Grinding PET Plastics

Hello, I have recently been working on shredding PET plastics (#1 recycling symbol), to recycle the plastics into 3D printer filament. I have been struggling with finding a reliable and inexpensive method for grinding or shredding the plastics. The granules also need to be fairly small. Please share any thoughts you have! Thanks!

Posted by DylanD581 2 years ago  |  last reply 2 years ago

What is the best way to grind glass, somewhat smooth? Answered

Now before you rush to write down an answer let me tell you the details! The chunk of glass is 28 inches wide by 28 inches long and 2.5 inches tall. Composed of 160 painstakingly cut strips of glass that have been glued together into a jumbo block. Now try as I might, when laminating things together of ever so slightly different size together you are going to get high and low spots - And yes, this would have been soooo much easier a job if I had smoothed out the rough edges before laminating - Pesky hind-sight. Unfortunately my planer doesn't seem to work so well on glass, who knew :) Anyway, I will post some pictures to give you an idea of what it is, that has to be ground down. First off • It does not have to be perfectly smooth • A mottled surface would actually be appreciated • It is not going to be a lens of any kind, all though light will be transmitted through it. I have the following tools, but first - No I am not taking it 1700km to have it kilned. No, the local glass shop seems to have less tools then I do, at least in this scale. • Angle grinders • belt sanders • orbital sanders - but really? On the back side I used the angle grinder, with a metal grinding bit. Not to bad really all though the edges were taking a pounding. This was prior to applying resin and woven cloth, to give the glass a bit of tooth and reduce the high edges. This is for an instructable I am working on.  

Asked by iminthebathroom 7 years ago  |  last reply 5 years ago

QUICK: Sea Stone Pigments? How to break up stone into powder?

Over the summer i have thought up of turning stones you find by the sea side into pigment. I have searched forever since then and I cannot find the cheapest way to break up these stones into pigment. Any ideas of things I could try would be great. Thanks.

Posted by Kaffe 7 years ago  |  last reply 7 years ago

Grinding Flour from Wheat? Answered

This season, I plan to plant 4 sq. meters of my garden with hard wheat, with the intention of making bread.  I have no idea how I should make the transition from berries to flour, though.  I have read online that for small quantities one can use a blender.  I have also read that that produces highly inferior flour.  I would prefer to spend no money, but I could allow $20 or so.  Does anyone have any suggestions or ideas?  I am not opposed to high-labor options.

Asked by tincanz 6 years ago  |  last reply 6 years ago

What grinds my gears

You know what really grinds my gears? This forum is made by me you should just tell me what makes you angry or grinds your gears.An example would be" you know what really grinds my gears when people fart in public then don't say anything and they do it repeatedly."

Posted by shawntherobot 9 years ago

An alternative to expensive grinding stones

For some people buying a decent grinding or honing stone is a lifetime investment.Prices of over $500 for a single stone of a very fine grid are not uncommon.But what about the average Joe who just needs to sharpen a knife or tool every now and then?If slicing and dicing is not your living than investing in a set of diamond plates might be better than getting a set of stones.But there are limitations, firstly their size and then how long they last.The later is really important if not used correctly as even diamond toold can be ruined quickly.In some case these small sharpening tools are hard to handle.The bigger plates can still be a pain if they don't come with a proper mount.Well, and if you forget to clean them after use and put them in a dry place it will be quite hard to remove the rust.A nice alternative I found is sandpaper, specifically sandpaper on a glass plate.Good wet and dry sandpaper is available from almost gravel to a 10.000 grid, above that you might have to make a special order.In general the finer the grid the more you pay due to the ingredients.I use a glass plate from and old scanner as they are both heat proof and really strong, window glass is not recommended here.The glass is covered with strips of kapton tape for the ease of later cleaning.The tape is then evenly covered with a contact glue, preferably the spry king to get an even cover.Same for the sheet of sandpaper.I try to get the glue over the glass edge a bit and to have at least two sides of the sandpaper going over an edge.Just to have an area to work close to the edge without risking to lift the paper off.Once a sheet is too worn I place the plat in the oven for a few minutes so the glue softens and peel the sheet off.If too much glue remians on the tape I replace it before I put a new sheet on.Of course you need a bunch of plates although it works fine with two different sheets halfing a plate.The thing works best under slow running water, so use your tinker skills to come with a suitable frame and water supply ;)But even with just a spray bottle it is a cheap way to replace a costly stone, especially if you do require a bigger surface area.

Posted by Downunder35m 3 months ago  |  last reply 3 months ago

Please suggest components for a water spray/vacuum system for cooling and dust collection while grinding. Answered

The grinding is being done in a tight area. A long handled grinding disc (please see picture) is being used. Only the grinding disk rotates, not the long handle.  It would be best if the water lines and vacuum lines could be attached along the handle, welded? cable ties?  The system needs to be portable but electricity will be available. The smaller the components, such as water reservoir, peristaltic pump, vacuum pump, vacuum holding tank, spray nozzle, tubing, the better. The material to be ground is heat sensitive so the water spray is needed for cooling.The water pump needs to be a peristaltic type pump so that the fluid is only in contact with the tubing.  I will also need a way to connect the flexible tubing of the pump to a more rigid, perhaps metal fluid line along the handle..  Due to the small grinding surface, water flow does not need to be great, perhaps 20 ml per minute.  The dust produced from grinding can obscure the view so a vacuum source is necessary.  I welcome any suggestions on:  how the system could be designed, what components I would need,  where components could be purchased,  how to keep costs down, etc.  I greatly appreciate any guidance you can give me.

Asked by jadeway 9 years ago  |  last reply 9 years ago

How to grind or shred aluminum cans?

Greetings, I'm am looking for methods to grind or shred up aluminum cans enough to be put in a ball mill (rock tumbler with steel balls in it) to make aluminum powder. I read that a stone grinder will cause it to melt. I read that aluminum foil can be ground in a blender then put in a ball mill, but I think aluminum cans might be too thick? Thanks

Posted by NeuroPulse 10 years ago  |  last reply 8 years ago

Inexpensive way to grind plastic bottles?

Greetings, I am looking for an inexpensive way to grind individual plastic bottles into particles for easy melting in molds. I tried a blender. It just scrapes it very loudly and burns it. It doesn't break it up. Thanks

Posted by NeuroPulse 9 years ago  |  last reply 1 year ago

attaching grind plates on aggressive skates

I havent ridden my aggressive skates for a while so i cant remember which side to attach my grind plates, (for some reason i took them off when i stopped usin them.) can someone help.

Posted by XI3 10 years ago  |  last reply 10 years ago

What Grinds My Gears on Instructables

What Grids My Gears on Instructables: -When peaple hold there parts/esplainin things up to a web cam and you can see them. -WHEN PEOPLE TYPE IN ALL CAPS! -When some one asks how to do somthing when it is explaied in the instructable like 10 times. -When people talk crap about good instructables -Pointless K'nex instuctables for things that eithere aready exsist/are easier to make with OTHER materials -Rock band/Guitar Hero -When some one posts something 2 months after it has already been posted and says "they didn't see it." -Peice o crap duct tape objects Plese post what grinds your gears in the comments.

Posted by Clayton H. 10 years ago  |  last reply 8 years ago

Is this 4-Sided Diamond Hone Block any good? Answered

4-Sided Diamond Hone Block  I was wondering if it would be a  good idea to use this to polish up my katana that I'm building. I already have a whet stone but it powders easily and seems  to not be able to handle the job. also it takes forever i want something with a lower grit.

Asked by the_burrito_master 8 years ago  |  last reply 8 years ago

How can I cut geode, is it possible to cut with a dremel? Answered

Basically, I want to try and make jewelry with a geode stone I bought. But when I tried to cut it with a tungsten carbine cutter, the stone turn red and it smell like some burnt stuff. It also happen when I tried to grind with aluminum oxide bit. My geode crystai Is quite thick. Please tell me how can I cut/grind the geode?

Asked by Shizen 4 years ago  |  last reply 1 year ago

Is using a wet grinding wheel or a wet belt sander easier to grind curved glass pieces?

I make lamp shades out of glass pieces. I take glasses in different colors break them apart and then wire them onto frames to make the shades. I have found that hand sanding down the edges on these pieces just takes too long to do. I am contemplating getting a sander but am wondering wether the flat surface of the belt sander will work for the curved pieces of glass, or if a wheel would get into the curve better. Anyone had any experience with either method?

Asked by abborn 5 years ago  |  last reply 5 years ago

should I post ramp and grind rail?

Should I make an instructable for a nice DIY bike ,skateboard, roller blades, ect. ramp and a simple sturdy skate board or roller blade grind rail? 1-3 are of the ramp obviously that i made quite recently.4 is of the grind rail its like a year and a half old so its really beat up it was a lot better new ,and i figured out a better way to build is the ible so far tell me what ya think

Posted by the_burrito_master 10 years ago  |  last reply 10 years ago

What is the best type of ball milling media?

I'm trying to decide what kind of grinding media to use for crushing powders in my ball mill. Is it better to have different sizes? Also, is it true cylinders work better that spheres? My two main choices are either brass balls or alumina cylinders, which one should I pick?

Asked by Ke-Bob 8 years ago  |  last reply 8 years ago

Will hardened lead antimony balls wear out quickly in a ball mill?

I've read that regular soft lead balls can wear out extremely quickly and contaminate mixtures in a ball mill, but what about these hardened lead antimony balls? I don't really fancy the idea of breathing in a lot of lead dust after a couple hours of milling. Would it be a good idea to get the lead balls from this website (found under "ball mills and media") for my ball mill (for making potentially explosive chemicals)? I've considered getting brass balls, but they are unbelievably expensive. I've also considered getting a brass bar and cutting it, but that's not cheap either and I don't know where to get a brass bar. Plus, apparently brass wears down quickly too, so it seems like a lot of trouble when I can just get lead balls, as long as they don't wear out too badly.

Asked by Ke-Bob 8 years ago  |  last reply 8 years ago

why is my 2009 grinding into 1st and 5th gear?

We just had the clutch replaced in our 2009 Toyota Corolla.  Now it grinds going into 1st and 5th gear.  We have never had any problems with it prior to that.  Is it possible that the clutch isn't adjusted right or is the synchro bad?  It drives worse now than before replacing the clutch.

Asked by PatrickB134 2 years ago  |  last reply 2 years ago

Diamond grinding wheels: which alloy holds the diamonds???

Diamond wheels are increasingly cheap. So cheap, I'm contemplating using them as steel disks in a wind generator. But it hurts to leave this magnificent technology unused.  The binding metal looks like silver brazing alloy to me. What is it, how can I take it off, could I re-use it... Perhaps not now, but I could picture a huge cup shaped wheel to grind a glass blank to a pre shaped telescope mirror

Asked by BobS 9 years ago  |  last reply 9 years ago

How do i make a bicycle helmet larger?

It doesn't fit my head. Should i sand it with my dremel? I don't have anymore cutting wheels.

Asked by Yerboogieman 9 years ago  |  last reply 9 years ago

Stepper motor vibration/lockup with driver? Answered

I am trying to get a stepper motor to turn using a StepStick driver from Botronicz. I have gotten the driver to work once before, but now it has decided not to work. I have wired my stepper motor (Model STP-42D3018) according to any specs I can find online in a bipolar connection, but when I fire it up the stepper only sits there and vibrates. Or misses steps (depending on voltage). A few other times I had it also where it would step one direction for I think a single step and then step back the other direction. It is really bothering me because I have tried multiple other wiring combinations and have not gotten any of those to work. My current setup is exactly like this (I have checked numerous times). I have also tried changing the vmot supply voltage and current limit, as well as the current limiter pot on the board itself. If anyone can help it would be greatly appreciated! Sincerely,  A907

Asked by astroboy907 5 years ago  |  last reply 5 years ago

How do I grind up demagnetized neodymium magnets? Answered

I need to know so I can do a project oh and I cant think of a way aside from using a blender

Asked by nerd7473 5 years ago  |  last reply 4 years ago

Suggest me the difference between CNC milling and CNC grinding ?

I have been researching CNC milling online at and other sites. I want CNC milling for the removal of metal by feeding a work piece through the periphery of a rotating circular cutter. But, I did not know the difference between CNC milling and CNC grinding and which one is suitable for shaping a material, Does anyone have any suggestions for CNC machine that would meet these needs? Thanks.

Asked by 9 years ago  |  last reply 9 years ago

Is there an easy and safe way to trim/grind the edge of a glass plate? Answered

I'm trying to fit a pre-cut mirror glass (rescued from a $5 Wal-Mart mirror) into the back of a shadow box.  The mirror itself is not quite square, so there is one corner and part of the adjacent edge which won't quite fit into box (about 0.5 mm overlap).  If this was wood or plastic, I'd grab some sandpaper and bring the edge down to fit.  Is there an equivalently easy, but safe, method for doing the same with glass (3 mm thick)?

Asked by kelseymh 5 years ago  |  last reply 5 years ago

My chisel has a chink in the blade, how do I get it out? Answered

I was wood carving one day to find that my flex cut chisel had a large, crescent shaped chink right out of the blade, it is about 1 centimeter deep and is a real nuisance, I was thinking about going to my local woodcraft store to ask a pro how to do it, but I thought that before I drove out there, I should ask on here, so anyone that knows what they're doing, can they give me an Instructable or tell me how to get it out? I want to start carving again ASAP! Thanks Future Filmaker

Asked by Future filmaker 9 years ago  |  last reply 9 years ago

Here're some primers for basic techniques in the machine workshop.

I've posted this link elsewhere on 'ibbles, I make no apology for that, just spreadin' the knowledge :-)Covers the basics of workshop practice courtesy of MIT robotics lab. It's quite dry, but I bet these guys really let go at the weekend.Robot delivery roomEnjoy!

Posted by bosherston 9 years ago

Will glass marbles cause static electricity when used in a ball mill to grind black powder?

Will glass marbles cause static electricity when used in a ball mill to grind black powder? it's for a homemade ball mill.

Asked by tomaatesoep 9 years ago  |  last reply 4 years ago

Improvised Mortar and Pestle

I need to grind some kno3 but i dont have a mortar and pestle or a coffee grinder. is there any way to improvise using household items? by the way, the kno3 is pretty strong stuff, so it will take some force to grind it. any ideas?

Posted by DELETED_DELETED_kruser495 10 years ago  |  last reply 10 years ago


Here it comes again! Weeee! Get those idea-wheels grinding!

Posted by Kiteman 8 years ago  |  last reply 8 years ago

Name brand vs generic dremel? Answered

I'm doing a project that involves grinding PCB slots off of an aluminum enclosure and making everything fit right - due to the shape of the enclosure it looks like I will need a flexible shaft in order to get into the case. A Dremel seems to be a good tool to use, however I am looking for something that will be able to grind aluminum fairly fast. Dremels, at least with flex shafts, are expensive. I'm looking for around $40, and this seems to fit. Has anyone had any luck grinding aluminum with a non-name-brand dremel? What about Dremel branded accessories vs ebay accessories? Edit: currently the one I'm looking at is this

Asked by astroboy907 4 years ago  |  last reply 4 years ago

How can I make a simple soap noodle melting, mixing and grinding machine

Hi from Honduras! Our currency is way down and it's very hard for us to import even simple small machines. I am a women with physical disability and have started my own homemade soapmaking shop. It is very hard for me to be hand mixing, grinding and melting ingredients such as herbs and soap noodles and/soap bases. These simple acts does put a toll on my hands and arms. Can anyone aid me? I appreciate your comments. Gilda

Posted by amparosinlimites 11 years ago

How to clean dremel bits?? Answered

Can anyone help me clean my dremel bits? I recently bought a grinding set for my dremel to use on my Traxxas car. After using it on the plastic chassis most of my grinding and sanding bits are covered in plastic. The reason is because the plastic heats up when I use it and the plastic melts onto the grinding stone. I thought of maybe using a lighter to maybe melt the plastic off but it just burnt the plastic and a bit of the stone. It's not that the bits are expensive, I can afford $2 but the gas to go the hardware store is just too much for a couple of bits. I would just use my bike here and there, but it just becomes a hassle go over there every hour. Thanks

Asked by halo99 6 years ago  |  last reply 6 years ago

So one of the ear muffs for my Skullcandy Grind Headsets , came out and know i have no clue how to put them back in.?

Https:// Sorry for the Dis links it was more Convenient.

Asked by Turtlederpy25 1 year ago  |  last reply 1 year ago

What kind of non-sparking ball mill media can I use other than lead?

I want to make a ball mill but I can't find any lead fishing sinkers (they're bad for the environment so nobody sells them anymore). Is there anything else I can use to grind chemicals in a ball mill that won't create sparks?

Asked by Ke-Bob 8 years ago  |  last reply 8 years ago

Dried bean experiment need help or ideas

Greetings,  My experiment, I heard that taco bell makes their re-fried beans out of a bag of dry mix. Im am not sure how true this is but wanted to see if I can make my own mix. My first experiment is to see what happens if one grinds up dried beans and try to cook them. The problem is I don't know of anything that can grind up a dried bean. I did find some grain grinders but I don't know if they are up for the task and the cheaper ones seem to break easily based on the reviews.   I suppose I could bash them between a couple of rocks, but experience has taught me that the part I want to keep will most likely go flying.  Any ideas will be appreciated 

Posted by Bard 5 years ago  |  last reply 3 years ago

how do u get aluminium powder

How do u get aluminium powder? do u just grind aluminium into a fine powder or what??

Posted by 10wellsmit 11 years ago  |  last reply 3 years ago

question about kitchenaid mixers

My family has a 250watt k45ss kitchenaid mixer that my family uses to mix up stuff to bake. My mom with in the past 2 or 3 months has started using it to grind wheat, and she is concerned that she is wearing the thing out. She wants to know if the thing needs oil since it is making a grinding like noise at low speed, and an unfamiliar hum a high speed. so is there anything to be concerned about? (note: the mixer is about 20 years old)

Posted by clasic_traveller_diehard 10 years ago  |  last reply 10 years ago

Sorry for the outage

Our data center had a series of problems that effectively brought Instructables, and a bunch of other servers, to a grinding halt this morning. But, we're back, the problems are isolated, and hopefully won't be repeated. Sorry for the down time!

Posted by ewilhelm 11 years ago  |  last reply 11 years ago

I broke my baby!! (UPDATED)

Disasterous news - I snapped my Instructables Leatherman, that has been somewhere about my person almost every day for more than five years. :'-( It's not an actual blade, it's the awl, but it's still left a painful, jagged stump that stops the tool being pocket-friendly (see the second photo). Do I just grind the stump off smoothly, or can the awl be replaced? UPDATE: it cannot be repaired, only replaced, so I'm going to grind it down to a new, shorter point.

Posted by Kiteman 5 years ago  |  last reply 5 years ago

Abnormal Cyst Within The Jaw Anyone?

Well this is just too interesting not to post. Turns out after going to the dentist for a routine cleaning, that I have a spot in the right side of my jaw he wanted looked at. After going to a dental surgeon he concluded that it is a type of cyst in the bone of the jaw that forms when a wisdom tooth doesn't come in but instead forms a growth of tissue in that cavity. So thinking this was what was going on he went ahead with the normal procedure. To numb me up till I'm almost knocked out, cut the gum line cut the jaw bone to the area and then grind (yes grind with a drill...) the cavity out. After the cyst was removed they would then continue to grind the walls of the cavity to fill in the "hole". From there it would fill in and regrow the bone tissue and heal everything back up with time. But of course that wasn't the case with me. While he was working everything was fine until he came to a hollow area. Hollow. No cyst, no tissue, nothing but a string of a nerve running right through the robin egg sized pocket of air in the middle. He was very confused but after looking at it proceeded to just grind the edges to fill it in and took some for studying. In his 30+ years of doing this he has never heard of or seen anything like it. But he says there's not really anything wrong and that it should be fine. where's that gauze I had...

Posted by Rockerx 9 years ago  |  last reply 9 years ago

Where do you find high-quality dried chiles for stew? What kitchen appliance do you recommend grinding them with? Answered

I want to make homemade chile without a mix packet. Green chile stew would be ideal- our family is mildly obsessed with it. However, I'm not familiar with where to purchase and how to prepare chiles. Where do you buy your dried chiles? I'm looking for high-quality spices (stored in plastic or glass). Also, which appliances do you recommend grinding them with? Thanks, everyone :)

Asked by garnishrecipes 6 years ago  |  last reply 6 years ago

malita cg4 coffee grinder?

Messy and since I don't have the manuals no idea what the contol on the front is for thought it was cups but filled the machine and it grinded till it was empty preety much coffee grounds everywhere help

Asked by mozay827 7 years ago  |  last reply 7 years ago

Where can i find pottasium nitrate(NHO3), and sulfur?

I don't want to use the internet for these, and i made mortar and pestle for grinding with clay p.s. i have the charcoal

Asked by tarheels255 9 years ago  |  last reply 9 years ago

Arc welding : How do I prevent these 'bubbles' from forming? How can I close them without grinding?

I'm self taught, was joining these diesel tanks to make water tanks, so the materials are the same thickness. As has happened many times before with other jobs these 'bubbles' form. It never really bothered me, but it turns out that water will leak out of the flux pool center. After much grinding my teeth and using the angle grinder the job is now complete and watertight. I would really like an experienced welder to give some advice.

Asked by Karroo Oakey 8 years ago  |  last reply 8 years ago

Ball Mill Help? Answered

I'm planing on constructing a ball mill out of pvc plumbing parts. So far I have two questions... ~I need some help with how to get a motor to use to drive it, that wouldn't require 'to much' wiring to set up. I was thinking about using a drill and mounting it some how. ~Second, I would like to know where I could get lead or other non-sparking media other than online. For example, I heard you could use lead fishing weights, if they sell this at a place like Dicks Sporting Goods could you please send me a product number? Thank You for your time

Asked by muffin1 9 years ago  |  last reply 8 years ago

How to use a Jones & Shipman tool and cutter grinder?

Steveastro's magical workshop of many wonderful toys has a very nice Jones-Shipman model 311 tool and cutter grinder, the trouble is however, that we don't have a clue as to how to set it up and use it. Our master machinist says working these things is an art and that its a full 5 year apprenticeship on cutter grinding ALONE. We have a box full of essentially shredded endmills waiting to be sharpened and since we have the tool to do it, it would be quite worthwhile if we could acquire a bit of help getting it up and running.

Asked by The Ideanator 7 years ago  |  last reply 6 years ago

Removing design from class ring?

I feel ridiculous wearing my high school class ring. Has anyone removed the design from theirs and if so, any tips for minimizing the marking from the sanding/grinding?

Asked by idogis1 8 years ago  |  last reply 7 years ago

broken dewalt router

My router started making a terrible grinding noise,so I check the brushes and they are fine.the router cuter fitted in the router does not turn freely and supect its either motor or the bearing can any one help

Posted by ander19 9 years ago  |  last reply 9 years ago

Refinishing Optical Media

I was thinking about ways to actually get good data off of a fucked disk. I figured for a permanent solution, instead of grinding the disk down, or filling it in with greasy things, actually reforming the surface of the disk with some clear resin or acrylic. Comments?

Posted by Crash2108 12 years ago  |  last reply 12 years ago

i have a mig welder and my welds form in balls, i have to grind them down for ages, how can i make them pool?

Please could any EXPERIENCED WELDER advise me?

Asked by l96470fps 9 years ago  |  last reply 9 years ago