Thursday, July 17, 2014

Powder coating: It's an electrically charged awesome.

One of my biggest hurdles in gun building, believe it or not, has been coating the finished product. While there are a variety of different products on the market, each one has it's own issues for a garage builder like me. Bluing, parkerizing, duracoat, cerakote, spray paint, and a number of others, each with their own inherent benefits and detractions. Most of my guns have been coated with the Krylon touch, but that leaves a lot to be desired. My shop is almost too dirty to do spray coatings like Duracoat in, plus the fumes would get to be an annoyance.

Recently, I was in Harbor Freight, and saw that they had their powder coating set up on sale, and I had a 20% off coupon, so I walked out a happy man. I figured I could afford to lose that much money if it didn't work out, or I couldn't get the hang of it. I already have a sandblasting cabinet, so that part of the equation was covered. All I needed was an oven that could reach 450 degrees.
A quick stop by my local Chinese wholesale mart (also known as Wal Mart) netted me a toaster oven for about 50 bucks that is large enough to cook most of my powder coated parts in.

Powder coating is a pretty cool process, in that it sprays a positively charged cloud of colored powder at an object that has been grounded. The powder is attracted to the part like a magnet, and the powder is held in place via static electricity (more or less). The part is put in an oven and the powder is melted and fused to the part. It requires a very clean surface, and media blasting the part beforehand to get some "tooth" for the coating to adhere to.

I've been working on a 9mm conversion for the AR15 that is inexpensive and doesn't require any modification to the rifle. Most of the conversion kits out there are very expensive (200 bucks for a bolt, 100-200 for a barrel, 50-200 for a mag adapter, etc) and since I can build a complete AR rifle for less than 400 bucks these days, that just didn't set well with me.
So, I needed a conversion kit, and true to my typical nature, I don't want to spend much money. A starting point would be magazines. The Colt mags are great, but expensive, and are really just Uzi mags with a mag catch milled in, and require an adaptor. After digging around, I found a reasonable solution: Sten mags. They're cheap, hold plenty of ammo, and can even be used with other calibers. The best part? They fit in the magwell quite nicely, and only require a filler piece on the rear of the mag.
I took 3 mags out of the stack of Sten mags that feed my Sten, and dedicated them to this purpose. Since they were rusty, greasy, and altogether cruddy looking, I figured they would be good fodder for this project.

The mag block, fresh out of the mill.

A Sten mag in place with the block. The block is held in place by the AR mag release.

Mocked up right purty.

They are a good fit for the AR pattern rifle. A bit of a bitch to load, but there are plenty of mag loaders on the market that will work with the Sten mag.
Since the rifle was going to get refinished, why not the mags?

Now, these mags were all military surplus that had been dunked in cosmoline and stored for years in a vault in somewhereistan. The oil from the cosmoline had soaked in pretty good, and made life a living hell. I couldn't get all the oils out, no matter how hard I scrubbed. I finally media blasted the mags, then put them in the oven at 450 degrees for 20 minutes.
Turns out, the oil seeped out of all the hidey-holes, and I was finally able to remove it all. I put the mags on a fan to cool, before dunking them in solvent.

After the mags had cooled, were degreased again, and blasted again, I put them in my hi-tech powder coating booth (the box the powder coating rig came in, with a metal hanger stuck through it) and sprayed some Harbor Freight matte black powder on them. That stuff is about 6 bucks for a pound, and it takes about a spoonful to do a mag or three.

Believe it or not, this is the coated mag.

While they're getting powder coated, I turn the oven on to 450 and let it warm up. I then hang the three mags from a rack that came with the oven, and set the timer to 20 minutes.

Within a minute, the powder melts, and gets a very glossy and orange-peel-ish look. After 10 minutes, it's very evenly coated, with a nice gloss. As it cools, it dulls slightly.

Giving the floor plates the same treatment.

The finished, unassembled product. Ignore the water droplets on the floor plates.

Assembled, with a light coat of gun oil spread on with a towel.

Finished, and installed in the blurry gun.

The finish is very tough. It does not scratch easily, and solvents won't touch it. The best part? Over 6000 different colors available, and it's cheap.
I don't know how it would hold up on a barrel or a similar object that gets hot, but so far the mags and receivers I have coated have held up well, and still look good despite a few trips to the range and a lot of shooting.

This weekend, we will find out how well my 9mm conversion works; more on that later.


  1. Wel, you have my undivided attention now. I will be starting an AR build soon, and the option to have a 9mm PCC upper that works with the standard lower is really appealing to me.

    1. The selling points:
      A 9mm upper that requires no modification to a standard lower, can use a run-of-the-mill upper, uses a standard hammer and FCG, uses cheap mags, and is altogether inexpensive to make.

      I'm still looking at the price I would market these for, but I figure in the neighborhood of 200 dollars for the barrel, bolt, mag block, and a mag.

  2. You put the gun oil on just to sexy them up dinja. Hardly needed with the powder coat.
    I feel an urge to find something that needs a good powder coating now.
    As usual, cool stuff TRE. enjoyed the post.
    PS. $200? Really? all that for $200?

    1. Actually.........................yeah. I wanted it just a shade glossier, and a light coating of gun oil did exactly that.

      Anything electrically conductive can be powder coated. There's more on this particular gun that will be coated, as well as a number of other things. Once you see how easy it is to do, you find yourself wandering about the house, looking for things to glossy up.

      PS: Yup. That's if you put it on a upper you already have. Stripped uppers are in the 50 dollar range currently, so add 50 bucks to that 200. Still, 250 bucks to shoot cheap 9 sillimeter out of your AR? You'd save that in just one blogshoot.

  3. I went through this puzzle when I first got my lathe and mill back in '03/'04. There's a lot of info on home anodizing, and it doesn't look terribly involved. Almost went that ways, but powder coating is still much easier and like you, I went down the powder coating path. I got my cheap setup at Sears. I think anodizing gives more precise control of the thickness than painting, by controlling the current and time. They get all kinds of funky colors with RIT dyes - the kind they use for dying clothes.

    I have an old toaster over that we never used and everything has fit in that pretty nicely, but I tend to do smaller things. So far.

    1. I'll agree that powder coating has proven to be very effective in cost, ease of application, and durability. I am a fan of anodizing as well, but it is single-purpose; it serves only aluminum parts and really nothing else. The powder coating works on anything conductive.
      Well, anything conductive that can survive 450 degrees in an oven. =)

      I've found that, in the case that something is to be a single color, I can preheat the part, then spray the powder, and get much better coverage than simply spraying "cold". The remaining heat seems to just barely melt the powder as it tries to cling to the surface of the part, and certainly makes it easier to see that you have effectively coated the part.

  4. You are making me more and more jealous every post :p

    1. That's certainly not my goal, but I'm glad you found the topic interesting.