Heat cycling molds

[20:1]

Heat cycling also helps draw lubricants from machining the mould from the pores of the metal, along with any minute machining debris. It also helps to "relax" the mould material after all the trauma it went through during machining. Heating in the oven is simple, cleaner, and less frustrating that the old time "your new mould may not start dropping usable bullets for the first few casting sessions" advice.

[Plugs and Muffs]

Ok, here goes...has anyone tried cryotreating a mould? Liquid nitrogen comes to mind. Make those molecules tighten up.

[Chill Wills]

Ok, here goes...has anyone tried cryotreating a mould? Liquid nitrogen comes to mind. Make those molecules tighten up.

What is it again the heat-cycling or in this case, deep-freezing molds is going to do for my bullets? Iron, Aluminum and Brass, I have only cleaned and then cast new molds and they work well from the get go.
A Steve Brooks mold comes with a bullet in the unopened cavity. The buyer is the first to open the mold and see it. Perfect every time; untold thousands of them.
Paul Jones, when he was still making molds, (retired) would cast a bullet form the freshly machined mold, no handles, just a gloved hand and inspected the bullet to be sure he hit the numbers and boxed the mold and bullet up and, in the mail it would go.
I don't intend to offend anyone but I think some things can be overdone.
Carry on. -Chill

[JSnover]

What Wills said!
When casting with a new mold you ARE "heat-cycling." Do it without any lead in the cavities if you want to, it won't make any difference.

[Firesubie]

So maybe the thorough cleaning of the mold is more important than heat cycling? It seems like there are different opinions of the heat cycling and you guys have the experiences to prove your stance on it. This has been a very interesting topic for me. I'm still a newbie caster and learning as much as I can. I really appreciate all the knowledge here.

[Waleone]

I heat cycle brass and aluminum molds to start the oxidation process in the cavities. In my experience, in order for that to occur the new mold has to be spotlessly clean and not smoked or given mold release until after the heat cycling process is completed.

For my steel or cast iron molds, I did not see any benefit beyond cleaning them good and heating them up before casting the first time.

[Good Cheer]

Cryo treating? I'll set one on the front porch and find out!

[Plugs and Muffs]

Not to put too fine a point on it, no one has answered the question. Has anyone tried it?

[JSnover]

I just don't see any radical difference in the time or temperature curves during 'heat-cycling' vs. casting. I know people have done it and half of them gave up on it, the other half always do it. The question was 'what does it do to your mold?' The members who have actually done it haven't told us anything earth-shattering.
My molds - new and used - all started to work better when I learned how to hold my mouth just the right way...

[JonB_in_Glencoe]

Ok, here goes...has anyone tried cryotreating a mould? Liquid nitrogen comes to mind. Make those molecules tighten up.

Not to put too fine a point on it, no one has answered the question. Has anyone tried it?

Plugs,
Welcome to the forum.

I don't think it's ever been done. I've been reading posts here every single day since I've been a member...13 years, and I've never seen it mentioned.
Now, I do think it is a legit question, but your question is kind of buried in this heat cycling thread and only a small minority of members would have seen it. If I wanted to know if someone has Cryo-Treated a mold, I would start a new thread with a clear concise title and a post with some reasoning why you think it might be useful, which would likely breed conversation, and hence keep the thread near the top of the forum for a while.
Good luck.

[Wooserco]

I just don't see any radical difference in the time or temperature curves during 'heat-cycling' vs. casting. I know people have done it and half of them gave up on it, the other half always do it. The question was 'what does it do to your mold?' The members who have actually done it haven't told us anything earth-shattering.
My molds - new and used - all started to work better when I learned how to hold my mouth just the right way...

This, right here! Don't forget to squint just so when you look at the top of the new mold sprue puddle! As Geargnasher has stated: Mold (and sprue plate) temperature are everything. Get that right with clean mold cavities, you are good to go.

[MT Gianni]

Motor experts now claim that there is no need to break in an engine with todays manufacturing technology and materials. In the old days we wanted a break in period that brought things up to temperature, circulated lubricants and worked it at varied limits before we took it wide open. I think those principles still apply for a mold.

[Uncle Grinch]

This thread got me to wondering… I just bought two new moulds from Accurate and haven’t used them yet. What if I stuck them in my oven while cooking cornbread at 400 degrees? Can you consider that heat treating?

[Chill Wills]

This thread got me to wondering… I just bought two new moulds from Accurate and haven’t used them yet. What if I stuck them in my oven while cooking cornbread at 400 degrees? Can you consider that heat treating?

What if you just stuck one in the oven and not the other and let us know what the difference is when casting?

[Uncle Grinch]

What if you just stuck one in the oven and not the other and let us know what the difference is when casting?

Good idea… I can do that. Hope I remember it though.

[ascast]

I was going to comment, but I think I won't...

[Gunslinger1911]

I guess I'm just old school. I toothbrush with acetone, boil in dish soap scrubbing with said toothbrush.
Really seemed to help with Lee alum molds.
My MiHec brass ?? Just a habit I guess, Although, I think it can't hurt to "boil out" all the machining oil.

[MT Gianni]

You would not want to eat what ever gets cooked off of a mold.

[Uncle Grinch]

What if you just stuck one in the oven and not the other and let us know what the difference is when casting?

Well, I had some time this afternoon and tried my two new Accurate moulds, one for the 7.35 Carcano, which I heat cycled 4 times earlier this week and the other was for my 9.3x57. Both are PB and while they both cast good the heat cycled 7.35 really performed better in my opinion. It seemed to release the Boolits sooner and easier. Not exactly scientific as it just my judgement.

[Chill Wills]

Thanks for doing that. This is good to know. Next time I have two new molds, I will give it a try.