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.

I was under the impression that the plasticised carrier in the paint, was the reason it was able to stick so well after heating and act as a lube/barrier, along with being able to react to static the way it does.

I having been fooling with this stuff the last couple of days. It didn't go so good, mostly explainable as i cast some 45colt bullets where the cheap lee die was not closing completely, and through the diameter off. This had an effect when i ran them through a lyman 450.
I first bought some hi temp engine paint, sprayed them and baked. This seemed to add a couple thousandths diameter to the bullet. I sized them after the paint, and it didn't work so good. Scraped paint off etc. I then stuck some harbor freight paint in a container, and tumbled with the airsoft pellets. it seemed very uneven coverage on the first go around.
didn't bother to bake them, and was reading on cast bullets forum others using different ingredients in the mix, which i haven't tried yet. I think i need to order some better powder, and try again.
Somewhat unrelated, but regarding .45colt. The prewar colt was sized to .454 or even bigger, the postwar colt standardized at .451 or .452. Although i have one smith that the bullet would drop through the cyclinders if sized down that low. I read some stuff last night where people are just sizing to .454 and letting it go at that. Any thoughts from anyone on this? One of my early lyman cast bullet reloading books suggested this as an ideal diameter.
If one were to carry this thought a little further, the nominal diameter today would be around .452. Sizing to .454 and a couple thousandth more for at least the painted/spray version, would get it up there to far i am thinking.

I must have missed where the airlift pellets are added. How many? And when? For the tumbling part?

I have read it both ways the airsoft pellets are not needed, and that they are.
I filled the bottom of the container with them to where they covered the projectile, right or wrong. But didn't like the way they turned out. Blotchy wasn't aware that you coated them more than once.

RoninPhx, don't waste your time with the Hobo Freight powders. Buy the green powder I listed in the OP from Powder Buy the Pound, and you'll have good results following my process. You won't need airsoft BB's, unless you just like making more work for yourself.

Don't bother with the epoxy spray paints either; it doesn't work. If it comes off in the sizing die, it comes off in the barrel too.

Coat before sizing, not after. Use the sizing die to smooth out inconsistencies in the coating.

You need to slug the bore and cylinder throats of your revolver to determine how to size your bullets. Don't just guess or go by someone's standard. Some guns have really large throats, some are very tight, and you wont' know without measuring.

Also, I really recommend a push-through die, like Lee makes, instead of a Lyman 450. The Lee dies do need to be polished inside, but when that's done, sizing is easier and straighter than the Lyman, and faster too. I still have a couple Lyman 45's on my bench, but rarely use them for anything except seating gas checks these days.

i don't have that powder in yet from the place recommended, but i did spray some bullets with the vhs engine block spray.
This increased diameter of the lee .309 170grain flat nose that had come out of the mould at .309 to .311.
I will confirm they went through my sizer die on a lyman bringing them back down to .309 slicker than owl sh*t.
Applying gas checks were easier to.
I can sure see why people are doing this.
If it wasn't that i wanted uniformity in the size, multiple .308 type things to put them in, I don't think i would have sized them either.
Next is to stick them in some 30.30 brass and load not at max but on the upper end and see what they do.
I can SURE see using this powder coat application or the spray paint for that matter, on pistol bullets.
I think that better grade of powder will work quite well.
with the vhs spray, i didn't seem, to have any issues with it coming off.
Traditionally i have used blue angel, alox, or lyman "bug snot" as a lube. Alox works but i have to clean the noses of the bullets after loading. It's hot in arizona. I went in some cases to hitemp lube, it works, but that is a different issue.
I think at this point the paint is an answer in ore than one area.
Let you know when i get that yellow/green paint in and applied on some.

I showed one of the painted projectiles to a 80 year old friend of mine yesterday, that has been casting and reloading for probably 50 years, he got bugeyed and said he had never thought of that. Now at one time he was a IBM engineer assigned to NASA working on the manned space projects. I was thinking, don't they use certain types of paint on the shuttles, and some of the airforce hardware? Same thing.

I took yonderings advice, these are a few after using the powderbuythepound.com yellow/green. Pretty good coverage for just tumbling them in a cup with a lid, doesn't take much and it is better to use less rather than more per coating.
adds about 2/1000th to bullet diameter prior to sizing.
these are lee 310grain gascheck prior to sizing and gas check.
While they are designed for gas checks, i am not sure i really need to size or gas check them.

Yondering, what mould (mold?) make for the hollow points? NOE?

The 9mm and 10mm bullets in the second post are Mihec molds (modified pin on the 9mm), the rest are modified Lee molds. I hollow point my own molds and make the pins to match the application. In my experience, most commercial hollow point molds don't have good hollow point pin shapes.

Looking good!

I would still size them for best results, mainly to make sure they're all the same size, and to iron out inconsistencies or defects in the powder coating layer.

I see the Mihec mentioned now. For some reason I wasn't thinking of them.

I've really enjoyed this thread.

These are .375 winchester. Gulp, using new winchester brass, with a lyman 248grain bullet. They were not powder coated but sprayed with vht engine block paint. I am experimenting so this is just me trying to figure it out. Paint adds about 2thousandth in diameter to the bullet. I sized these bullets naked to .376, would have rather had a .375 die, then painted and cooked. I then resized them to .376, and didn't have any issues with the paint coming off. Went right through the die easy.
I have been messing with some .44 310grain bullets, I did not size them before powder coating, and the sizer die to bring them from .434 or so back to .431 was rubbing some of the paint off.
I should have sized them from the mould to .429, applied paint, cooked, and sized again to .431 which is what i wanted.
I still don't have it down right on the right quanity of powder to tumble with, and i am either getting too much paint, or blotchy .

Can you fire those into something where you can recover the bullets? You can learn a lot from recovered bullets that you wouldn't know otherwise.

BTW you seem to be using "powder coating" and "paint" interchangeably; they are not the same thing.

I had paint rub off my bullets during sizing, when I tried that, but if you have powder coating rubbing off, you either have a rough sizing die or bad powder coating. You should be able to easily reduce the diameter by .010" or more without damaging the powder coat.

If you're using a Lee push through die, it MUST be polished inside. If you're using a luber-sizer press, both Lyman and RCBS dies benefit from a larger bevel leading into the die.

i probably do use paint interchangeably, do know the difference. The paint didn't rub off, the powder coat did.
using lubersizer press and lyman die. I think one of the isssues with my powdercoating is i am getting too much of it on the projectile. translated, i don't have the powder coating application quite right yet. I was bringing the powder coated ones down from around .434 or higher, to .431, definitely more than one thousandth.
I think i am going to fire some of them into some gallon mild jugs which should allow me to capture the bullets.

Some credit to yondering, when you are right you are right.
I took out two cast bullets to fire today.
first one was a 375winchester Lyman mould 375248 at 249grain.
It cast right about that so it was close to lyman no two allow.
I fired this in a marlin several months ago using 23grains of 2400, velocity was right around 1900 fps. Today i used 21.6grains, velocity around 1850fps. First time was a lyman lube, today i had the bullets sprayed with vht red spray paint. I do think it was cleaner, as the barrel is ported. Some months ago got a bunch of powder and debri around the ports, today nothing. I wish i could have recoved the bullet, it went through nine milk jugs and a piece of plywood and kept on going. But there was some mild leading that easily came out. Not totally satisfied, wish i could have found bullet.

The we come to the 44magnum 310grain lee bullet. I powder coated these with the yellow green yonder recommended. I wish i had that part down a little better. However I have a
lyman no 48reloading guide, calling for 2400 on a 300 grain bullet, and minimum of 14grains at 857fps, and max of 15.7 at 1001fps. I loaded some at 15.4grains. was using a thompson contender with ten inch barrel, and a s&w model 29 4inch. I loaded these bullets both with gas checks and no gas checks. It didn't seem to make any difference. The thompson was running faster than the smith, barrel difference. I checked the barrel after firing a number, pretty clean. Later when i officially cleaned the pistol no leading, and very little fowling, extremely easy to clean. needless to say with the ten inch barrel i was getting an easy 200fps over the smith.
the smith ran the same bullets, gas check and no gas check, average velocities right around 1000fps. In the field it looked clean. I fired after these some 44special swaged lead and cast lead and it did lead up at that point as i expected. Below is the gas check bullet as fired through the smith and wesson at around 1000fps. I was pretty hapy with it. It also penetrated nine filled milk jugs and bounced off the plywood backstop. The first three jugs just exploded. The others were ripped until you just got wholes at the rear of the chain. I would hate to get hit with one of these pills. I think it would go through most everything

Looks good! It's hard to recover those flat nose revolver bullets, they penetrate forever. I haven't used the .44/310, but used the .45/300 (which cast at 310) a lot. Great bullet design.

A couple observations:

- That .44 bullet pictured looks like a pretty heavy coat of powder, although it could be just the pic. Try for two thin coats, you don't want too much buildup, more powder is not better.

- That fired .44 bullet collapsed the lube and crimp grooves, and looks like it happened in the barrel not on target. Not necessarily a bad thing, if it doesn't cause problems, just something to be aware of. Your alloy may be a little soft for the pressure of that load.

Did you recover any bullets fired without gas checks? In my experience, they show gas cutting when fired from revolvers (happens when passing the cylinder gap) but not from long guns.

i am sure you are right that they are too thick on the coat. chalk that up to my in experience, didn't recover any of the non gas checked, but both guns were pretty clean prior to me firing the 44special. I will do it again and catch the non gas checked ones. I didn't measure the brinel rating of the alloy, but can. have to think around lyman no 2. I do think i am going to reduce the load next time i load some up.

If they shoot accurately, they are fine. If you want them harder, quench them in water right out of the powder coat oven after the last coat, then wait a couple weeks for age hardening.

I use cool whip containers and no pellets...works great. I just swirl them vigorously for about a minute, dump them in a collator, shake of the excess, dump them on a pan and bake them.

Been doing this for a long while now...have been completely sold since the first batch...and this comes from a LONG TIME conventional luber, but I will not shoot conventional lubed bullets in my guns, again. Matter of fact, I have a lot of them loaded...but they will stay in reserve as a last ditch ammo source.