Powder coat fire lapping

[donhuff]

I have thought about this a few times but never pursued it as I did not need to lap anything since starting to PC. But another fellow I know might have the need to fire lap, so I'm thinking about it again.

This is NOT, a question about if you think fire lapping is a good idea or not. That's for another post in another section.

I'm thinking that if we had a dry powdered abrasive of some sort, that could be mixed in with the powder, and either tumbled or sprayed onto the lapping bullets. That would make for a much neater and more positive way of getting that abrasive into contact with the bore that needs lapping. It "should" be much better than rolling slugs in an oily abrasive, and mashing a few of the grits into the lead. Every time I have done it that way, seems like I can get only a few grit per bullet to lock into the lead.

I have 5 lbs of red iron oxide, some copper oxide, manganese dioxide, but all these are 325- 600 mesh, and I think too fine to do any good. Also, I know the RIO is a pretty mild abrasive as I use it mixed with oil and put it in the action of my Rossi lever guns when I'm doing the initial break-in process. And it puts a really mild slick polish on the moving parts.

Any ideas as to a good abrasive? I'm guessing aluminum oxide would be the one to get. And what do you think about the idea?

[StromBusa]

I was thinking about it as well...these guys sell coating or powder for that purpose.

http://www.davidtubb.com/

[bangerjim]

I have never had much luck getting foreign materials to mix with PC powder and then cure properly and adhere right (pass the hammer test).

If anything, I would thing silicon carbide dust would be what you want. My lapidary supplies have that powdered material from 100 grit all the way to 1,000 grit.

I have no idea if it will mix and cure with PC. We will have to go to school on you, I guess.

banger

[dilly]

It "should" be much better than rolling slugs in an oily abrasive, and mashing a few of the grits into the lead. Every time I have done it that way, seems like I can get only a few grit per bullet to lock into the lead.

Isn't that preferable in a process that can't be reversed? I mean if you remove material you can't go back but if you do it a little at a time you can stop at the sweet spot. It's easy for me to imagine a much more abrasive powder coated bullet by this method, and it might possibly be too effective. You sound like a pretty smart guy and know the process better than I do, but I guess I would just say to be cautious not to overdo it, especially on a buddy's firearms.

For initial tests I would think some kind of handgun with an easily replaceable drop in barrel would be a good place to start in case it doesn't work out just right.

Regardless, I'm interested to hear your progress and how it works out. Please report back and let us know.

[DougGuy]

For initial tests I would think some kind of handgun with an easily replaceable drop in barrel would be a good place to start in case it doesn't work out just right.

If this is a Ruger revolver you sure ain't gotta worry about the barrel going away in just a few rounds. If it's stainless, even 4x tougher to firelap.

[donhuff]

bangerjim,

Not to worried about it passing the "hammer test" as long as it stays on till it gets in the bore. Then it will do it's job. As long as it would mix well enough to be sprayed and adhere until it was baked, then it would be locked in so to speak.

[donhuff]

dilly,

The gun in question is a rifle, but it's real easy to not over do it. You just have to check it often. Like douguy sez, you really ain't gotta worry bout over doing it.

Last one I did was a rossi 44 in stainless. I think I shot 100+ grit rounds through it, before I was happy with the results. Sure is slick now.

banger, the silicon carbide sounds good to me. I'll look it up. I might try some of my oxides too, just to see if the concept is worth the effort of going further.

[bangerjim]

Any local rock shop (lapidary supplies) should have a good selection of lapping/polishing compounds in Si carbide and Al oxide.

Check them out!

banger

[DougGuy]

Well, (click click) with the equipment used for PCing, and abrasives, and rolling boolits between steel flatbars, it sounds to me like putting abrasive in a bead blaster may just do a neato trick for getting it on the boolits? Either bead blasting bare cast boolits and shooting them as is, or spraying with PC and then lightly spraying abrasive on the wet boolits before they cure might work.

[bangerjim]

Most of us "spray" PC on with ESPC guns.................dry. There is no wet involved here. I do not think there are many left that use the piglet method anymore. The abrasive would have to be mixed with the dry powder, applied with the ESPC gun, and baked into the coating.

From the many experiments I have done with PC'ing, anything in the powder will kill or severely diminish the static attraction to the boolits. Again, this will have to be tried by someone out there, as I have no interest in doing it for anything I own.

Si Carbide is VERY heavy and may not be conveyed by the fluidized bed action in the ESPC guns. Powder is VERY light!

banger

[dilly]

What about a dry tumble application?

[bangerjim]

DT is even MORE static sensitive than ESPC!!!!! Many have trouble getting just the bare powder to stick, let alone contaminating it with an abrasive. And as I said, carbide is very heavy and will just lay in the bottom of the bowl. I know for a fact that graphite and moly totally KILL the static in the BBDT method. That's why manufacturers put it in gun powder!

But try it. If you are lucky enough to get the standard BBDT method to work in your damp/wet climates, mabe adding contaminants for abrasion might work.

Let us know. I personally do not have the time to waste experimenting with something I will never use.

banger

[MT Beard]

The way I powder coat my jigs and lures that are multi colored is with a small airbrush. If you mix the powder paint with lacquer thinner it will dissolve and allow you to spray it on wet with the airbrush. Before you bake 'em you have to let the thinner evaporate completely! If you don't it will out gas while in the oven and create many fine bubbles in the cured powder coat, ask me how I know. It would be very easy to spray the bullets with the lacquer thinner / powder coat and then dust them with abrasive. Would be especially easy if you also have an airbrush set up for abrasive etching. The powder coat remains sticky for quite some time, so you would have a good time window for applying the abrasive. Let them sit for quite awhile before baking!

[C. Latch]

Would it be possible to spray a dusting of abrasive dust while the PC was melted during the curing process?

[MT Beard]

I'm pretty sure that would also work. But, then you would need to pull a hot tray of hot bullets out of the oven, dust 'em, and put them back in. I'll bet it would work just fine, just seems like it would present more opportunities for mishaps. At least for my clumsy self that is.

[RP]

Would it be possible to spray a dusting of abrasive dust while the PC was melted during the curing process?

I was thinking the same thing just never fire lapped anything before so my ? would be how much do you want on your bullet? and would you need to size them ? I know when the PC is hot it is very sticky and I feel for sure that just a few mins in the oven it would be time to add the fire lapped material of choice then finish baking to bond it together more.

[mwc]

I think that a person may try and roll hot out of the oven pc'd bullets in some of the abrasives mentioned, as the pc is still soft at this point and the silicone carbide might just embed enough to work.

[HollowPoint]

Slightly off topic but not by much.

I experimented with this type of lapping but not with PC coated bullets. I used hot-melt-glue bullets instead.

What I did was to put a very thin film of WD-40 on the cavity walls of my bullet mold and then sprinkle or dust a layer of my powdered lapping compound onto the surfaces of the cavities. I can't remember the name of the compound. This was some time ago.

I just bumped the mold against my work table and all the excess lapping compound fell away leaving a very light film of compound where it needed to be. Then I injected the hot-melt-glue and I got some perfectly shaped abrasive bullets. The mold had to be heated before injecting the hot-melt-glue.

The good thing about this method was that I didn't have to drive all the way to the shooting range. Depending on the length of your barrel, only a very, very small charge was needed. I did mine in my garage. I just shot into a bundle of shop rages.

The barrel I was trying to salvage was on an old Enfield rifle. It Did Work but, the barrel was to far gone to make any difference. I would have had to lap it down to a smooth bore to get rid of all the pitting.

HollowPoint

[DanOH]

Tell your friend just to use HF flat black.
EVERYODY KNOWS that stuff will strip the rifling out of your barrel in short order....wink....

[HollowPoint]

Tell your friend just to use HF flat black.
EVERYODY KNOWS that stuff will strip the rifling out of your barrel in short order....wink....

I think that this "Harbor Freight Flat-Black Powder Coat" is just another of the many "Old-Wives-Tales" we come across in the shooting sports. Since Powder Coating is a relatively new thing, it's more of an up an coming "Old-Wives-Tale."

The same thing is said about aluminum gas-checks and such. If you shoot your guns long enough, even conventional bullets will eventually wear out the bores.

A guy could die of old age before shooting enough Flat-Black Powder Coated bullets to make any measurable difference.

HollowPoint