Multiple coats really necessary? - Coated Bullets

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B y r o n
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Multiple coats really necessary? - Coated Bullets

Post by B y r o n » Sun Feb 03, 2019 3:15 pm

So I've been reviewing the bullet coating processes that are being used and also the products. One of the things I saw in the majority of the reviews/processes was that they were coating them 2 to 3 times on average. Most of the time it seemed to do with making the bullets look better. My question is; Is it really necessary to coat them more than once if your only concern is keeping the lead from making contact with the barrel or preventing lead dust from being deposited in your suppressor?

Also, how does the process of coating them affect water quenched bullets that you are trying to make harder?

For me casting is about economy as well as self sufficiency. Sure it takes longer to cast than buying already manufactured bullets but not having to bake the bullets 2 or 3 times means you can get to the range quicker.

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gds
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Re: Multiple coats really necessary? - Coated Bullets

Post by gds » Sun Feb 03, 2019 4:15 pm

I dry tumble. One coat. Dump them in a tray and bake them at 400 degrees F, for 15 minutes. Not 100% coverage but has served me well for thousands upon thousands of rounds.

I have found that if it takes more than one coat to get good coverage, then my powder is the problem. Keep it sealed in a good container when not in use than it should last a good amount of time.

When powder coating, in my opinion the hardness of the bullet is irrelevant. Member Dolomite Supafly has runs some soft lead powder coated at rifle speeds with no problem.
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Re: Multiple coats really necessary? - Coated Bullets

Post by TRshootem » Sun Feb 03, 2019 11:36 pm

ONE coat is fine, 2 coats will add a few thousandths thickness and may shorten your load OAL. This is especially true for pistol bullets. If you cast for BLK bullets, hard BHN cast will size with a good deal more effort. Softer mo betta :P

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Re: Multiple coats really necessary? - Coated Bullets

Post by GunFunZS » Thu Feb 07, 2019 6:53 pm

Multiple coats is a great way of stacking tolerances. Just say "no" to that nonsense.

Dry tumble. No BBs. No song and dance. With or without a vibe tumbler, if your powder is good, and you have no moisture or other contamination issues.

Don't waste a single second standing up bullets. That just wastes time and worsens the surface finish on the base of the bullet, which is the most critical area, as it passes the crown.

Instead:
1) Check your oven's temp against a thermometer. Preheat while you tumble. Follow the directions for the powder you are using.

2) tumble until the coating is thin and uniform on the bullets. If you are having issues, dry them at very low temp, and try again. Or in a vibe tumbler, tumble until they coat well, which is another way of just letting them dry until static builds.
3) Sift off excess powder, and pour the bullets onto a clean mesh rack tray. don't touch them. I keep a clean paint stirrer to spread them out so I don't contaminate them, and I minimise handling. I don't worry about bullets touching, but you don't want large flats in contact. If a couple happen, NBD. Just recast those. It's a better use of your time than fiddling about micromanaging your bullets and messing up their finish.
4) Pull them out of the oven HOT, even a little bit before the stated full cure time. Knock them into a very clean cardboard box, and bash them around. This will let the coating cool, but not allow any to stick to each other. Since the thermo set plastic coating is still hot enough to flow a little, surface tension will even out any minor marks from contact with other bullets or the rack. These will be far less of an issue than the crust ring on the base that comes from over working things and standing them all up.

5) serve with a toothpick, and tell your guests to guess what the flavor is.

6) if you want to size them, do it at this point. Sizing can work soften lead, so you may wish to put them all in the oven after sizing, at 400*f for 40 minutes and then throw the whole batch in water. This will uniform out your heat treat from bullet to bullet and you will be at full max hardness for your alloy. Much less variance than you get from water dropping out of the mold.

I know you've probably read a thousand different strong opinions about this, but that's my .02.

Do no action that lacks a measurable advantage. That cuts out BBs, standing up, naming each bullet and whispering encouragement to it, wearing your lucky socks both on your left foot, silicone mats, and possibly gas checks, though the data conflicts on that last point.

Double coatings are in this category too, since not only are they not providing a measurable advantage, they are necessarily increasing the variability round to round. If you think of the bullet as one component, the first layer as another component, and then the second layer as an other component, it is pretty obvious that each of those has a range of variability to it, and when those tolerances coincide in one spot, they add to eachother giving you maximal inconsistency. Fewer parts is fewer stacked tolerances.

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Re: Multiple coats really necessary? - Coated Bullets

Post by GunFunZS » Thu Feb 07, 2019 7:03 pm

TRshootem wrote:ONE coat is fine, 2 coats will add a few thousandths thickness and may shorten your load OAL. This is especially true for pistol bullets. If you cast for BLK bullets, hard BHN cast will size with a good deal more effort. Softer mo betta :P

p.s. you can make a flap hone by taking a piece of 1/4" rod and carefully taping a square of 2000 grit automotive paper to it. coat in light oil and rotate inside your sizer with a drill at low RPM. It should be a tight fit, but not so tight that the paper will tear. It's tricky to get the size right, so just make it oversized and trim off paper until it fits. You will feel heat and drag. It will leave a much better surface finish in your sizing die. A couple minutes of this won't make a change in the diameter of the die, but I have corrected sizing dies which were undersized using 1k grit to start, and about 15 minutes of honing, including frequent stops to check the results.

When you are done, you will find that the die sizes with much less force.

Do at your own risk, and remember that the worst that can happen is that you just made a larger sizing die in a non standard size, and you can get a new one for $25. People argue a lot about spring back, etc. I don't have the correct bore gauges to preciesly measure the I.d. of the sizer, but you don't care about that anyway. You care about the final dimension of an oversized bullet you pushed through. I used uncoated lead with light oil when checking, because I didn't want any squishiness of PC to throw off my measurements. After sizing a lot of PC bullets, I doubt it would have hurt to check with oversized PC bullets.

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Re: Multiple coats really necessary? - Coated Bullets

Post by popper » Thu Feb 07, 2019 10:09 pm

Two coating processes are PC and hitek. Hitek takes 2 coats and is applied as a liquid. PC is powder applied, shake & bake or electrostatic spraying. PC generally takes a single coat but 2 may be applied. Both require baking to set the crosslink process into action. PC is easier, with generally acceptable first try results. Hitek works fine, a little trickier to get results the firs time. Both work well for pistol or rifle.

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