How do you do multiple coats?

[Stilly]

Pretty straight forward question.

I have noticed that on some of the powders that do NOT coat well in one shot, it works very well to either combine them with another color that DOES do well, or use them as a top or base coat in a two coat process.

BUT. I have always heard of HALF CURE and that got me thinking, is that just half the time?

Is there a certain point that the PC should look like? Maybe feel like as well?

I THOUGHT I did pretty good with some half cure base coats, and then afterwards I just did a full burn and let it cook for the 10 minute cure time @ 400, but I noticed I THINK that maybe sometimes if I half cure too long, it makes things a bit slick and they do not want to play well, so the second coat will contract and stick to itself and then bead up and fall off, or just get really small spots in some instances. Like when you write on wax paper with a water saturated paintbrush.

So do I eyeball the PC oven and just let it go like it has been doing?

OR, do I hook up a PID to the toaster over, tell it to go full burn and crank the timer all the way over and set up a digital timer and do exactly 5 minutes at 400 deg?

Has anyone really played around with that much?

I was hoping the half cured pills I pop out would not be as slick as they are, but as it turns out, they are a bit slicker than I think they should be.

OR do you just do two full cures and say hell with it?

:\

[Beagle333]

Two full cures. I do the second coat just like I had never done the first one. 8-)

[Maximumbob54]

Just posted this pic but for the sake of the thread:

http://i1176.photobucket.com/albums/x333/Maximumbob54/Reloading%20and%20Casting/20150915_202742_zps0pjm9q4i.jpg (http://s1176.photobucket.com/user/Maximumbob54/media/Reloading%20and%20Casting/20150915_202742_zps0pjm9q4i.jpg.html)

This is the second coat after baking. I like just dumping them on the hardware cloth and if it's too thick then they stick to each other and too much to the grid. If I do two thin coatings then they hardly stick to anything. It takes twice as long but it's easier. I've dragged it out to three coatings and it did work well but seemed too unnecessary when two does just fine. If I do them in one then I have to poke them around to be sure none are touching each other and they are glued to the mesh and leave lines in the coating. I don't mean that as just an ugly visual, I'm worried if they are around the base or the bearing surface it might ruin them. So two thin coats eliminated this issue enough. And I never short the bake time.

[bangerjim]

If all is with you (tub, powder, humidity, method, tide cycle, phase of the moon) you should need only one coat. In helping to develop this and doing it for over 2 years, I have never had a batch need more than one coat.

If you feel you do need 2, bake fully each time.

Look closely (magnification) at the ones you think are not coated. You will see there is clear "plastic" over those lead-looking spots most of the time. The pigment did not fill-in but the resin (epoxy or polyester) is there.

Do what you need to, but if you, I would figure out what in the process is preventing perfect coats with only ONE swirl/shake/bake. (You ARE shaking HARD up and down for 10-12 seconds, right?)

Most commercial powders come with the spec of 400F for 10 min. That 10 min is AFTER the powder turns shiny in the oven. Cooking for 20+ minutes at 400F does not harm the coating, just wastes your time and electricity.

Putting a controller on an oven is a waste of time in my book, but some swear by it. Does nothing more than monitor a single temp at a single point in the oven cavity. Just use a good convection oven, check the dial temp with a good oven thermometer, and mark 400 on the front if it is off.

Keep at it. You WILL get there. I can do this with my eyes closed and get perfect coats (for BBDT) every time.

Remember, the more coats you put on the thicker the stuff gets and the more it will tend to make the boolit lop-sided in weight and bore travel and impact potential accuracy. One coat of 0.002" is enough for me and my guns.

banger

[Stilly]

This is my method, I started doing it before I was aware of the updated methods of using number 5 and .25g AS bbs...

I first started with the lacquer thinner and it was cool, but messy. I did that for about 2 batches then stopped.

I then moved to getting some square number 1 or number 3 containers (I forgot what they are made of) and I would put in some powder and boolits and then put the container into my thumler surrounded by rags (suspension) and let it tumble for about 20 minutes. THAT gave me great results but I realized that the longer I tumbled the darker things got. So I could tumble for about 6 minutes to about 25 minutes and have varying shades of boolits. I accidently left the thumler on overnight and 26 hours later stopped it and was disgusted at the gnarly mess inside. Me being cheap decided to toss the container, get a new one and I ended up coating them all for about 2 more times before they were usable to me. God they were NASTY looking blackish green and they had started as a flourescent green...

This accident prompted me to come back here and read some more and then I saw the bbs, so I purchased about 7 more containers to tumble in, about 30k+ bbs and I have been VERY happy letting things tumble for a while with a very even shade of color across the board. I can tumble for about 15 minutes, MAYBE even less, well, I KNOW I can tumble for less, but the norm is around 10-15 minutes it will tumble while I am doing other things (sorting them, sizing, pulling others out of the tumbler) I am just now getting my number 5 container collection up and ready to go to see if it is any easier, but I have been letting my thumler do all of the work for me until this point.

SOME colors do NOT spread that pigment around as much as others do. I have a blue and a white and some of my more exotic colrs seem to do great, but not all of them are that good. I find that worst case scenario I have to coat TWICE, but I do not like putting the powder on top of a fully cured coat. There MUST be a reason why the professionals that sell PC tell you to do HALF cures for the base coats in their two coat systems. But since I tend to operate on a different page then everyone else, I figured that maybe I have been doing something wrong and last night I decided to see if I need to correct what I am doing any or if I can get a little more precise. I DO need to check the temp of the oven though. Maybe today I will get my oven thermoneter in it and see what it goes to.

Yes Jim, I am aware of the plastic coating and that has made me feel better about some of the boolits I have coated, but those people that are not like us, they do not see those things as clearly as us so they think things are not coated and they complain about them so I just try to coat and make them look as beautiful as I can. I want first rate things coming out of my PC oven and there are several powders that are NOT first rate as a single coat. I have that HF white and it mixes in with other colors to make AWESOME blends, or off white with a hint of other colors that are mixed with it. It is AWESOME to see the pills come out looking like granite. But HF white by itself is too white and shows spotty coverage. Blended with tiger drylac BLUE or emerald green gives very NICE results with mostly one coat from what I have seen so far.

I think that if I was closer to doing a proper half cure that the second coat might interlock more and give a better bond.

I also noticed that the other night, I put a pill into the vice and smashed it flat on half, then whacked it with a 2lb hammer and when it came out, I noticed that the PC was slightly absent in the vice area and I could see exposed lead where before it was not like that.

Maybe I did not let it cure enough or let it sit long enough after baking?

I am going to revisit this and hammer/vice another one today. Maybe I will need to let it cure longer.

[bangerjim]

My hammer test:

Set baked boolit base down on my 4" x 2" thick steel round
Pound it to about 1/2" thick with 3# hammer
Lay on side
Pound again
Lay on other side
Pound into a final square of lead.

NO...ZERO...NADA....ZIP PC ever flakes off. PC can and will crack due to lead expansion, but it should never flake. It will always be tight to the Pb surfaces.

Now, THAT..................is a hammer test! :coffee:

If your boolits will survive that, you are doing something right somewhere.

bangerjim

[Stilly]

Yeah, I have some prior PC that I smashed in the vice and then with a hammer and NOTHING came off, you can even see the gridlines in the vice smashed stuff, but the other day I did this to some .44 mag that I made the other night, last weekend actually, I baked some 44 mag and smashed them in the vice and hammered them on top and when I opened the vice I noticed that the only place where there was exposed lead was where the vice smashed it. I was in awe...

[mongoose33]

I think there's a difference in whacking a PC'd boolit with a 3# hammer and crushing it in a vise. Most vises I've seen have a textured surface between the jaws; in essence that cuts into the boolit, and stretches and pushes the PC beyond what it can handle. As long as wherever the boolit has bulged after crushing in a vise still holds the PC, I think that's ok; where the jaws push into the boolit, I don't see it as unlike the striations engraved in a PC'd boolit if you slug the barrel with it.

[popper]

I've second coated ESPN after the first coat got scrape marks from the sizer. It seams to happen on harder alloy. No problems, it was ~36bhn and accuracy was as good at 100.

[Stilly]

My previous vice smashed pills and showed no marks of metal. I will smash some more and see tonight maybe.

My previous attempt to show someone how tough PC is, I cast some 44 mag about 4 days prior, then I PCed it, then after about 25 minutes from being out of the oven I sized it and then about 15 minutes later I took a pill over to the vise and cranked it in there. It smashed it pretty good. Then I pounded on it with a hammer. When I undid the vice the boolit had a LOT of bare metal. But I did not see any PC that had chipped or flaked off, I just saw the bare metal. MAybe I squeezed it harder this time then before. I do nto know. Maybe I did not wait long enough after cooling to perform this?

Jim, have you taken a pill out and given it the hammer test within an hour of it being out of the oven and sized?

Is there a hardening stage after they come out of the oven that you gotta let them sit before smashing them?