First HT Boolits - Results and Questions

[Taterhead]

I've been using PC for 3 years now, but have been curious about HT. I suspect that at a certain volume, it might be a quicker overall process than PC. We shall see!

I did a sample of my "C" grade keepers.

Read the stickies and searched threads but here is a concern. The bullets are absolutely passing the smash test, but are failing the transfer test (rubbing on an acetone-soaked rag for 30 seconds). In each test, a little color shows up on the rag. I have not been able to resolve the transfer test.

I revisited the directions carefully.

More acetone is better than less. Check. Tried adding a bit more to the mix than the recipe called for.

Thin amount of coating. Check. Barely any on there.

Oven temp. Check. Pre-heated and verified by an oven thermometer. 9 minutes bake time.

Instructions said that too low a temp could be a culprit. So I tried one batch a little over 400 in case my thermometer was a little off. Turned almost brown. That tells me that it had enough heat. Same result with the transfer test.

Letting them completely dry before baking. Check. Definitely dry. Not at all tacky.

Here is one lot of 401638s with 3 coats of HT powdered Brick Red.

Not sure where to go next. One thing that occurred to me is that the powder has been sitting on a high shelf in my garage for 3 years where temps have been hugely variable (sub freezing to over 100f). Does it deteriorate? It is likely user error, however, but curious about storage concerns.

[Ausglock]

G'day... Just because they are NOT TACKY, doesn't mean they are "DRY"

Just warm them before baking. I use a fan heater to blow warm air ofer the tray of bullets. They are warm to the touch before entering the oven.
Slight wipeoff is NOT a fail. Some colours have a higher loading of pigment than others. A little colour on the white paper towel is OK.
Load them and shoot them... BTW...3 coats is overkill. The "Lube Groove" on the bullets pictured have far too much coating in them..

[Taterhead]

G'day... Just because they are NOT TACKY, doesn't mean they are "DRY"

Just warm them before baking. I use a fan heater to blow warm air ofer the tray of bullets. They are warm to the touch before entering the oven.
Slight wipeoff is NOT a fail. Some colours have a higher loading of pigment than others. A little colour on the white paper towel is OK.
Load them and shoot them... BTW...3 coats is overkill. The "Lube Groove" on the bullets pictured have far too much coating in them..

Hey, thanks for the note. That is reassuring to know that I might not have a failure after all. The instructions from Bayou Bullets said that no color should transfer.

Coupla clarifying points. Since these were test cases, they received 3 coats because the instructions said something to the effect of, "if this test fails, go back and repeat." It did look like ample coverage after 2 coats.

Pretty sure they were dry. I swirled and then dumped the bullets on a rack topped with mesh on top of the oven. There was some good heat. A box fan behind that pulling air over. They felt very dry to the touch and sat for another 10 minutes beyond that. Quite warm.

I'm going to keep working with it, but my initial experience tells me that I might prefer this method for my high volume stuff to PC.

[popper]

Try hammer smash test (smash real flat) and look for fine particles of HT = fail. That is way too much coating. Joe also indicated the powder may settle during shipping and to shake before using - it is a mixture of hardner and coating. IIRC, Avenger is only person to get it to work good in HV rifle.

[Taterhead]

Try hammer smash test (smash real flat) and look for fine particles of HT = fail.

Agreed. From my OP:

Bullets are absolutely passing the smash test

That is way too much coating.

Agreed, per the explanation in post #3 above.

Joe also indicated the powder may settle during shipping and to shake before using - it is a mixture of hardner and coating. ...

This is very good advice. Thank you.

[popper]

Look for real fine specks when 'massaging' them with paper towel, after smash. HT is more brittle than PC, may look like it sticks OK but may crumble when shot.

[Taterhead]

Look for real fine specks when 'massaging' them with paper towel, after smash. HT is more brittle than PC, may look like it sticks OK but may crumble when shot.

That's great advice. I'll take the few sacrificial smashed bullets and give closer inspection with a paper towel. They did look great, but will add the paper towel method.

I had some store bought Acme HT bullets that had brittle coating as you described. Could flake it with a fingernail. Really bad bubbly surface. Put in the oven wet?

[Ausglock]

Put in the oven wet?

Yes. baked too soon after coating.

[Taterhead]

Second attempt. 2 coats. Focused on going really thin on the coating. Color is blotchy and a little browned. This batch cooked at closer to 400F. 9 minutes. The first was more like 385 for 9 minutes. Very little color transfer on the 30 second acetone rub test. Smash test is fine too.

They are a little ugly but my guess is that they'll shoot ok.

Also, I've been resting the tray on top of the oven to dry. It might me a little too warm as evident by a few spots that bubbled up that were closest to the oven. Those will be culled. I will fashion a prop in front of the box fan to dry next time.

This is clearly one of those efforts that will reward precise repetition. I can see this being a great way to do a lot of bullets when rotating through a few different trays at each phase.

[Ausglock]

they look far better...shoot some.

[HI-TEK]

I've been using PC for 3 years now, but have been curious about HT. I suspect that at a certain volume, it might be a quicker overall process than PC. We shall see!

I did a sample of my "C" grade keepers.

Read the stickies and searched threads but here is a concern. The bullets are absolutely passing the smash test, but are failing the transfer test (rubbing on an acetone-soaked rag for 30 seconds). In each test, a little color shows up on the rag. I have not been able to resolve the transfer test.Colour removal after adequate bake is mainly caused by wiping off little blisters caused by inadequate drying. What happens, is trapped moisture, when heated expands at 100C about 1000 times its own volume. This causes tiny blisters which are brittle after baking. The blister "bubbles" simply rub off even if you don't use solvent, by the abrasion of rubbing. In majority these shoot OK< but don't look so great with being shiny and smooth.

I revisited the directions carefully.

More acetone is better than less. Check. Tried adding a bit more to the mix than the recipe called for.

Thin amount of coating. Check. Barely any on there.

Oven temp. Check. Pre-heated and verified by an oven thermometer. 9 minutes bake time. Depending on oven type, and adequate air circulation, may be 9 minutes may not be enough. You really need to concentrate on temperature of the load instead of oven temperatures. The load must get to 180C and stay there or above for about 2-3 more minutes to adequately cured. Oven temperature really does not tell user where his load is at any time with temperatures.

Instructions said that too low a temp could be a culprit. So I tried one batch a little over 400 in case my thermometer was a little off. Turned almost brown. That tells me that it had enough heat. Same result with the transfer test.
This is telling me, that you had adequate if not too much heat for time spent inside oven. Please refer back to what I said about load temperatures.

Letting them completely dry before baking. Check. Definitely dry. Not at all tacky. This area is a difficult one. Products may "feel" dry, but in fact moisture is trapped below a dry skin of coating. When heated, the moisture will form bubbles which are set in the coating film, after baking

Here is one lot of 401638s with 3 coats of HT powdered Brick Red.

Not sure where to go next. One thing that occurred to me is that the powder has been sitting on a high shelf in my garage for 3 years where temps have been hugely variable (sub freezing to over 100f). Does it deteriorate? It is likely user error, however, but curious about storage concerns. Unless product is in direct sunlight, it should be OK, but may have absorbed moisture with storage. This moisture must be dried out afte coating.

TATERHEAD
I have supplied some details that may be of use to sort things out above in RED
It is hoped that it helps

[Taterhead]

TATERHEAD
I have supplied some details that may be of use to sort things out above in RED
It is hoped that it helps

That is extremely helpful and taps into that part of my brain that does best when I understand what is happening. Thank you. I REALLY appreciate you taking the time to craft such a thoughtful reply.

After considering batch processing options, and being more appropriately schooled in the need for being dry, I think I may do this over a couple days. Coat several trays and let them dry overnight in front of a box fan. Bake the next day. This time of year it is warm and dry in the garage.

Then allow to cool and re-coat. Overnight dry again. Bake again the 3rd day. Cool. Size and done.

I can see being able to do a lot of bullets this way by spending just a little time each evening.

[Petander]

Just warm them before baking. I use a fan heater to blow warm air over the tray of bullets. They are warm to the touch before entering the oven.

I dry and warm my boolits the same way,every time. Sometimes they might wait overnight in room temp but I still preheat them before baking ~30 min so they are always the same ~50°C when they go in the baking oven. They are 50°C for about15 minutes.

Easy to get consistent results bake after bake in my climate, going from arctic to jungle.

[Ausglock]

Once they are removed from the oven to cool. place them in front of a fan to speed up cooling. 10 minutes later, apply the second coat.

[Sig556r]

9 mins total bake time seems too short, polymer-based recommends 10mins after flow, epoxy-based even longer...better to err on longer than half-baked

[HI-TEK]

9 mins total bake time seems too short, polymer-based recommends 10mins after flow, epoxy-based even longer...better to err on longer than half-baked

Sig556r

It is not good to compare Hi-Tek with other heat cured coatings. Hi-Tek requires only basic requirement when being heat cured.
The dried coating film/s and cast, must get to 180C, and stay there for another 2-3 minutes to adequately set.

Time in oven, to get a specific load to 180C, greatly depends on the quality of the oven system. I am aware of product baked in about 7.5 minutes.
That oven had twin high speed fans, and PID controlled heating elements and well insulated to prevent heat losses..

The oven is simply a controlled area where heat is generated, and the heat generated, must then be transferred from hot air into the load. Air is a poor conductor of heat, and heat transfer to load requires a cyclone inside oven to have hot air make contact with load being baked as many times as possible. That is the way even baking is achieved, and, fastest throughput and minimum bake time.

[Ausglock]

I can bake 2 trays (2.5Kg on each) at once in 7 1/2 minutes in my modified wall oven.
3 trays of the same weight takes 10 minutes, but top tray displays slight colour change due to being too close to the top heating element.

[Taterhead]

Man, this Hi-Tek stuff is making me brush up on the metric to imperial conversions. At least we still all mostly agree on grains! That I understand.

I like the concept of taking good measurements. Like baking, should lead to repeatable results, as you've so clearly demonstrated Ausglock.

[Ausglock]

Yeah... It's not rocket science.
Just repeatable practices.
My Real job is Quality control for a hardwood flooring manufacturer here is OZ.
I am a bit OCD when is come to processes.

[Taterhead]

Ok guys. Shot about 100 of them in 10mm and 40 SW Glocks. No leading. Accuracy was as expected, which is to say pretty good. I didn't get them on paper. Instead shot at a small diamond hanging plate at 100 meters. They hit it every time when I did my job.

Also did not chrony them since I've shot oodles of similar PC and HT loads of same charge and powder.

But here is the deal: HOLY SMOKES! These loads smoked BADLY. I don't remember commercial cast HT bullets smoking. Just a little of that distinctive smell. That tells me I need to tweak something. Just not sure where to start diagnosing. Hoping for ideas.

More info: both were charged with 452AA. Same powder Ive charged many thousands of similar bullets. Both HT and PC.

40 velocities are about 775 fps and the 10mm are about 850 (yes, modest).

Appreciate it gentlemen. You all habe been very helpful.