Powder Coat Hardness

[Traffer]

Hi folks,
I just started to powder coat. One batch so far. Not sure if I am doing it very well yet. I use the pencils for testing hardness of lead. I just had the thought, "hey they use pencils for testing the hardness of coatings in the coatings industry as a standard test, so why not test the hardness of my powder coated bullets with them?"
So here goes:
My first batch tested at 11-12bhn. It is coated on top of 8-9bhn 22lr bullets. So this batch came out noticeably harder than the lead. Plus I had trouble with the coating and it may have come out way softer than normal powder coat. I will test again when I do the next batch and post those results.
Anyone else here use pencils? Why don't you test yours and let us know what you get?

[Smoke4320]

I don't have the figures right in front of me but it should be around 22-26

[bangerjim]

Who cares about the PC hardness!!!!!!!!

I mix my Pb alloy to be where I want it and rely on the PC to provde the lube and seal down the barrel. I am not trying to rely on PC as part of the boolit hardness formula. Neither should you.

But according to some industrial specs, PC runs around 26+ Bhn. Remember that is a 0.002 thicnkess so do not rely on that for boolit hardness.


Just mix your alloy, cast it, coat it, and shoot it. Don't ovethink this simple process. Period.

banger

[rondog]

Pencils?

I have a couple of boolits I coated with HF red, then beat 'em flat with an anvil and big ballpein hammer. The PC didn't flake, peel, or even flinch. That stuff is ON there!

[OS OK]

Now that you are aware of how hard that PC is...your best move is to insure that your oven is exactly accurate and you cook for the required time.
Overthink all you want...how else would we have come to these basic and simple instructions for PC'ing in the first place?
Pencils are a pretty good method to judge the lead you find when you are out and about searching, but...how well 'dressed' do you keep the profile of that lead in the pencil? When it's rounded off at the edge, you are not testing anymore...you are just putting skid marks on the lead.

KISS is a pretty good method to do this casting, PC'ing and loading business...stay at it and enjoy your work at the range.

[Dragonheart]

Yes, a properly cured polymer is much harder than lead. Due to the polymer's hardness, flexibility and bond is the reason you can shoot soft alloy at chamber pressures much higher that the alloy tables say is possible. The polymer jacket provides lubrication, but the polymer's resistance to the short duration of high heat and the torque generated spin-up is remarkable. The alloy tables were designed for lubricated bullets, which is basically a mixture of grease and wax. The lube mixture protects against leading based on the hardness of the alloy and the reason for alloy pressure tables. PC is the future for cast bullets.

[dahermit]

Who cares about the PC hardness!!!!!!!!

I mix my Pb alloy to be where I want it and rely on the PC to provde the lube and seal down the barrel. I am not trying to rely on PC as part of the boolit hardness formula. Neither should you.

But according to some industrial specs, PC runs around 26+ Bhn. Remember that is a 0.002 thicnkess so do not rely on that for boolit hardness.


Just mix your alloy, cast it, coat it, and shoot it. Don't ovethink this simple process. Period.

banger

Who cares about the PC hardness!? It is likely rifle bullet casters/shooters do. The standard for target accuracy (as in The Cast Lead Bullet Association's matches), has been to use pure Linotype...a very hard alloy. While it may be true that in handgun shooting of cast lead bullets, the hardness (especially in revolvers), is not all that critical, shooters of modern rifles may be interested in how hard the coating is in their search for accuracy with a cast lead bullet. Therefore, I would not make assumptions based on only my own interests and experiences.

[runfiverun]

actually we care more about consistency and C.O.R. balanced boolits at velocity more than BHN.
once y'all figure out how to apply a perfect .002 coat your gonna have a ton more interest.

[bangerjim]

Who cares about the PC hardness!? It is likely rifle bullet casters/shooters do. The standard for target accuracy (as in The Cast Lead Bullet Association's matches), has been to use pure Linotype...a very hard alloy. While it may be true that in handgun shooting of cast lead bullets, the hardness (especially in revolvers), is not all that critical, shooters of modern rifles may be interested in how hard the coating is in their search for accuracy with a cast lead bullet. Therefore, I would not make assumptions based on only my own interests and experiences.

If you are relying on PC to compensate for low hardness and poor mixing of your alloy for rifle boolits....I feel sorry for you friend.

PC is NOT a crutch for poor alloy mixing and calculations. Far from it. Some may try to skimp on $$ for Sb and Sn with inexpensive PC, but that is no way to run a ship.

It is only a modern clean substitute for dirty old sticky grease. And adds amazing technicolor hues to an otherwise monochrome world of only silver.

I still mix my alloys for pistols and rifles to what I want as far as required hardness and then PC. The coating allows one to use somewhat softer boolits, granted. But does not eliminate the need for the correct alloy hardness for obsturation and expansion - as determined by one's specific shooting needs.


Good luck with your endeavors.

banger

[Wolftracker]

I'm not an expert on alloys but understand the need for a hard alloy, PC'd or not, at rifle pressures and velocities. Lately, I've been applying PC to pure soft, swaged lead bullets for my 45 ACP. So far, no issues with accuracy or leading. They seem to shoot as well as harder alloyed bullets. They measure .4525 and I have no idea as to whether they obturate but they should, since most of the ones I make have a deep hollow base swaged into them. If it goes where you aim and doesn't foul up your barrel, hardness shouldn't be of too much concern.

[Traffer]

I have already found that PC bullets afford casters the wonderful opportunity to "reinvent the bullet" I mean, with the slickness and durability, there is no need for grease grooves. It allows a larger bearing surface. Discussing details about the hardness may seem pointless but, you never know, it may give someone an idea or give someone the knowledge to break more new ground. Personally I think it is a good thing to know. For me, I found that I have not cured or baked my powder coat properly because it is way softer than it should be. That right there is useful information. With scratch testing, (pencils) now I can see if the PC is being done properly in that measure anyway.
So I say phooey on the nay-sayers. Just phooey.

[Zthomps]

Sense PC acts as a lube and seals to the barrel can you use pure lead sense the PC will make up for the lack of hardness

[RobS]

Sense PC acts as a lube and seals to the barrel can you use pure lead sense the PC will make up for the lack of hardness

Simple answer is no. I have not been able to find a situation where RPM's on the boolit doesn't do the same to a powder coat boolit that it would do to a regular lubed boolit of same alloy hardness. The coating doesn't do magic to a boolit. I have been trying to increase the bake temps on Hi-Tek to help in bring back up the BHN (water quenching from oven) from annealing when baking of the coating to the boolits. The hard part about baking the coating too hot and/or too long to be able to quench, for example a wheel weight boolit in my case, is the coating becomes brittle and can flake off upon a smash test. I have more testing to do before I can put a definitive answer to things. And yes I could simply alloy a harder boolit however I do not want to make it brittle by using lino alloy.

[Zthomps]

Thanks for the texting saves me sometime

[Dragonheart]

Sense PC acts as a lube and seals to the barrel can you use pure lead sense the PC will make up for the lack of hardness

I hate to disagree, but I don't want to see those new to the subject given incorrect information about PC.

PC does make up for a lack of alloy hardness. I and others have tested as powder coated (.003" thickness build out from the substrate) pure lead and soft alloy at velocities greater than alloy pressure tables indicate possible, without damage to the bullet due to spin-up.

The retrieved bullets show no sign of tearing, just the normal grooves cut by the rifling. The polymer is completely bonded and the bullet base shows no indication of gas cutting at velocities over 3K, without a gas check, and no leading of the barrel!. The projectiles cut clean non-ragged holes in the targets indicating their stability.

The polymer is a lubricant, but it is also performing as a jacket. For someone to to offer a differing opinion I would like to see what actual testing they have done. At the present time a PHD Physicist friend is testing the effects of PC on soft alloy rifle bullets to determine the limits of the polymer.

Just ask yourself this, if polymer has no merits other than just a colorful lubricant as the detractors tout, then why are major ammunition manufacturers spending so much time and money in developing new technology in polymer bullets?

[OS OK]

Ummm, errr...because it's the way of the future? A new technology applied that works?

I'm anxious to see what they say about the BHN of the cores, I imagine that we are going to see a substantial lowering of the currently required BHN for conventional lubed rounds when encased in this poly-jacket.
Wasn't it in the 30's or thereabouts, that when they referred to a hard lead they were implying 12 BHN and using that same hardness for the magnum calibers?

[dahermit]

If you are relying on PC to compensate for low hardness and poor mixing of your alloy for rifle boolits....I feel sorry for you friend.

There you go with assumptions my friend.

[popper]

I use isocore alloy for my rifles (with a tad of Cu) PCd. 30/30, 300BO & 308W, all 1:10 twist. I'm finding that above ~ 40K psi I need to add some (1%) Sb to increase hardness or I get the 'white' smoke of PC failure. Accuracy doesn't go away suddenly working up the load ladder but it is evident. Don't know if it is PC , bond or alloy failure. Appears to be about the point I need GCs.

[rondog]

So, does the general concensus say that it's OK, perhaps even preferable, to take freshly PC'd boolits right out of the oven and dump them into water?

I'm fixin' to do a bunch today. I've previously just let them air cool, but if quenching is better I wanna know.

[dahermit]

actually we care more about consistency and C.O.R. balanced boolits at velocity more than BHN.
once y'all figure out how to apply a perfect .002 coat your gonna have a ton more interest.

Yah...as it was (past tense, some years ago), I was using a 190 grain (Wheel Weights + 2% Tin, heat treated), Saeco two-diameter, bore riding bullet (Powder Coat would have made the nose too big), so I doubt that I would have tried Powder Coating it...it fit really good just the way it was. Also, I was getting very good accuracy for a production gun (Ruger #1-B, in 30-06), less than one inch five shot groups. I was using indexing (had an index mark on the bullets), and as I remember, about 24 grains of Rx 7. The 30-06 was not an ideal cartridge (way too much space in the casing), and I looked for an alternative (a smaller cased, more efficient .30 cal.). I found a Ruger M77 Mk.II in 7.62x39, but I concluded that the barrel and gun were too lightweight to be a contender in the production class. I also came across a Winchester 54 in 30-30 and fooled around with it to see if it would make a production class gun, but I could never get it to shoot as well as the 30-06 and when I was well into the project, it occurred to me that because it did not have the original stock (I looked but could not find one), it could not be shot in the production class anyway...and I had no interest in trying to shoot it in unlimited. There were still some ideas for improving accuracy I wanted to try (like loading at the bench using only one indexed casing), with that 06 but began to lose interest in rifle shooting and shifted to more of a handgun shooter, which was where my interest lies anyway. In short, I do not see Powder Coating as yet matured in regard to Bench Rest Competition shooting of cast lead rifle bullets (but then I dropped out of the Cast Lead Bullet Association and have not read the Fouling Shot for some time now), but the technology is likely still evolving...after all the first airplanes in WWI were incredibly primitive (as all emerging technologies are), could hardly fly but evolved as the war went on.