Powder coating question

[SierraHunter]

I'm just starting to play with the PC world. So for, I've only tried the Harbor freight Red so far baked for 20 minutes at 400 degrees, and although am getting decent results, am having a few problems.

First problem. My bullets are starting life at .309" (200gn NEI DD). After coating I'm running them through a .311" lee die, and it's peeling my PC off at the base of the bullet. I'm I not baking hot enough? Do I need better powder.

Also, are you guys installing gas checks before or after?

 

[David Reiss]

Haven't done it enough to answer all your questions, but with the coating you don't need gas checks, that I do know.

 

[SierraHunter]

I just pulled another batch out of the oven (this time 130gn NOE hollowpoints) I baked them for 25 minutes at 450 this time. Still a bit too hot to touch. I installed gascheck before baking. I'm getting light leading without the gas checks with subsonic loads, so will want the gas checks I think with super sonic.

 

[yodogsandman]

I electrostatic spray mine and stand the bullets up in holes drilled to fit the gas check shanks on a 1/2" thick aluminum plate. The GC shanks are left bare that way and I attach the GCs after.

Are you using the "shake and bake" method? Most guys will seat and size GCs before PC using that method. Otherwise, the GC shank will be too large to seat them well.

You might be getting the PC too thick on the bases. It might be melting down while curing, too. Try running a few through the Lee sizer die base first.

Do they otherwise pass the "smash" test?

Are you using an oven thermometer and curing them for 10 minutes after the oven reaches 400*F? Using a convection oven?

These are NOE 269-163 bullets stood up on the plate. Notice the non stick aluminum foil.

 

[David Reiss]

If you are getting leading, I think you a size issue. Check that before you rely on the GCs. Many of the rifle CBs I shoot under 1800 fps, whether PB or GC I get no leading. Most of the time I do not use GC unless needed. If you get leading with subsonic loads, you will probably get leading with higher velocities even with the GC.

 

[David Reiss]

Any PC bullet I have shot has been PB or without the GC and have not had leading issues. I experienced the same problems with the PC being to thick until I started spraying it on.

 

[SierraHunter]

That's a good idea with the aluminum sheet for the gascheck shank.

I've tried base first and they seem to get more of the coating scraped off that way.

Have not tried the smash test...hate wasting perfectly shootable bullets..

I'm letting the oven preheat, but am just using the dial. 20 minutes in a old propane oven out of a camper.

 

[gman]

Here's what I do. I seat my gas checks and size to the diameter I need. I do this because on several revolvers I need fat bullets to fit the throats. I just got in the habit of doing this for everything I pc. If plain base I still size first. I purchased my powder from smoke4320 over at the CB forum. Never used Harbor Freight powder. I do believe the better quality powder is worth it but like I said I do not have experience with the HF powder. Once coated my bullets go in a pre heated oven at 400 deg. Once the temp gets back to 400 I time for 10 minutes. I then run them through the sizer again. I have had no problems with the coated scraping off or peeling. One thing to make sure is that your bullets are free of any oil or grease (lube) before you coat them. I'm using my older lyman 4500 that has been cleaned just for pc'd bullets. My dies were made by Buckshot from the CB site and are super smooth inside. I have tried to run some through my NOE push through's but they will scrape the coating. Doesn't take it of but scratches them up. May not make a difference but I just don't like it. I'm sure Ian or others will chime in. I still use gas checks on the loads I'm pushing hard. But I have pushed some cast weighing 308 grains in my Ruger Bisley just over 1250 fps plain based. With the pc I'm getting higher velocity with lower powder charges or if using the same charge weight as lubed velocities will be higher. Good luck!

 

[SierraHunter]

I'm running them to the same size I make them with regular lube.

If you are getting leading, I think you a size issue. Check that before you rely on the GCs. Many of the rifle CBs I shoot under 1800 fps, whether PB or GC I get no leading. Most of the time I do not use GC unless needed. If you get leading with subsonic loads, you will probably get leading with higher velocities even with the GC.

 

[yodogsandman]

You need to get a cheapo oven thermometer at Wally World or wherever. I use a convection toaster oven found while out yard sailing for $6. Better heat control.

 

[SierraHunter]

I'm thinking my coating is not baking on well enough. The bullets are going straight from mold to the powder. I'll see how this batch does that I baked hotter. I'm actually running them though a sizer. 002" bigger after PC and it is scraping off. Also have problems with it scraping on when seating, unless I heavily bell the case.

 

[SierraHunter]

You need to get a cheapo oven thermometer at Wally World or wherever. I use a convection toaster oven found while out yard sailing for $6. Better heat control.

I've got a meat thermometer. Will that work of I leave it in the oven?

 

[SierraHunter]

This is the batch I just pulled out.

 

[gman]

Really need the oven thermometer to verify your oven setting. And I second the convection oven statement. I have seen thermometers that should not have been placed in a hot oven explode when the door opened and rushing air hit it so be careful there.

 

[SierraHunter]

I might get a convention oven when money is better. I just had to put 250 bucks into one truck, and the other one still needs 400. Will be awhile yet.

 

[freebullet]

Need the thermometer.
It sounds like undercooked. You can overcook the coating too. Don't shoot the undercooked bullets not only will they lead your bore they will powder coat it to. It's really difficult to remove, trust me. 1" per hour of barrel to clean out.

What size do you want your final bullet to be? What size lead bullet does it shoot well with standard lube?

 

[yodogsandman]

I'm thinking my coating is not baking on well enough. The bullets are going straight from mold to the powder. I'll see how this batch does that I baked hotter. I'm actually running them though a sizer. 002" bigger after PC and it is scraping off. Also have problems with it scraping on when seating, unless I heavily bell the case.

Yep, you'll need a bigger neck expander die, too.

This is the plate before being covered. The 1/2" thickness weighs enough to prevent bobbling it when moving it around and is a good conductor for the ground wire.

 

[gman]

We have all been in that boat before I'm sure SierraHunter. For the time being try to get a oven thermometer. That will help you knowing for sure what your oven temp is really at.

 

[Rick]

Heed the advice about the oven thermometer. The thermostats on those propane RV ovens are horrible, temp swings can easily be over 100 degrees. I started heat treating bullets with such an oven and I had to baby sit the thing and cracking the door to relieve heat.

 

[Ian]

Ok, couple things.

First off Harbor Freight powders are epoxy powders, are pretty low-quality, coat too thick for a lot of things, and like all epoxies are a lot more brittle than the Polyester powders most of us use. Inability to flex can cause leading as more lead is exposed when the engraves cut into the bands.

Second, there are two reasons I do not spray my powder, but instead use the Airsoft bb shake/bake method: Spraying can and does put uneven thickness on critical areas like the side of the nose, and sprayed powder doesn't adhere nearly as well as impact coating does. If you dust the powder off of an impact coated bullet before baking, you'll notice that the surface will have a bead-blasted appearance due to the powder abrading the soft lead oxide coating and texturing the base metal. Possibly for this reason, when using Polyester TGIC powder, the coating usually adds only about one to one and a half thousandths of an inch to the bullet's girth.

Third, I've found out so far that most of my rifles and handguns like their PC fodder to be about halfway in between what I'd normally size them to and what nominal, jacketed bullet diameters would be. For .30-caliber, for example, .309-310" covers the bases, depending on throat entrance diameter and neck diameter.