Hi-tek powder shelf life?

[mark2215]

I am going crazy trying to figure out why my hi-tek isn't working.

I used this same exact hi-tek powder purchased December 2017 for thousands of bullets last winter without any problems.

Here's my process:

-My oven temp is 390-400F pid controlled.
-I mixed up a new batch (actually 3 different times) using 10 grams of powder and 50ml of acetone.
-I use 1/4tsp (1.25ml) of mixture for 2 pounds of bullets for first round, 1/2tsp(2.5ml) for second round.
-I swirl in a bucket until almost dry but stop before all the acetone is evaporated, the bucket is still a bit wet.
-I dump the bullets onto a wire basket and place on a fan for 12 minutes to dry.
-I put in the oven and bake for 12 minutes. I tried 10 minutes and 15 minutes, no difference.

After baking I let the bullets cool and the coating wipes right off with acetone and a paper towel.

I tried diluting the mixture 10ml at a time until I got to 120ml of acetone in 10 grams powder, no luck.

I tried bullets from a different batch in case I had contaminated lead, no luck.

I tried letting the coating dry for over an hour before first baking, still no luck.

I'm thinking the powder is no good. I tried 3 different containers/colors of hi-tek and all three have the same exact problem. The powder is just over a year old, was stored in a cool, dry place for the past year. The powder looks fine, not lumpy at all.

Any suggestions on what else I could possibly try before I give up on hi-tek? I spent too much money on various colors to color code my various sizes. If the powder goes bad before I can barely make a dent in to container it's not worth it.

 

[pastera]

Have you tried a new container of acetone?
I would try a new container of acetone to mix up a batch in a new bottle and use a new container to tumble (get rid of any chance of contamination)

I was having issues but it was not too little acetone and not enough drying (for MY processing) - now I mix thin (20g/150ml), tumble in a closed container for 15 seconds, open tumble a short time and then dry for 12 minutes.
Also use 1ml/lb and three coats.

Reading over at cast bullets - the coating needs to reach 380°F for at least 2 minutes to cure. If you are processing too large of a batch they may not be hitting cure temperature, especially this time of year. I use 12 minutes for 2 pounds and 15 for three in a very small toaster oven.

Calling the expert: @Michael J. Spangler

 

[mark2215]

I used two different containers of acetone. I ran out of a small bottle I had so went and bought a new gallon can of acetone. I tried 3 different bottles (new) to mix the different batches. I used new buckets for each batch for swirling (automotive paint mixing buckets).

I really don't believe it's my process as it's well within all the guidelines I've read everywhere online and it's the same process I used last year with no problem.

Right now the only way I see to verify my suspicion that the hi-tek powder is at fault will be to order some new powder.

 

[38ExtraSpecial]

I would try to bake longer.
If the bullets aren’t getting super dark then you’re not running into an issue with over baking.
So bump up the time and take out a bullet every minute to test. Take the whole batch out once you find one that passes the test
Sounds to me like a temperature or time issue.
Do you have some pictures? They might help to evaluate the situation

 

[pastera]

Do you still have some mixed? Might take longer to activate. I've never mixed then used - it's always mixed many days before use (simply timing not on purpose)

Also, try a small batch and let it bake a little longer

 

[mark2215]

The mixture I had mixed from last winter was dried out and I tossed it. I do have some left from today's trials that I can try again tomorrow.

I have been doing 2 pounds at a time which is small for what I used to do.

I tried 15 minutes for baking, guess I'll try longer. I can also increase the temp but everything I read said don't go much above 400 which is right where I'm at.

I'll take some pictures tomorrow. As far as appearance the thing I noticed was even with the very thin mixture (over 100ml acetone to 10grams hi-tek) the bullets looked spotty where as I remember last year when the mixture was very thin it would just be a very faint even coating over the entire surface.

Send me your addresses and I'll send you some powder. You can help me troubleshoot.

 

[38ExtraSpecial]

Take pictures before and after baking with each coat.

 

[mark2215]

Quick question, do you get zero color wiping off when you test after coating. I tried turning the heat up a bit and had better luck but still get a bit of color if I really rub the bullets with acetone. I took a few pictures of my trials. There was a noticeable difference between 12 and 14 minutes, after that time doesn't seem to make a difference. These are after one coat, baked from 10-30 minutes. Should I try turning the heat up even higher, running around 410 right now.

 

[pastera]

You have a PID control - can you drill out a bullet, insert the thermocouple and drop that into the bullets to measure the time it takes to the bullets up to temp?

 

[38ExtraSpecial]

I wouldn’t call that an issues. If it’s not cured it will look just like the un baked one.
Any chance you are getting some in your fingers or you have dirty gloves while doing the wipe test? I’ve had that happen and the bullets were fine but coating stuck to my gloves was making a mess of the towel

 

[mark2215]

Nope, I used a rubber glove and changed them after each wipe. I think I'll try to bump up the temp a bit more. Do you know what would happen if they were baked too hot?

 

[pastera]

Baked too hot or long gets darker
Way too hot will slump or melt

 

[38ExtraSpecial]

If they’re too hot the get dark.
I’ve had some in the bottom of my oven for over a year.
They were fine. I didn’t load them but I’m guessing they would have shot fine.