because people start yelling at you for ignoring them. Sound is fleeting. Usually only lasts a fraction of a second. I hear less that half of what most people hear. Without my hearing aids I can only hear the noisiest birds if they are about 20 feet or less from me. I can only hear my phone ring if I am within 15 feet of it and I have the volume all the way up. To talk on the phone, I have one that is relatively new and have the volume all the way up. Those 90db alarms, I need to be within 5 feet of them to hear them. The smoke alarm in the kitchen, I can hear it but it isn't going to wake me. A fire in the kitchen isn't going to trigger the alarm in the bedroom soon enough. It probably won't be loud enough to wake me, anyway.My house didn't have a doorbell when I moved in and I can't hear someone knock unless I have my hearing aids on and am within 10 feet of the door. After missing numerous UPS deliveries I installed a wireless doorbell and I carry the receiver, pager style, with me all day when I am expecting a delivery. And I have even missed UPS with that. If the water is running, the TV or radio is on, it is even more likely that I will not hear the phone or doorbell. If I'm in the bathroom even with the door open I don't have any idea what is happening on the other side of the doorway.A security system with cameras and sensors and a DVR would be ideal. But not in my budget. It might help me with my thieving neighbors.I have thought about getting a dog to help me but I have three rabbits and cannot afford another pet on my disability income. That would probably be a good solution. I own my own home, ok the bank owns it and lets me live here, but if I have to move into a rental most landlords do not allow pets. A robot would not be an issue.If I had a robot that could find me and let me know what is going on in my house it would be very useful. People do not wear hearing aids to bed. I don't usually wear my hearing aids at home to save on batteries. And because the feedback drives me crazy. I just turn the TV or radio up REALLY, REALLY LOUD. Sorry neighbors, it's not my intent to be annoying.I custom built the computer I am using. I have some experience programming simple robots such as the Parallax Boe-Bot. Most recently I built the miniPOV and mintyBoost from AdaFruit. I have 6 years experience as UNIX sysadmin and configuration management. I also have basic hardware and soldering experience. If I have enough time I would like to have it bring me the phone and have a microphone and speaker to talk to the person at the door. I would definitely like to add smoke and co2 detection but I noticed there are quite a few people taking that on and so I will leave that to the end. Maybe teach it to do a little dance, sing a little song, get down tonite. I could wrap it in mirrors, turn it into a floor disco ball. A different dance and sounds for each alert.A robot that could notify me of doorbell and phone events would make my life easier. I'd be inclined to sleep with it. If it could help clean up after the rabbits and ride herd on them I might worship it. Rosie the Robot, Rabbit Wrangler and goddess. If it could also keep me safe from intruders, fires, gas leaks and such. Heck I'll bear it's child! Shall I name it Proteus? or Alfred? Have you ever seen the movie Demon Seed? Classic.I took my time writing up my proposal to do some research and make sure I have the necessary skills and resources to accomplish this task. They warned us in the challenge. I also wanted to have something unique, although there can be many approaches to solving the same problem. If I do win one of the scholarships I will be interested in your suggestions about how to solve this project.

Topic by SacTownSue 11 years ago  |  last reply 11 years ago


The best car ad ever made

A family member sent me this ad that was posted on craigslist, while it was the most explicit ad I've ever seen, I'd prefer this over any normal ad. Enjoy those who feel comfortable reading this. DISCLAIMER:  I bleeped (****) out any explicit words...... Though I could have missed s-something.  And explicit's definition is different between people Side note: If anyone thinks this is a tad (or more than a tad) over the top, PM me or reply saying so. I'll delete it. - - - If you think you'll be offended by this ad... DON'T READ IT.  - - - - - - - - - - - - - - - - - - - - - - POS 1994 Honda Civic LX for sale - $600 (Marietta, GA) Date: 2010-07-11, 4:49PM EDT Reply to: sale-63pgj-1837513434@craigslist.org [Errors when replying to ads?] That's right, you can own a piece of shi... history right now for only $600. You may wonder why I didn't post a picture and that's because with a car this crappy, a photo is not needed. Just imagine the worst possible car and then picture a camel taking a dump in the trunk and you'll have a close approximation. You don't need to worry about me lying... it really is a POS. There is no risk of you getting over here and finding out it's really a gorgeous gem worth thousands... that doesn't happen...ever. But if for some reason that's actually happened to you, then you are acquainted with a crazy cosmic karma that has never thought to even piss in my face. I almost had a date on PlentyofFish and you know what happened? The f***ing AC died. For two years while I was not dating, it worked fine. The day after I get digits, the AC craps out. The car also has a weird hesitation problem that was not fixed even when I replaced the fuel filter. What could cause all of these things? Satan in the drive train...that's right... it's rare, but it happens to guys like me. This car is actually demon-possessed so you can forget about any sort of easy fix. Jesus said you need faith to cast out demons like this and believe me there are only two people on the planet that have that sort of faith. One guy lives in a cave in India and the other guy is dead. And you can forget about the guy in the cave helping you because, if you can find him, he's just going to tell you how physical setbacks are really spiritual blessings...blah blah blah...yada yada yada. Exactly. Don't expect sympathy from any motherf***er that sits around in his underwear in a cave. Other problems with this car include busted boots on the tie-rod ends, busted wheel hub boots, broken AC, leaking power steering system, ABS light always on, check-engine light comes on occasionally, driver window sometimes comes off the track, paint has permanent dirt in it (yes, it's f***ing permanent...you can't scrub it out with anything less than sandpaper or some highly explosive chemical that causes cancer in 49 states and erectile dysfunction in the 50th.) The car does drive, but that's about all it's good for. Good luck getting it to pass emissions. I've never tried as it's still registered in Clarke County. If you want to date, this car is probably not for you. On a positive note though, I can assure you no one has ever had sex in it. It would take a miracle to get a girl to even sit in this car, much less take her clothes off in it. Other possible uses for this car included entertainment at frat parties. You could charge people $5 a swing with a baseball bat, although you still probably wouldn't recover your investment. You might be able to sell it to the Mythbusters and get the to test the myth, "Is it possible that a car could really be this s***ty?" Adam Savage and Kari Byron will have a field day and close it off with "Myth f***ing confirmed" and a side comment from Kari about how whatever d*****bag use to own it must have never been laid. There are some positives like a beautiful Lumar 32% tint job, keyless entry with remote trunk release, an Alpine CD Player, and Pioneer speakers in the door. So at worst, you can sit in your driveway and listen to music with a bottle of Jergens and a picture of Eliza Dushku. I really wouldn't recommend taking it on the road until you replace the tie-rod ends. You might crash into a bus full of nuns and then the Pope will reign motherf***ing hail fire down on your betrodden a** with more fury than the inquisition because you actually decided to drive and be seen in such an amazing POS, killing 20 of his lovely Sisters. One other thing you might use this car would be pushing it off a cliff. If you've ever wanted to see what it's like first hand for a car to fall hundreds of feet and smash against rock, then here's your chance. Although don't be surprised if this demon-possessed sleigh from hell manages to f*** up your good time even in that bold scenario. I don't know how it would, but it would probably figure out a way. If there are any parents out there reading this, don't let your children fall into the situation I'm in. I would never have ended up with this car if I had pursued a real career. But instead I majored in math where the best job I can find now is up in Portland with a bunch of bran muffin eating hippies, jerking off Moose for 75 cents a smile for some wildlife conservation sperm bank. Let your kids do something with good with their future, like wait tables at Denny's. Oh yeah... it's white, 4 doors, and automatic. Whooptie-f***in-do!  

Topic by ry25920 8 years ago  |  last reply 8 years ago


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....

Topic by Downunder35m 2 years ago  |  last reply 2 years ago