I have a nice square sandcastle bucket.Next batch when I get new chemicals...
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Mark
Understand following instructions. Very important.
It's funny how most everyone carefully measures out the amount of solution to coat the bullets with. I put about 5 pounds of bullets in a square bowl and squirt for about 2 seconds straight out of the squeeze bottle.
I suppose the humidity in my shop is not very high as mine are dry in about 10 minutes. I do set them on my toaster oven for 15 minutes to preheat. This procedure has worked for me and I understand different climates make a difference.
I am by no means a guru so take this for what it's worth: It appears to me that your heat is either too high or cooked too long, maybe both, just judging by the color. My green turns brown if I cook it too long.One other observation is that the lead looks pretty soft.
Have you tried a different color?
I feel confident that you will eventually get this straightened out and be a happy camper.
I have some different acetone and some MEK on order.
its 25c in my garage,but I haven't considered the humidity.I think it's the acetone cos the mixture didn't warm up initially...
Hang in there Mark, one day soon it will all click and work great, and you will have no idea why. That's because you are close. You will only need MEK if you are trying to slow down evaporation.. AusGlock and myself have to fight near 100 deg heat in summer and ,trust me it flashes off fast over here.
For whatever reason, you have confirmed that more drying produced better results.
One area we have not addressed is, that the Acetone you are using may have high Water content.
That will certainly not help at all.
Combined with excessive moisture, that reduces drying, aside from poor drying, this moisture can also react with more "active" contaminant metals, that will also react with the coating, that may also cause adhesion failures.
For all the problem indications so far, I am suspecting drying as main cause, Acetone quality is also high on suspicion list, and to a lesser extent, possibility of alloy being contaminated, and a possibility of all 3 as contributing factors.
I refer back to my previous blog, where I advised, that moisture, heated from room temperature to 100C, expands about 1000 times original volume. You don't need much moisture to cause problems such as experienced.
If there is trapped moisture inside coating, when placing this into an oven, the moisture will travel towards cooler surface (being the alloy). Heat expands vapour, steam/vapour lifts the coating film off alloy, heat cures lifted coating, but there is no bonding to alloy, as lifted film is supported with a steam layer that is formed between alloy and coating. The lifted film is heat set.
Upon cooling, coating is set, but poorly or not bonded. Typical tell tale sign/appearance from moisture entrapment, is blistering or small bubbles that are set and visible in baked coating after heat cure.
I did request, that you carry out a controlled test in my blog 7956.
I am keen to get your results from my suggestions.
MEK is more forgiving to hotter climates.
You do not need MEK down in Sheep shagger land.
When you had the coated bullets in front of the fan. Was the fan a heater fan or a normal old fan?
Placing the bullets on top of a wall oven to pre-warm is useless. They are too well insulated to do any good. This is why you use a fan heater.
Hi
Trev said I burnt them.Attachment 18482710minutes at 200C
Attachment 18482812 minutes at 200C.
I left them overnight after baking and the coating seemed harder to scrape off,but I could still scrape it off so I failed.
I've just done some more of the batch I coated yesterday,so they've been drying for 24 hours.
7 minutes at 200CAttachment 184829
8 minutes at 200CAttachment 184830
Attachment 184831This is the HT mix that's been sat for 24 hours,does that look right???
the 7 and 8 looks close.
Yep. the coating settles out really quick.
That is why ya gotta remember to shake it all the bloody time.
Do you have Bunnings down there? Get yaself a fan heater. cheap and will make the difference.
I think I paid $12 Aud for mine new. I'll get some photos of my drying tray rack and fan setup later this arvo for ya.
I think your right about needed new acetone.
Do you have a fan blowing over / under your bullets helping them dry?
When you do test bakes, you need to had the full 250 bullets in the oven, all but 2 or 4 of them can be raw and re-used. this will guarantee the proper heat absorption. I agree with Mike, You need a bigger syringe. I would suggest a tube or hose that reaches the bottom of you bottle to suck the hi-tek solution out with. Fill the syringe once and squirt it back in then fill it again to the proper mark.
Buy or borrow an oven thermometer to check temperature on the center of the shelf your baking on.
Hang in there.
Like they say when everything clicks you'll be able to hi-tek coat in your sleep and be glad you stuck with it.
I have Kryptonite Green, Zombie Green, Dark Green, Bronze 500, Black, and Candy Apple Red. For me the Zombie Green has been the hardest to get right. Anything with the sparkly flakes in it will settle out really quickly. Filling those from a syringe is problematic for me. Fresh acetone and a different color may give you a very different result. Just saying.
When you make the hitek,how warm does it get on initial shaking?Mine didnt warm up much at all.
I never noticed any change in temperature. I shake really well with 2 bullets inside to help mix and squirt about 2 seconds later. That is with a solution that has been properly mixed. Too little is better than too much as more coats will build and color will get darker.
Here is my Pre-Bake fan heater tray rack.
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