What temperature for powder coat?

[ThomR]

I've been baking my powder coated bullets at around 400 degrees up until today. Today I happened on an Elvis Ammo video where me mentioned baking the bullets at 275. The reason for the lower temperature is so the bullets don't stick together. So, I went to my garage and cast a few .380 bullets for my wife's new pistol. I dumped them in some Smokes carolina blue powder, and threw them in the oven on 275. The powder melted just fine, and they didn't stick together at all. I will be baking bullets at 275 from now on. Gone are the days of throwing bullets back into the melting pot because I couldn't get them to break free from each other.

[sureYnot]

I saw that video too. Not recommended for HF red.

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[bangerjim]

They may “look” good but - - - did you do a hammer test?????????

Hammer test = Pounding a coated boolit into a small cube and ZERO powder flakes or come off.

That is the REAL test.......not some video on the net.

Why do professional powder coatings recommend ~400F? Because it works - and the powders are engineered to perform the best at that temperature.

I never have had boolits stick together in over 4+ years of coating. You may want to explore alternate coating methods if yours allows boolits to pile up on each other during the baking process.

Good luck at that very under-temp process.

Bangerjim

[Kraschenbirn]

I'm with Bangerjim. I've stuck with Smoke's recommended method from the day I began experimenting with PC and NEVER had an issue with coating coverage or adhesion. MY recovered .30 cal. boolits, fired at well over 2000 fps, retain 80%-90% of their coating after passing through a 1/2" of plywood and 8"-10" of dirt. Ain't broke, don't fix it.

Bill

[Grmps]

Different powder manufacturers recommend 385° (rarely) 400° (99% of the time) and occasionally hotter for specialty powders.
many recommend baking for 10 min AFTER the powder starts to flow, I do most of mine for 15 min after putting them in the oven (** I cover the bottom of my ovens with ceramic BBQ briquettes so they return to temperature alot faster after opening the door**)
I have some specialty powders (like chrome) that require 20 min after the PC starts to flow.

I do not know the specifics on PC and baking, but with HiTek coating, the boolit needs to reach a certain temperature for a certain amount of time to properly cure and 400° for 10 - 12 min (depending on the efficiency of the oven) achieves that.

I'll be interested to see pictures of your hammer test, "pennies lengthwise and widthwise and a cube to see if you get flaking. then report back to us about barrel condition after shooting a batch.

[ThomR]

These are 95 grain 380 bullets I cast yesterday and powder coated at 275 for ~15 minutes. I'm still new at powder coating. Please let me know if these look acceptable. This is using Smokes Carolina Blue with a little bit of Eastwood pink thrown in.

[ThomR]

Here is a zoomed in image on one of the bullets.

[slide]

Shoot some of them and see how they do! Sorry Grmps, didn't see where you posted the same thing.

[Grmps]

does the PC scrape off the edges with your fingernail? No worries slide, just double impressing that shooting is the ultimate test.

PS if you hammer them into a cube you have more corners to show possible flaking.

[bangerjim]

does the PC scrape off the edges with your fingernail? No worries slide, just double impressing that shooting is the ultimate test.

PS if you hammer them into a cube you have more corners to show possible flaking.

Cracking due to lead expansion/movement is one thing. Flaking is totally another thing!

I use the hammer test to a cube as my ABSOLUTE FiNAL test for perfect PC coating/curing. Cracking due to lead movement is another thing all together.

A good cure of PC should not flake (unlike the Senator Flake we have here in AZ!!!!!) and proves the total and perfect adherence of the PC material to the alloy substrate.

Bangerjim

[ThomR]

I hammered one of them into a cube. After hammering it into a cube I tried to scrape powder coat off with my fingernail and couldn't get anything to come off. The 380 dies that I ordered are supposed to be delivered today. I'll try to get some loaded in the next couple days and run out to the range. I hope I can recover some of these bullets to see how the powder coat performed.

[ThomR]

I went out and shot some of my low temp powder coated bullets earlier. They shot just fine and didn't leave any deposits in the barrel at all.
I will continue to experiment with this method and see how it works in the future.

[bangerjim]

Glad you are playing around with that. It may help someone on here.

I personally will stick with 400F. Baking at a much lower temp gains me absolutly nothing.....the oven is doing all the “heavy lifting”! 275? 400? Whatever floats your boat. I have never had baked boolits stick together like you describe. They just don’t touch each other on the racks. I rarely ASBBT boolits any more. I use my 2 ESPC guns to get perfect smooth even coats every time.

Thanks for your testing info.

Bangerjim

[ThomR]

Glad you are playing around with that. It may help someone on here.

I personally will stick with 400F. Baking at a much lower temp gains me absolutly nothing.....the oven is doing all the “heavy lifting”! 275? 400? Whatever floats your boat. I have never had baked boolits stick together like you describe. They just don’t touch each other on the racks. I rarely ASBBT boolits any more. I use my 2 ESPC guns to get perfect smooth even coats every time.

Thanks for your testing info.

Bangerjim

I may switch to a double bake method. I will do a rather large batch at a low temperature so they don't stick together, then stand as many up on a tray as I can and bake them at 400. This way I don't have to worry about the fresh powder getting all over me, and the bullets get a perfect coating that is cured properly.

[ThomR]

The load I tested earlier was in a Smith and Wesson M&P 380 EZ. 95 grain bullet over 2.3 grains of red dot. They were just a hair milder than factory 380 loads.

[Beagle333]

My powder directions say 400°, so I use 400°. But I don't bake in a bulk pile, so I don't have any benefit from trying other temperatures. If it is truly working for you, congratulations and thanks for sharing. Have fun with it! You only have to please you. That's why I spray instead of tumble, I'm a picky old guy about my work, but I only have to please me. Happy shooting!

[Dragonheart]

To assure the necessary cross linking of a polymer the manufacturer of the powder establishes a cure schedule meaning a certain amount of time at a certain temperature applied to the polymer to acheive cross linking. When cross links are added to long molecules, the flexibility decreases, the hardness increases and the melting point increases as well; all very important to the properties of the polymer jacket of a bullet.

Like banger my concern is making the best PC bullet I can, so I will stick with the recommendations of those that make the powder, but to each his own.

[sureYnot]

I went out and shot some of my low temp powder coated bullets earlier. They shot just fine and didn't leave any deposits in the barrel at all.
I will continue to experiment with this method and see how it works in the future.

Are you able to determine any difference in BHN between those baked at 275° vs 400°?

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[ThomR]

Are you able to determine any difference in BHN between those baked at 275° vs 400°?

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I never check for BHN.

[slide]

Thomr, you will probably be alright shooting the low temp bullets in pistol. Check out the other video where Elvis shoots the low temp bullet in rifle. It didn't work real well. I am not cutting Elvis down. He stated at the start of the video that he didn't know what to expect and that everybody including himself would see. That takes guts. He does a lot of experimenting and is not afraid of failure. One thing I really like about the guy is that he is not constantly asking for money like a lot of them. Sounds like a bunch of tv preachers.