Flame annealing

[WIZARD6787]

Hello,

I am a hobbyist at best. I make marbles by mashing COE 104 together and that is it. The largest I make is 1 1/4"

I want to buy a hot head torch. Flame anneal the marbles by getting it bright red and then cooling it in the flame until dull red. Then put it in a crock pot with dried vermiculite on high for an hour then cool in the crock pot.

Any guesses about the likelihood of success? I know there is a lot of stress in my marbles as I mash all sorts of colors together.

Normally I would just try it and then drop the marbles on concrete. Thing is I need to make 20 marbles for my daughters wedding and only have 5 days to make them when I get back to the USA from the UK

[ESC]

Number 1. making a 1 1/4" marble on a Hot Head is going to take forever. Number 2. making anything over 1/2" or so and expecting it survive after cooling in a crockpot is a crapshoot. Technically, you can cool them in the crockpot of vermiculite, but that is not annealing and their long term survival is questionable.

Does anyone near you rent bench space with access to a Minor or similar and a kiln to anneal those marbles? That's what I would be looking into. Good luck!

[WIZARD6787]

Thank you that is just what I was looking for. I will buy a kiln.

[ESC]

You're welcome and good luck!

[KJohn]

agree with all that, no such thing as flame annealing when you want them to last. It's a mis-named term for evening out the heat, sometimes folks get touchy even hearing that word but everything has its place.

A kiln is the best thing. Good luck! and Congratulations Post some pics in the gallery if you like.

[rainygrrl]

Kiln is a great decision! In some cases, probably rare, a piece that has not been properly annealed can break years later.

[rcktscientist]

Alternative kiln idea:
Buy a Plug & Play PID ramp controller box for a 120v kiln ~$250
+ buy a ceramic thermal stove (for hot combs) ~$50
+ buy 1 sq. ft ceramic fiber blanket ~$20

$320 plus some time cutting the fiber blanket to create a 'door' and a little more time reading the manual and programming, then you can properly anneal marbles to your hearts content. That little oven probably holds at least 10 marbles. Perfect investment/cost/complexity for a hobbyist. Just be safe and smart with high temps and airborne blanket fibers.

[AVTrout]

I've had my Paragon Bluebird kiln for 17 years and it still works fabulously. A great investment!

[Sue in Maine]

Originally Posted by KJohn

agree with all that, no such thing as flame annealing when you want them to last. It's a mis-named term for evening out the heat, sometimes folks get touchy even hearing that word but everything has its place.

A kiln is the best thing. Good luck! and Congratulations Post some pics in the gallery if you like.

Thank you, thank you, thank you. Every time I see that term I have to fight myself NOT to say anything. You said it for me! Thank you!

Sue

[KJohn]

I know, right? WE know what it means but it always gives someone new the wrong idea.

[kevingreenbmx]

In the furnace glass world, I was taught the term "flashing down" for evening out the heat base in a piece after finishing working it before it goes in the kiln. That's what I try to refer to it ass when I teach new folks on the torch as well.

[rcktscientist]

Just a quick scientific explanation:
Cooling glass generates stress from temperature gradients. Thermal stress
After working, evenly warming your piece in the flame, then also evenly cooling it in the flame will reduce stress since you are minimizing the temperature gradients. Less gradient, less stress.
It won't reduce it to acceptable "annealed" levels but there is some reduction. The slower you cool, the more reduction of stress but never quite annealed.
Even "annealed" glass has some thermal stress, its just at an acceptable level so no real risk.