simple Hi-Tek coating

[Stephen Cohen]

I'd like to report something interesting:

I cast a bunch of 615 grain 50 cal bullets and was kinda hurrying up to get them done. So I didn't weigh them but did the math in my head... wrong.

I used 8 ml of coating for 5 lbs of bullets,three times. I noticed they were swimming... but I went on,coatings were good looking... I found out the real weight the day after. My coating was a mix again, 2 ml Tru Blu, 6ml TMG Gold Original. I like these greens I'm getting.

The thing is,smash and wipe and scratch and bite and whatever test I do, this coating has bonded perfectly and is just thicker than usual. Approx. 002". Looks good,elastic,glossy,as you can see. Tough coating.



I sized and loaded some today, 1100 fps, almost 50 k psi, working fine and clean.



My first coat was absolutely too thick. No problems whatsoever with this mistake.

Petander. They look great.

[RydForLyf]

Don't go softer alloy!!!! 9mm loves hard alloy...soft will lead worse..
2,6,92 alloy is 15 to 16 BHN. all our 9mm bullets are made with it.

Roger that. I’ll look for some known alloy to try. Thanks.

[slide]

RydForLyf, I'm sure you are aware of rotometals. You can buy some known alloy there.

[Papercidal]

RydForLyf, I'm sure you are aware of rotometals. You can buy some known alloy there.

Look at Missouri bullet they sell hardball alloy at a price that it’s almost not worth messing with scrap metal (under2.50a pound) and when I had leading issues I got some to eliminate the mystery alloy I was using from the equation (the coating was already proven).

[Petander]

I melted and fluxed a 50 lbs "pure lead" bar.

Not much to flux,alloy looked good. I cast some chrome shiny RB:s while coating other boolits, then put RB:s in Acid Test... "BAM!".



It really is a good practise to test all alloys before coating,no matter how " pure" someone tells you. This coating would have failed in a mysterious,unpredictable way.

Now I just clean them up,add a drop of Hydroden Peroxide to speed up the impurity cleaning. Rinse. Done. Will coat great.

[RydForLyf]

RydForLyf, I'm sure you are aware of rotometals. You can buy some known alloy there.

Yes I am, but they're a long way away from Georgia. I need to see if I can find someone closer to me.

[RydForLyf]

Look at Missouri bullet they sell hardball alloy at a price that it’s almost not worth messing with scrap metal (under2.50a pound) and when I had leading issues I got some to eliminate the mystery alloy I was using from the equation (the coating was already proven).

Thanks, I will give that a try.

[RydForLyf]

I melted and fluxed a 50 lbs "pure lead" bar.

Not much to flux,alloy looked good. I cast some chrome shiny RB:s while coating other boolits, then put RB:s in Acid Test... "BAM!".



It really is a good practise to test all alloys before coating,no matter how " pure" someone tells you. This coating would have failed in a mysterious,unpredictable way.

Now I just clean them up,add a drop of Hydroden Peroxide to speed up the impurity cleaning. Rinse. Done. Will coat great.

This is one thing I'm not sure on. My 80% COWW 20% Lino pours shiny, not frosty. I keep my casting pot @660F and cool the mold off on a damp towel instead of timing. I haven't tested mold temp with IR, but may do that.

Regardless of temps and appearance, I can smash the heck out of my HI-TEK coated bullets and it works great. Nothing has ever flaked off or split or done anything other than deform to the new shape. Even though the smash test passed, is there a chance I have a bonding issue? Maybe I need to recover some to see how much coating is left.

[Petander]

Regardless of temps and appearance, I can smash the heck out of my HI-TEK coated bullets and it works great. Nothing has ever flaked off or split or done anything other than deform to the new shape.

You're doing good.

I got Niobium contaminant in my alloy,the contaminant came from Monotype. My WW is clean but I mixed a ton with that mono 15 years ago... very little pure WW left.

Anyway my start with Hi Tek was strange and frustrating (especially to others) until I got my alloy analyzed. Now I just clean it all,everything I cast. Working great.

[RydForLyf]

Did a bunch more testing today and my TruBlu turns green when internal bullet temp hits 340F (171C). I am using 3 different thermocouples. 1 is inserted into a bullet in the middle of the tray. Another is measuring air temp under the tray and the last is measuring air temp above the tray, measuring any radiant heating the bullets would receive. You can see the probed bullet and also thr light brown wire from the other thermocouple in the pictures below.

I tried several times to do 4 bullets with the probed bullet in the middle. Even when oven temp was maintained about 340F (171C) and internal bullet temp was 330F (165.6C) to 335F (168.3C), after about 1 minute, it turned green. Total time between 330 and 335 was 3 minutes. End result is a green bullet that fails the wipe test as expected.

One thing I will do next is to add about 20 pounds of lead ingots to the lower rack to give some thermal mass and more temperature stability. Right now, temperature drops a good bit when the door is opened because there’s just no thermal mass, only hot air. Then the element comes on to replace the lost heat and the bullets are hit with all of the radiant heat.

I’m not sure what else to try and am open to suggestions. Thankfully, it is a green my wife loves.

Starting point.


Blue at 325F internal bullet temp.


Green at 343F internal bullet temp.


Greener at 345F internal bullet temp.


Final product.


The 125 grain bullets were on second coat. The 175 gn TC bullets were first coat.

Here is how I was cooking the 4 individual bullets, with probed bullet in the middle.


Here is what went in and what came out. Note that I never got internal bullet temp to 180C (356F).

[Stephen Cohen]

RydForLyf , It will be a few days before my back yard is dry enough to try the Blue Hi-Tek, So I have not tried it as yet. I note the cast with the probe in it is uncoated, I wonder if this will give you a proper temp reading of what the coated cast are reaching. I have had problems with colour change with other colours in the past and I found drying over night cured it, I don't know why this was and frankly don't care because I cast and coat in the same day and bake the next. Just a thought that may help. Your wife is right it is a nice green. Regards Stephen

[ioon44]

RydForLyf,
If your element is below the lower rack then there is a good chance the 20 lbs of lead will melt.
I added a layer of fire bricks on my lower rack to cover the lower element but if I drop a bullet and it is by the lower element the bullet will melt.

[Petander]

My "radiant heat" is not directly from the elements. They are covered. It's the fan you can see in the back, it has a circular heating element going on/off and when "on" it blows hot,it really is hot. There's a cylindrical cold blower,too.

This is a true convection oven... Anyway,I have learnt to live with this for now. I know my bullet surface temps. I will build a more basic oven with a PID one day.

Mod. TMG Gold with 10% of Candy Apple:

[Avenger442]

RydForLyf
Sounds like if we could hit 180C in three to four minutes hold it for two minutes and immediately remove they would be blue. And according to Joe 180C bullet temp for two minutes they should pass wipe test. What do you think?

[RydForLyf]

RydForLyf , It will be a few days before my back yard is dry enough to try the Blue Hi-Tek, So I have not tried it as yet. I note the cast with the probe in it is uncoated, I wonder if this will give you a proper temp reading of what the coated cast are reaching. I have had problems with colour change with other colours in the past and I found drying over night cured it, I don't know why this was and frankly don't care because I cast and coat in the same day and bake the next. Just a thought that may help. Your wife is right it is a nice green. Regards Stephen

Stephen, yes, the uncoated bullet will be different. It will respond to temperature faster meaning my coated bullets are cooler than what I am measuring. I don’t think it really makes any difference because I’m watching a blue bullet turn green with internal bullet temperature just under 300 F. This is with oven temp about 365 F (186 C). By the time I get the bullet internal temp to 356 F (180 C) my bullets are already green.

[RydForLyf]

RydForLyf,
If your element is below the lower rack then there is a good chance the 20 lbs of lead will melt.
I added a layer of fire bricks on my lower rack to cover the lower element but if I drop a bullet and it is by the lower element the bullet will melt.

I added 25 pounds of lead today and the oven temps are more stable, bullets are still turning green with internal bullet temp about 300 F, way below “must hit” 356 F.

[RydForLyf]

My "radiant heat" is not directly from the elements. They are covered. It's the fan you can see in the back, it has a circular heating element going on/off and when "on" it blows hot,it really is hot. There's a cylindrical cold blower,too.

This is a true convection oven... Anyway,I have learnt to live with this for now. I know my bullet surface temps. I will build a more basic oven with a PID one day.

Mod. TMG Gold with 10% of Candy Apple:

Yeah, and maybe some new baskets. Your bullets are awesome, but your basket making skills, not so much.

[RydForLyf]

RydForLyf
Sounds like if we could hit 180C in three to four minutes hold it for two minutes and immediately remove they would be blue. And according to Joe 180C bullet temp for two minutes they should pass wipe test. What do you think?

I will try it. If that works, then the problem is time, NOT temp. I was cooking today with oven at 350 and started times when internal bullet temp hit 340. I let them cook for 3 minutes and they failed the wipe test as expected.

[RydForLyf]

I will try it. If that works, then the problem is time, NOT temp. I was cooking today with oven at 350 and started times when internal bullet temp hit 340. I let them cook for 3 minutes and they failed the wipe test as expected.

Tried it, but failed.

Two batches one at 200C (392 F) and another at 400 F. Both batches turned green around 300 degrees. Totally green by target temp of 180 C. I think something is wrong with this one batch. It’s just too far off to be missing something.

Any other ideas? I’ll try anything. ”

[Ausglock]

Hmmmm... ok... Talk me through your coating mixing process.

You should start with the powder.
20grams of powder to 100Mls of Acetone. It MUST be ACETONE. not thinners or any other rubbish you have lying around.
UN1090 Acetone or MEK...nothing else!!!!!
add a bullet to the mix as a rattler.

Shake like crazy..
let sit for 30 minutes to "react"
Shake like crazy and immediately suck up 6mls of the coating and squirt onto the 2.5kg of bullets to be coated.
swirl around until the bullets are coated for like 15 seconds.
Set aside to "dry"....NOTE : Dry does not mean "to the touch" Dry means all solvent has evaporated.
This is why I pre-warm my trays of bullets before baking....to make sure that the bullets are "Dry".

And then bake..
Does this look EXACTLY like your process?????????