Powder coating first attempt.

[BRatigan]

Ok, I made the leap into PC. I have studied many videos and acquired the powder(Eastman) and some old 375 #2 lead 245 grain bullets from the nineties that I cast back then. I purchased a B and D natural convection oven, the smallest available and a temp gauge for in cabinet use.

The temperature gauges of course did not agree with each other, off by 75 degrees. At what I thought was 400 degrees turned out to be much higher than that. After about 13 minutes the bullets began to melt and ooze. I yanked them and quenched them. I did notice that the PC began to melt rapidly when I put the bullets in the oven. The parchment paper went brown. After quenching I did a smash test and found no flaking. The bullets were coated well, that was not a concern. The shake and bake method worked perfectly even in a smallish number 5 container. I did manage to actually size the least deformed bullets that had no real upset and they sized to .379 easily from .381 as cast. I used my Lyman number 45 lubrisizer without pressure from the lube reservoir.

My observations lead me to conclude that a small oven will produce more concentrated heat and therefore can be run cooler than the dial indicates and for a shorter time. I can adapt and will experiment when my dies arrive next month. I think Elvis is on to something regarding time and temp. Oven cabinet size I believe needs to be accounted for. Below are some pics.

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[mehavey]

1. Forget the oven temp dial.
2. Don't use a mechanical temp gauge either. Get/use an inexpensive digital (https://buythermopro.com/product/tp-16/) grill probe on same rack as bullets.
3. The oven will take a least 10 minutes to equilibrate. Until then, the burners will be going full blast/direct heat on anything in the oven = "melt"
4. Don't put bullets in until Temp probe show temp starting to drop below 450
5. With Eastwood powders, run the timer to 30 minutes to accommodate 10 minutes bullet heating/then 20 minutes curing.

ps: Make sure oven's on "Bake" (not broil ;-))

[BRatigan]

Thank you mehavey I will make some adjustments. I did preheat for 20 minutes. I'll get it. This was successful on some fronts so I can learn, adapt and move forward.

[405grain]

The parchment paper will turn brown when you bake on the powder coat. This is normal. I even use the same piece of parchment paper 3 or 4 times until it gets too crispy. Nothing sticks to it, so you can use it over and over if you want. The factory tray in my El Cheapo powder coat toaster oven was just a flimsy piece of really thin sheet aluminum. This flexed when I put in a load of over 100 bullets, so I replaced it with a piece made from 1/8" aluminum plate. Not only will it handle a heavier load, but it heats up more evenly that the thinner tray.

[Charlie Horse]

I made baffles/shields in my little oven so that the heating elements don't radiate directly on the boolits. They make all the difference.

My dial is off 50 degrees too hot. My first try gave me colored puddles.

[cwlongshot]

Here is my methods.

https://youtu.be/vzSMkpf5SCY

CW

[BRatigan]

Ok, after trial and error I have found what works for my condition. I lowered my temp to 400 from 475 on the oven and yes I know they aren't accurate and my other thermometer doesn't match. I got past that. I run the oven at 400F for 10 minutes and then "bake" at 375 for 13 minutes. I have coverage, adherence and nice looking bullets. The picture below are bullets fresh after being quenched and dried. These are my 230 grain .452 purple people eaters for my 1911. Again these bullets were salvaged and pulled 30 years ago. I delubed and brushed the bullets to get all the crap off. I am happy with this result. Eastmans Ford Dark Blue and Signal Red about 50/50 mixed.
The blue alone didn't perform as well but did great anyway. One of the blue bullets had contamination in the lube groove so no sticky there.
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[405grain]

BRatigan: You should follow the manufacturer's recommendations for both temperature and time of bake for the powder coat. The powder will get shiny and might look done at lower temperatures or shorter times, but there's more going on than just melting the powder. The polymer in the powder coating has long chain molecules that need to react to the temperature and bond, both to the bullet surface, and to each other. One of the mistakes guys that are new to this do is assume that as soon as the bullets are smooth and shiny their ready. If the polymer isn't fully cured the coating can cause powder coat to smear inside the bore, kinda like a plastic version of "barrel leading". 375 degrees for 13 minutes might not be long enough. A better cure would be 400 degrees for 25 to 30 minutes. Go ahead and shoot up the bullets that you've already coated and see how they work.

Also note: When you powder coat a cast bullet it can add up to .002" to it's diameter. After a bullet has been powder coated you can usually run it through a bullet sizer without needing any lubricant. For bullets that fall from the molds a little oversized, I run them through a push through sizer before powder coating, then run them back through again after applying the powder coat. Some type of lube is usually needed to push the bare lead bullets through the sizer. I use a pad that has liquid dish washing detergent on it to lube those cast bullets, as the "lube" will completely wash off prior to powder coating.

[BRatigan]

Thanks for the input 405grain. I'm experimenting and I know there will be failure that I can learn from. I've got a lubrisizer to size the lead and coated before they get loaded. Testing of the bullets on the range will tell me a lot more. I like the process and after some 35 years reloading and casting early on, the coating aspect has me intrigued.

[mdntranger50]

I have a smaller oven and find the low heat method works well for me. I only PC batches of 150-200 9mm at a time though. I use Eastwood and PBTP powders. In my testing the low heat method passes the smash test and digging projectiles out of the dirt berm to examine.

[BRatigan]

I've got my technique down to where I am happy. Now on to bullet hardness to determine pressures, fps and loadings. I tried to pencil test with good results and will verify with a Lee hardness tester on Wednesday. After a week or so I noticed that the bullets actually got slightly smaller in diameter. That will make sizing a bit easier also. Next step after that will be range time and then I'll post targets.

[BRatigan]

I tested my alloys and found I have 25 pounds of alloy with a BHN of 20 and 50 pounds of alloy with a BHN of 13. Next week I will test the alloys again to see if they change with time. One batch of 20 pounds was wheel weights with a side of spare soft lead bullets. My main batch I have been using is BHN 13 also. The hard alloy I got from my local reloading store. He melts down range scrap etc and makes ingots. I should be covered for most of the casting I will be doing. The coated bullets size beautifully to .358 and I'll test my Unique 6 grain load on these 150 grain hollow points from my El Patron 357 mag tomorrow. I'll get chrono data as well. This should be fun.

[pworley1]

There is always a learning curve. It looks like you are off to a good start.

[BRatigan]

(This is a copy of a post I made in the molds thread). Range day indicated that I was achieving velocity within a few fps. Group was somewhat open at 15 yards and I suspect slight wobble in my target results from my 4.75 inch El Patron. My test pilot next to me tried the same load in his Ruger Security Six. His bullets went in sideways so I know the bullets are undersized at .358. Next test will be in the Win Model 73 to see if I have similar results. I can easily up size these by sizing first and coating to get the extra 1000th or not size at all and coat. I'll post more as I get results.

[BRatigan]

Went back to the range today. I brought my Win M73 and my El Patron. The M 73 liked the coated bullets, showing great promise, no wobble or keyhole. The El Patron loved the as cast .3595 lubed in LLA one coat. Shot well as a starting point. It leaded badly just at the start of the rifling for a half inch. The M73 shot this same bullet into an inch or so at 50 yards. It was amazing but it also leaded badly just at the start of the rifling. Brinell #12-13 pressure at 17800 psi. Should I back off the load?

[Smoke4320]

leading with pc indicates powder not properly cured .. correct Time and Temp are critical to good pc coating without leading
an actual oven temp of 400 degrees for 20 minutes min on small bullets. Longer on larger/heaver bullets. 350 gr 45/70 may take 30 minutes on more
also a convection oven with fan on with give you a more consistent temp throughout the oven (eliminates hot and cold spots)

[BRatigan]

Sorry if I wasn't clear. The pc'd bullets did not create the leading problem . It was the same bullet, uncoated and unsized that leaded. The coated version is going to be fine. The as cast bullet though leaded in both guns. I checked the data and with the hardness I'm shooting, it looks like I'm overpressure with my load. I'll back it down and retest. Even at 1200 fps I think this bullet will be fine uncoated and very accurate. I'll get 1500 fps coated. Should get good accuracy.

[hc18flyer]

Smoke- Should I start my 20 minute timer once the oven gets back up to 400 degrees? I have an oven thermometer, some times it takes several minutes to get my convection oven back up to temp after I place my tray of 200- .38 Special bullets in the oven? I have not had any problems yet, but know I know to run my .458-405 grain bullets longer. hc18flyer

[Smoke4320]

I would say yes.. Its like this there is NO issue with cooking longer as long as you oven maintains a fairly consistent 400 degrees. The problem comes in when you have wild swings in temps especially if it exceeds about 420 degrees or drops to much below 380 for long.

The other method is to put bullets in oven and watch closely when powder glosses and starts to flow cook at least 15 minutes at 400..again bigger heavier bullets leave in longer

overcooks (time wise) at 400 degrees will not cause issues .. cooking at less than 400 or not long enough can cause issues

every customer issue we have had where they had leading issues it came back to not at 400 or not long enough,... EXCEPT 9MM There are some 9mm's that can be a bugger to figure out usually having to go to .357/358 sizing to fix issues

[charlie b]

Went back to the range today. I brought my Win M73 and my El Patron. The M 73 liked the coated bullets, showing great promise, no wobble or keyhole. The El Patron loved the as cast .3595 lubed in LLA one coat. Shot well as a starting point. It leaded badly just at the start of the rifling for a half inch. The M73 shot this same bullet into an inch or so at 50 yards. It was amazing but it also leaded badly just at the start of the rifling. Brinell #12-13 pressure at 17800 psi. Should I back off the load?

Have you used LLA much? It needs to be thin coats. Two or three coats. Cured for several days. Should just barely see the color change from the lube. Even then you might see leading depending on gun, bullet and load.

I always had trouble with LLA above 1100fps. That is one of the reasons I went to powder coating. Before that I pan lubed and lived with the mess.

Now I also have a lubesizer. Sometimes I use it, sometimes I PC. Depends on the bullet, the gun and the vel.

[BRatigan]

Have you used LLA much? It needs to be thin coats. Two or three coats. Cured for several days. Should just barely see the color change from the lube. Even then you might see leading depending on gun, bullet and load.

I always had trouble with LLA above 1100fps. That is one of the reasons I went to powder coating. Before that I pan lubed and lived with the mess.

Now I also have a lubesizer. Sometimes I use it, sometimes I PC. Depends on the bullet, the gun and the vel.

I am very new to LLA. Its possible I used too little but it smelled like a crayola factory when I was shooting so I probably used enough. I just did a batch this AM. P Coated and then sized to .3595 and another batch sized to .3595 and traditional lube from my old Lyman 45. I will use two different loadings of Unique for these; the coated bullets will get 6.3 grains that match an awesome load I have for HiTek 158 grain RNFP from ACME. Very accurate and hopefully so with my coating. The naked bullets get 4.3 grains as this will put the pressure at the hardness of these bullets. I'll make harder bullets in the future and can heat treat them also but for now I'll go forward with the above plans. Ill post targets when I get them and hopefully chrono data if its not raining.

[D.Bullets]

First I removed the outer shell. I wired in a Pid $27.00 wired the convection fan up to the on off switch (fan runs continuously when switched on) I drilled the temp probe in from the top. Reinstalled outer shell. 45 cal 230gr will cure about 500 at a time. its now very old but still works great. Here are somesome pictures.

314420 convection fan runs continuously. Wired to switch not heating element
314421 The PID
314423 Temp probe
314422 Temp probe Zoom

[mehavey]

LA much? It needs to be thin coats. Two or three coats. Cured for several days.
....I always had trouble with LLA above 1100fps. Counterveiling view.
One very thin coat.
Oven-dried 2 hrs at 225
Shoot next day.
No issues up to 2,400fps
(You've seen this before: https://castboolits.gunloads.com/showthread.php?368459-223-cast-bullets-w-ar15&p=4472544&viewfull=1#post4472544

That said, I'm a PC convert save for bore riders -- where ALOX is still king.
[smilie=w: