Home Forums Reloading Bullet Casting Dry tumble powder coating

Right about a year ago I tried powdercoating my cast bullets by tumbling in the dried powder, and have been using that method since then. (Other people were tumbling in powder/solvent mixtures, which gets messy and time consuming.) I thought I'd share my process and experiences here, after mentioning it in a couple other threads.

The whole process is pretty easy, about the same effort as tumble lubing, but without the wait time for it to dry. My process, from melting pot to loaded ammo, is as follows:
- cast bullets
- dry tumble in powder
- bake 15 min
- cool 5 min
- repeat tumble & bake
- push-through sizer
- load ammo

The best powder I've found is a "grass green" TGIC Polyester from Powder Buy The Pound. I've used a bunch of other powders as well, and each one acts differently. Some form a very tough coating, but the bullets stick together too much, while others don't stick to the bullet when dry tumbling. Don't waste you time with the Harbor Freight powders.
My favorite powder:


I use a plastic yogurt container to "tumble" the bullets, but any recyclable plastic food container should work. I use a few teaspoons of powder for 50-75 bullets. Shake the container by hand (shake hard!) about 20-30 seconds, until the bullets are evenly coated. This is the second coat on these bullets:


Then dump them out in a tray. A bit of metal screen on the bottom keeps the bullets from getting a flat spot in the coating where they touch the tray. Don't touch them, the powder comes right off at this point. If there's excess powder in the tub, carefully pour the bullets out without dumping out the powder too.


Bake for 15 minutes @ 400* (the directions say 10 minutes, but my garage is cold and the toaster oven is small)


I typically apply two coats of powder (2 cycles of tumble/bake) for most bullets, although some claim good results with one coat.

Then size as necessary. I use Lee push through sizers, they size more concentrically than the Lyman style, and are faster. If using gas checks, apply the checks first, do not size before putting the checks on.


more coming...

More bullets.
- The .30 cal rifle bullets are working fine at 2000 fps in my 300 Blackout, and at 2400-2500 fps in my 308. The one at the back right was recovered from a subsonic load; it penetrated about 18" of alder log, and only shed a little of the coating on the nose.
- The expanded bullet in front is from the loaded rounds in the center - 9mm 125gr Mihec mold, with modified shallow hollow point pins, 6.0gr WSF for ~1220 fps. This load needed aluminum gas checks to prevent leading with traditional bullet lube, but now the coating is completely intact around the base and bore contact surfaces with no bore fouling at all.
-The 200gr 10mm Mihec bullets on the left show how the hollow points get nicely coated too.


A bunch of gratuitous powder coated bullet pics, showing how the powder sticks to the bullets through the bore and into the target...

45 Auto huge hollow point


9mm Mihec w/ modified hollow point


300 Blackout subsonic


another 45 Auto


38 Special


35 Remington full power (left) and subsonic (right)
[img]http://i24.photobucket.com/albums/c26/zthang43/Bang/molds/3520cal20rifle.jpg[/img]

I'll search for pics of more rifle bullets; don't have many because the bullets tend to come apart on impact with my backstop.

You've piqued my interest. Powder by the Pound website is not pulling up. Server error. I may have to give this a try with rifle bullets. I've got a 115 rfn 30 cal that I want to shoot nice and spicy, and just got a 22 cal mould that I'd like to shoot sans gas checks if possible. This may be the way. So the screen you've got in the baking pan is just some steel mesh laying in the pan bottom?

I found them on Ebay from their Facebook page. How many bullets are you coating with a pound of powder and 2 coats?

And what alloys are you running for the various bullets? I'm guessing the 45, 38 are very soft, but what about the 10mm, 9mm, and the 308?

So do the bullets have to be warm when dry tumbling to get the powder to stick?

the PBTP website is working for me right now. (Just fyi, the name is Powder Buy the Pound, in case you were trying to access the wrong site.) I don't have an actual count on how many bullets you can coat with a pound of powder, but it's in the thousands. A little powder goes a long way, and none of it gets wasted.

The screen I'm using is actually brass, but it doesn't matter, steel or aluminum would be fine. It's just there to keep the bullets off the bottom.

All of the bullets pictured were cast from air cooled wheel weights. I control expansion by adjusting the size of the hollow points.

458, the bullets don't need to be warmed. I think the powder sticks from static generated from shaking in the plastic tub. The bullets do need to be clean and free of lube, oil, etc, but fingerprints are fine.

Thanks for posting this. I will retrieve my over next trip home and try this method first and then try using the black plastic airsoft bullets as a second try.

I really think the only reason to need airsoft pellets is if you're using the wrong kind of plastic tub (not generating static) or you're not using a good powder.

Also, shake them by hand (hard!), you don't need a case tumbler, as some are using.

No need to complicate the process, what I posted above works really well.

I will give it a try. My trip home just got postponed a month. I may thrift store shop for another toaster oven.

Oh yeah, forgot to mention that part - don't use your wife's toaster oven, and don't do this in the kitchen. Mine is in the garage, and the wife has a new toaster oven (cheap ones are only $20-ish at the box stores)

I had the right site. Their server must have been fritzing. No problem getting to the site today. So there is a difference in the characteristics of the various colors as far as how they work with bullets, and your favored grass green has the proper characteristics? I'm set on trying this now. Going to order a pound of the grass green and give it a go. Thanks for spreading the word!!

I'm glad you mentioned that last point about not doing the baking in the kitchen! I've got a spare toaster oven since I quit eating wheat. Ordered a pound of the grass green. Plan to do a single coat on 22 cal bullets and a double coat on 30 cal and up. Will post my results if I remember by the time I get around to getting some coated and shot. It is still hunting season here, and I've still got an elk tag. Then there will be much holiday travel! Thanks again for the heads up, Yondering. If I can do what you're doing...I'm excited to find out!

Dang Nab it Yondering, I'm old and set in my ways! Been pan lubein' for over 60 yrs., but, ya done sparked my interest! Guess I'm gonna have to break down and try something new. I also ordered a lb of the yellow/green, as seen in your post.
Thank ya kindly for starting this thread. I'm sure that many will benefit from it.

Well, you can still pan lube too, if you want. I do, for one particular hunting load, that for some reason leaves lead rings in the chamber with dry powder coat, or bare lead lubed. With lubed powder coat though, it shoots great. Probably because I'm not hardening the bullets; keeping them soft for hunting.

I can't really say if it's the color, or some other different characteristics of the different powders, but every color I've used acts a little differently. They all work, although some like the Harbor Freight stuff are pretty poor, but that particular green is the best I've tried. It coats nicely, with a slick finish, and doesn't pull too much coating off the bullets when breaking them apart.

Another tip - let the bullets cool completely before breaking them apart; if you do it when they're warm, it leaves larger bare spots on one of the bullets.

I just wanted to thank you for this thread.

I just finished my first batch of grass green bullets. I had a bunch of 358 158 grain GC's and 200 grain GC's, and followed the instructions as best I could.

I have two differences. I tried with airsoft pellets and without, and I found the with-pellets batch had better coverage. I also tumble lubed after sizing.

The 158 grainers are going in 357 Mag loads for my lever. The 200 grainers are bound for the 35 Whelen.

Do you mean you powder coated after sizing, or you tumble lubed in something like LLA after coating? You shouldn't have any reason to tumble lube powder coated bullets; part of the big advantage is they don't need any other lube, and don't leave any mess in the dies.

Sizing before coating is not ideal; some people do it but there's really no benefit, and the end product is not as good. Sizing after coating irons out any uneven spots in the coating, and makes every bullet the same size and round.

The airsoft pellets are also an unnecessary complication IME, since you have to pick each bullet out, instead of just dumping them out in the tray.

You aren't looking for a thick heavy coat of powder in one pass; two thin layers give better results with smaller defects. If you can't get an adequate powder layer, like my 2nd and 3rd pics in the OP (those are the second coat), you may be using a powder that's not ideal, or not shaking well enough. A gentle swirling around doesn't cut it, shake like you're trying to kill what's inside, for a good 20-30 seconds.

1) I coated (w. airsoft pellets)
2) I cooked @ 400 for 10 min
3) I coated (w. airsoft pellets)
4) I cooked @ 400 for 10 min
5) I applied gas checks and sized
6) I tumble-lubed with Alox

The paint I used is the exact paint you suggested in the OP. Grass Green?

I'd read somewhere such that #6 improved velocity, but I'm just getting started. I'll try without #6 next time out. I also went back and tried to find the reference to tumble lubing PC's and could not find it. Who knows? Maybe I just dreamed it.

I would agree that the airsoft pellets appeared to be unnecessary. I just had them around, so I thought I'd throw them in. You're right. I figured the pellets would sift out, but they stuck in the mesh with the bullets. The good point about the pellets is the first coat with pellets was a bit smoother, but you could not tell by the time the 2nd coat was applied.

I have an answer on this point, from a PhD in Chemistry no less. My buddy is getting into PC and bullet casting for his 458 SOCOM. I showed him this thread. He's using the Harbor Freight sprayer, and I thought this might be easier for him.

He pondered the idea of how the different colors work, and said it made sense. He said that if you assume the only difference is the coloring agent, then the difference is down at the molecular level, and different sized molecules would either impede or promote bonding with the lead alloy.

The grass green paint probably has Titanium as a major constituent of the colorant. I suppose there is something to be said for coating your bullets in Titanium, huh?

BTW: My buddy is now experimenting with Krylon spray paint as an alternative.

Cool, titanium bullet coatings. I like it.

The "grass green" name I used was incorrect, it's actually "yellow green", per the first pic above. There is also a grass green that is a slightly different shade, that might also work well. A friend used "Kawasaki Green" also from PBTP with good results; it was a bit brighter color.

I experimented with various types of paint before discovering dry tumble powder coating. I tried regular Krylon, expensive epoxy paints, high temp engine paints, and a bunch of other stuff, but never found anything satisfactory. FYI you do need to recover the bullets to read the whole story.