simple Hi-Tek coating

[HI-TEK]

ThaDoubleJ
Just curious, the metal I see in your picture certainly does not look like 92. 6. 2 alloy.
What alloy are you using. The picture seems much too white for Lead. May be it is the light, but am not sure.

[ThaDoubleJ]

Those flakes in my picture are crispy, like corn flakes, you can pinch them and they make a noise and break. Is that normal?

It's the light, and poor focus. Those boolits are wheel weights with a splash of tin thrown in.

[HI-TEK]

Those flakes in my picture are crispy, like corn flakes, you can pinch them and they make a noise and break. Is that normal?
When resin is simply dried, it is crunchy, and will break as it is brittle. It is quite normal

It's the light, and poor focus. Those boolits are wheel weights with a splash of tin thrown in.

AH..HAAAA, you may have answered your own question why the coating may not bond to alloy.
Wheel weights are loaded with other contaminants, and many of those contaminants react with coating and prevent bonding.
You may have a three fold problem.
1. Alloy contamination
2. Not dried enough
3. Not enough heat to correctly cure/bond first coat.

[ThaDoubleJ]

That's troubling. Wheel weights are all I've got, all I've ever used. Any chance it's our crappy water? Tons of calcium in it, maybe it's closing up the pores of the lead when I quench?

[HI-TEK]

That's troubling. Wheel weights are all I've got, all I've ever used. Any chance it's our crappy water? Tons of calcium in it, maybe it's closing up the pores of the lead when I quench?

I suggest following.
Get some Hydrochloric Acid, (Muriatic Acid) as used for cleaning Concrete.
Mix about equal amounts of water with it in a plastic container, and soak some of your cast in this mixture.
USE CARE AND RUBBER GLOVES AND EYE PROTECTION IN CASE OF SPLASHES.
After about 10-15 minutes, carefully remove soaked alloy.
Keep acid mixture for re-use if this works.
You must wash and rinse well with running water and dry well. Heat to dry off water to 50C-60C, at least for about 1/2 hour.
Try and re-coat with first coat. Dry this first coat well again at about 50C for at least 1/2 hour.
Then test bake this first coat at 200C for 10 minutes.

My idea/intention is to try to remove any surface contaminants and leave an etch on the surface of alloy as a result as well.
This should significantly improve adhesion, if surface or alloy contaminations are the problem.
Again, do not multiple coat, always test if first coat is bonded before you attempt recoating.

[ThaDoubleJ]

Think I've got a bottle of that stuff somewhere, I'll give it a try. It'll be a while, it's like 11 degrees outside, but I'll check back in.

[benellinut]

I also dried the boolits ten minutes outside, and then warmed them up on the oven before actually baking them, as recommended.

Think I've got a bottle of that stuff somewhere, I'll give it a try. It'll be a while, it's like 11 degrees outside, but I'll check back in.

Are you saying your applying a coat, then taking them outside in the cold weather to dry, then back inside and warming them on the oven before baking? Couldn't chilling them like that then warming the alloy create moisture on the alloy and under the coating?

[HI-TEK]

Think I've got a bottle of that stuff somewhere, I'll give it a try. It'll be a while, it's like 11 degrees outside, but I'll check back in.

AH>>>HAAAA....... another clue. 11 degrees F is minus 12 degrees Celsius.
It is impossible to dry any thing in these conditions unless you use heat well above ambient conditions.
I suggest 45-50C or 110-120 DEGREES F. as an adequate drying condition under the circumstances.

When you coat, during when Acetone is drying, it can chill metal about 5 degrees below ambient.
This chilling effect, and your cold conditions, simply trap moisture inside coating.
The added coldness resulting with alloy chilling by solvent evaporation, the alloy plus coating attracts moisture.
This moisture is trapped within coating. Once a dry skin forms, what moisture that is caught/trapped in the so called dry film, can give you exactly the type of adhesion failures you have experienced.

When this moisture, is heated only to 100C (212F), it expands 1000 times its original volume as steam.. This "steam", that is produced, simply lifts coating off the alloy, and the heat in the oven sets the coating, but it is then not stuck/bonded to the alloy.

Aside from alloy contamination, and possible inadequate drying, I now tend to lean back towards your problems being caused inadequate drying with first coat.

Things are not that complicated. It is simply identifying step by step different things, one step at a time.
What you were doing is coating, coating, and coating, but had failures.
As said many times on this blog, make sure you coat first time, and get a good bond, which passes all tests, before coating again.

[wlkjr]

I live in the sunny south and my shop is climate controlled. I'd volunteer to coat some of yours with mine, but I'm going to be out of town for a month. If you don't get it straightened out within the next month send me a PM and I'll coat some of yours with mine and see how they turn out.

[Grmps]

That's troubling. Wheel weights are all I've got, all I've ever used. Any chance it's our crappy water? Tons of calcium in it, maybe it's closing up the pores of the lead when I quench?

DON'T QUENCH HiTek or PC, It's a waste of time (because you lose any hardness you gain when you bake the coating) AND it's an easy way to contaminate your boolits.

I drop my boolits on a clean towel. Store them in a clean closed container or ziplock's if I'm not coating immediately.
A fan really helps with drying. when 110% sure they are dry warm the tray of boolits on top of your oven for 10 - 20 mins until they are all warm to the touch (this ensures drying and gives you a jump on bake-curing)

1) Keep it clean
2) don't use too much "coating" (less tha 1 mil solution mixed immediately before measuring and applying)
3) don't swirl to long (10-20 seconds if the sound starts to change you've gone to long)
4) make 110% sure coating is dry then pre-warm
5) confirm oven temperature, bake until coating starts to turn dark (they are fine to shoot like this) then back off a couple minutes to confirm complete oven cure
6) test (smash and rub) between coats after boolits are cold BEFORE applying next coat.

[ThaDoubleJ]

It was probably in the low 30s when I started, all done outside. Coated them cold, warmed them on the oven until they felt warm and smelled bad after about ten minutes drying in the cold, then cooked them. Tried to recoat while still a little warm, but it didn't work out every time. I did forget to warm one batch (the third coat) but I was probably already busted at that point. I'll use some of these ideas next time it warms up a bit and see what happens, thanks all.

[Ausglock]

Before baking a tray of bullets, Put you hand on the bullets. Are they warm to the touch?
Yes?? good. Bake away.
No??? bloody well warm them up. A cheap fan heater is what I use in winter here in OZ.
A cold winter here is like 2deg C. about what??? 35 Deg F??

my benchtop convection oven needs 12 minutes at 200 deg C to correctly bake 2.5Kg of bullets.
Any less and they get wipe off. I use a K sensor inside the oven to read temp as any other thermometers are un-reliable.

[HI-TEK]

Before baking a tray of bullets, Put you hand on the bullets. Are they warm to the touch?
Yes?? good. Bake away.
No??? bloody well warm them up. A cheap fan heater is what I use in winter here in OZ.
A cold winter here is like 2deg C. about what??? 35 Deg F??

my benchtop convection oven needs 12 minutes at 200 deg C to correctly bake 2.5Kg of bullets.
Any less and they get wipe off. I use a K sensor inside the oven to read temp as any other thermometers are un-reliable.

From what I have learnt, (again at the very end) with these failures is, that after coating, the coated projectiles were put outside to dry.
Outside temp was from minus 2 to minus 12 Degree Celsius.
Nothing will dry at those conditions.
Any moisture absorbed will turn into ice even inside the coating.
I am totally bewildered with this one...... No wonder he is getting failures.

[Ausglock]

Yep. it isn't rocket science.
water freezes below Zero Deg C. so placing them outside in below Zero obviously will not allow the moisture to dry off.
Then, bringing them into a warm place will cause the ice to melt and become water again.
try and bake this and of course the coating will fail because the trapped moisture is STILL THERE!!!

[Avenger442]

We wish you a happy Jesus' Birthday! And a happy New Year!

For you guys that are having summer and it's 2AM, hope your Christmas is as good as it can be.

Thank you guys for your patience and putting up with us all.

Dennis

[ThaDoubleJ]

Sorry, but I can't attribute this round of failures to temperature. Last attempt it was probably 70 or 80 degrees out, same results. I know it's a 468 page thread, and it's not your job to remember every post, but I've been here 5 or 6 times with failures of one sort or another, and I've never failed the smash test prior to this. I've made the most horrible looking boolits with coating that looked like the surface of the moon and was unevenly 4-8 thousandths thick, and they still passed both the smash and the wipe. The more I think about it, the more I think it's the water quenching that's the problem, it's the only thing I've changed. The water in my town is so bad I won't even let my cat drink it. My guess is that when the boolit hits the water at 500+ degrees, it's somehow coating itself in calcium or some other gunk that's in there, which is making the coating stick to that instead of the lead, or who knows. Like I said, I'm just guessing. Hillbillies on youtube do this, it can't be this hard. Either way, it's 13 degrees right this second, and snowy, so on my next go round once we have a nice day I'll try again and go back do dropping them on something other than water and I'll report back. Just for the record, MEK freezes at -87 degrees C, or negative 125 degrees US, so even at 20 degrees or so here, it'd still dry eventually.

[Grmps]

DON'T QUENCH HiTek or PC, It's a waste of time (because you lose any hardness you gain when you bake the coating) AND it's an easy way to contaminate your boolits.

I drop my boolits on a clean towel. Store them in a clean closed container or ziplock's if I'm not coating immediately.

[Spaceball]

Hi.

Not sure if it has been asked but how long can I leave a power / acetone mix made up before it goes bad?

Thanks

[Ausglock]

The mix will keep for at least 6 months if stored in a cool dark place.

[Grmps]

If the mix has evaporated a bit you can add acetone to re-rejuvenate it.
If I'm not mistaken, it can be used for a longer period of time but the color will deteriorate.
Joe or Trevor can confirm that.