DIY Powder Coating

If you don’t yet have a toaster oven you can’t use with food, here’s yet another reason: DIY powder coating. Powder coating is much harder and more durable than paint – a property imbued to it by the fact that it’s baked on to a part. [Thomas] had a go at powder coating some skateboard trucks, and with the right tools, found the process downright easy.

[Thomas] only needed a few things to powder coat his parts, the first and most important being a powder coat gun. A few years ago, Craftsman produced a powder coat gun that’s still available on Amazon and eBay for about $50. Powders are plentiful and cheap in small quantities. The only other tools needed were an N95 or better respirator, some high temperature tape for masking off the part and a toaster oven. If you want to coat big parts, there are DIY oven options for that.

After the part was sandblasted down to bare metal, [Thomas] masked off all the holes and threads of the part with polyimide tape. Any tape that’s capable of withstanding high temperatures will do, and most of us have a roll of Kapton sitting next to a 3D printer, anyway.

The part is coated with powder via an electrostatic charge, and this means attaching a ground lead from the gun to the part. After that, it’s just filling the gun with powder, putting it in the oven set at 450°F, and letting the powder liquefy.

In the video below, you can see [Thomas] sandblasting, powdering, and baking a set of aluminum skateboard trucks using his method. Compared to other methods of finishing metal parts – anodizing or plating, for instance, powder coating is remarkably easy and something anyone can do in a garage.

Thanks [Tyler] for sending this one in.

61 thoughts on “DIY Powder Coating

    1. It’s not hard to find free or cheap kitchen ovens that are discarded after a remodel. If you have room for a shop oven and a 240V outlet (unplug the clothes dryer for a bit?), it’s an easy way to get a powder coat oven that’s bigger than a toaster oven.

      1. or just get a toaster oven, pennies from a yard sale, or ~$20 from Walmart. more then enough for many non-food purposes (I’m gearing up for making powder coated lead bullets and one-off cast aluminum parts, {I’ll be using oven bake clay for the positives})

  1. “Any tape that’s capable of withstanding high temperatures will do, and most of us have a roll of Kapton sitting next to a 3D printer, anyway.”
    nope. i’m just a worthless cripple. money is one of those things i only have for one day of the month to pay for my medications.

      1. Ok. Time and money I get. Although.. not sure how you could have a hobby without time to spend on it. I’d even get it if you just aren’t interested. It’s a vast hobby with room for a lot of different kinds of interests. Nobody can do it all.

        But, space? How big do you think 3d printers are? I don’t think the author was talking about one of those super expensive refrigerator sized ones. Even someone who lives in one of those converted shipping crate homes ought to be able to fit in a small desktop printer if they wanted one.

        The space comment makes me think you are inventing excuses.

      1. I have used their powder and it is fine. It sounds like you might have had a pressure or moisture problem. It could also be that the powder got too hot at some time in the past before you used it. That can cause it to clump.

        Their gun is usable too.

        1. The problem was not moisture or pressure. I was using the same setup that I use with the powders I get from Caswells and I get great results from them. It’s very possible that the powder got too hot in transport since I live in the desert.

      2. It seems to really depend on the batch. I’ve some really good powder as well as some really horrible stuff (it was one big clump when I opened the container) that I ended up returning. Quite a few people I know have used it and found tricks to deal with minor issues like small clumps such as using a mortar and pestle, a tea strainer, etc. When dealing with small quantities sold in large lots, problems will abound.

      3. I’m happy enough with the HF gun (not having used any name brand ones), but I wasn’t impressed by the quality of the HF powder’s finish, either. It doesn’t seem to melt uniformly like the better powders do. Caswell’s and Eastwood are two online vendors I’ve used. Eastwood has a nice low-temperature clear coat that really makes the base coat pop.

        Some of the early problems I had with the finish were due to trapped oils or solvents outgassing from the part during curing in the oven. I pre-bake parts now, let them cool, then coat and bake.

    1. I would never use their powder. Get it from a real source. I got their gun though, and from what I hear it’s great but I haven’t been able to use mine because I still don’t have an air compressor… I’ve been using my first powder coating gun, one of those Craftsman self-contained units as seen in the article, which I got for $24 new on clearance. :D

      I’ve gotten powder from Eastwood and from Columbia Coatings… I highly recommend Columbia Coatings, they have some amazing colors, specialty materials, textured finishes, and even matched industrial equipment colors. (For brands like Caterpillar, Cub, International, John Deere, Kawasaki, Kubota, etc.)

  2. You can anodize in a garage just fine. The biggest problem is getting all of the parts together and the knowledge of how to do it. Scaling it up is a different story and there are a lot more “moving parts” compared to powder coating. Anodizing also doesn’t hide any flaws, unlike powder coating, which adds geometry to the part.

    The other difficulty is that anodizing cast aluminum often times does not work very well due to the chemistry. These do not appear to be precision milled skateboard trucks made from known wrought alloys. Powder coating does not have this issue.

    Depends on what you are trying to accomplish. Both have their place but both can be done in a garage.

  3. I’ve been unable to control the temperatures inside toaster ovens. The ambient air temperature isn’t a good indicator of the temperature of the parts because much of the heating is radiant and not convection. The radiant heating causes different shaped parts to heat at different rates. Has anyone found a solution to this?

  4. The powder coat gun.. could buy. A toaster over… could buy, but the need to have a sandblasting cabinet and equipment etc. just makes it a dealbreaker.

    If the surface isn’t prepared properly, the paint will flake off or not stick in all the places to begin with.

    1. on guy recently (the 18 videos on prototyping) said you could use a bathroom clearing product that contain grit (forgot the american brand, it’s Cif in France) instead of sandblasting.

      1. Comet is the US brand. Really anything that gets your part to pass the ‘wetting test’ where water sheets rather than beads up will work. [AppliedScience] also recently put out a video on paint prep.

    2. I don’t always sandblast for prep. Sandblasting can warp sheetmetal pretty badly. I have had good luck with fine emory paper or the scotchbrite abrasive wheels. Clean stuff up with lacquer thinner to get all the oil off after whatever prep you use.

      1. Lacquer thinner doesn’t always work either. Lacquer thinner does just what it says, it thins oils. To get a good bond for paint or powder coat you need the oil completely gone. You need to mechanically remove the oil or chemically break it down, this is where sandblasting or abrasive bathroom cleaners (ie; comet) come in.

    3. Is media blasting absolutely necessary? If you weren’t removing a previous powdercoated finish could you just lightly sand or scour the part, combined with a suitable cleaning solvent to remove any grease or oils?

    1. Trophy goes to scgibson81 for the coolest comment! Kudos to all those who make their own stuff.
      (FYI: the H in HTTP is missing from the first link on the page you linked to).

    2. very interesting. Call me stupid, but I can’t find the info: are you using a AC high voltage or DC? it seems that people use DC on the internet (which would make sense for particle transport)

  5. I have one of those Craftsman guns. :D It’s been a while since I used it… Now that I have a 3D printer, maybe I should do what I said I’d do “If I ever got a 3D printer”; make an adapter for it to take interchangeable screw-on bottles instead of that half-assed cup that traps so much wasted powder in it that it has to be washed out between uses.

    Check out Columbia Coatings. They have some amazing powders.

    I have a big Black & Decker infrawave oven that I modded for reflow soldering, and then had to unmodify because TechFX went poof and took the software for their controller board with them… I added a 0.5×0.5″ aluminium angle as a shelf rail to either side of the oven, up near the top, so I could top-mount the rack, and hang the parts. So, I hang the parts from the rack, hang it in a box that acts as ‘spray booth’, ground the rack, powder coat the parts, then transfer the rack to the oven.

    btw, if you’re doing large pieces of aluminium, it’s been my experience that you should take them up to temp for a minute, take them out of the oven, and -then- powder coat them. Otherwise they like to off-gas through the powder as it’s curing and blister it. (There’s chemicals you can dip them in to take care of this, but I couldn’t afford them, and I found if I just let the parts off-gas, coated them, and then baked them, it turned out fine.)

    I also recommend sandblasting; it evens out the finish, preps the surface, and eradicates all sorts of blemishes. (Especially if you’re working with like 1/16″ sheet for a control panel or something and it’s got scratches in it from working on it.) I don’t have a blasting cabinet or anything, but my sister’s BF’s family does, and his father was nice enough to blast some parts for me.

  6. From the looks of it you could instead of a powder gun also simply get one of those flour/icing shaker for the kitchen instead, since the gun in the video is just pouring the stuff on, and those shakers are metal too so they cold transfer a charge I imagine.

    One of these http://www.aliexpress.com/item/Stainless-Steel-Flour-Sifter-Manual-Mesh-Flour-Sifters-Flour-Shaker-Strainer-Sugar-Icing-Shaker-Kitchen-Baking/2010233982.html
    Or these http://www.aliexpress.com/item/Stainless-steel-Semi-Auto-Sieve-Cleaning-Kitchen-Mesh-Flour-Sifters-Shakers-Sugar-Shaker-Sieve-Tool-Cup/32276932616.html

    So what do you think? would it work?

    Of course then you’d need to find a way to supply the proper voltage to the thing and all, but I’m curious if it could work.

  7. there is no mention of what kind of “powder”, it can be many different materials, I had a pump action shotgun “powder coated” with teflon.

    the stuff we mostly see, milk bottle holders (they still have them?), greeting card racks and other bent wire products are polyethylene which is really easy to do.

    I learnt how to do it in tech studies back in the 70’s and have been coating pretty much the same way ever since, with a few mods based on what was at hand.

    You can use your kitchen oven to initially heat the piece, just don’t use it to “flow” after you have applied the powder, in high school we used an oxygen/acetylene flame, with a wide, damn near shower rose sized head, since then I’ve used straight propane with a (I think) paint stripping head.

    Basically hang the piece with a thin bit of wire in a way you can get a flame to the whole piece without touching it.

    If you’re heating up with a flame, work fast and evenly, it takes a bit to get the hang of how long and how hot.
    To check if you are ready to apply powder, try a pinch on the piece, it shouldn’t smoke too much, but “stick” evenly and when you “knock” the piece excess will fall off.

    For an improvised, fluidising bed/chamber I’ve used an old metal rubbish bin and lid.
    Cut a hole near the bottom for a vacuum cleaner hose/weed blower/other air movement device, attach your hose, put a few inches of powder in your chamber.

    When you think your piece is hot enough, transfer it to your chamber, have it hanging above the powder, turn on the blower of choice.

    That last step needs to be done quickly, but don’t rush it.

    After you’ve been listening to powder swirl around for a bit, kill the blower, wait, lift the lid, give your piece a “knock” to remove the excess powder.

    Then hang your work and play your gas flame over it, you’ll clearly see the powder “skin”.

    Again, work quickly and evenly, don’t rush and don’t keep the flame still.

    After it’s cooled enough to NOT leave finger prints (this is the bit I always stuff up with any surface coating), remove your hanger wire, if you need to cut a bit of plastic away that is fine.

    Then carefully heat up the hanger area with your flame, sprinkle a bit of powder over the area, knock off the excess, play the flame over the are until it skins.

    It will help if you hang your piece from a place where you can’t see it in the finished item.

    Now before the usual suspects pipe up with their two cents, this is not an ideal fluidising bed, but if you want to make a “proper one” you will need way more powder, on the order of ten times!

  8. “After that, it’s just filling the gun with powder, putting it in the oven set at 450°F, and letting the powder liquefy.”

    I’d much rather place the coated part in the oven.

  9. Surface prep must be everything. I have seen too many powder coated things that rust underneath and peal off in thick chunks. Does anyone prime anything first, and with what?

    1. Metals may *look* clean to the eye but could be completely contaminated with oxides, chemicals, or oils from your hands. You don’t have to sand blast it to remove this. Sand blasting certainly helps to remove a coating that was previously applied… but not necessary for fairly clean metal surfaces. As many have mentioned, cleaning the surface with an abrasive pad (scotchbrite) and some isopropyl alcohol will help to remove most surface contaminates.

    2. I never did any powdercoating, but auto paint is quite sensitive to oils and rust on the surface. No primer has ever prevented leftover rust from poking through.

      There are nice products available at your auto paint supplier: for rust there is a solution of phosphoric acid which changes rust to “black rust” (whatever that really is) and stops it from coming back through your finish. To get oils, grease and silicone off, there are “prep solvents” that work really well. Both products are quite cheap and easy to use.

      1. the “rust converter” converts iron oxide to iron phosphate, which is harder than the steel underneath.

        You need to watch out as some of these products have a resin base included

          1. the one I use is “Ferropro” rust converter, it’s quite thin, brushes on really well.

            When it dries it is quite glossy and takes paint, enamel(ftw!!!) or acrylic really well

      1. That’s definitely not 150 PSI of pressure on it in the video :)
        Mind you, a compressor is always handy to have so it’s more a universal purchase rather than a powder-gun thing only. So I’d write only a small percentage off on the cost for powder coating.

  10. On pressure, I bet that the Craftsman gun’s blower generates only a fraction of a psi. Furthermore, I’m certain that a breath powered powder coater would work just fine. You would need a check valve to insure never inhaling the powder, a small orifice to even out the flow rate, and a dryer cartridge to remove the moisture in your breath.

    As with paintwork, it’s all about surface prep. For ferrous metals, I’d advise a phosphate acid rinse (like Jasco) which is what body shops use as the last step before paint. It’s cheap and available anywhere auto paint supplies are sold.

  11. And now for something completely different! I was turning out “powder coated” parts decades before powder coating was invented! Just brush on Sears 2 part epoxy boat paint (available in black!) When dry of solvent (about an hour), it looks like absolute crap, and takes a full week to set hard. Pop parts into your kitchen oven as it does not smell or drip, and bake at 375 degrees for 20-30 minutes. Parts come out fully hard set and with a perfect reflow gloss as fine as any powder finished part I have ever seen! The set epoxy is more durable than any powder coat I’ve seen. And the only equipment needed is a cheap disposable brush and your kitchen oven. It is truly quick and easy!

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