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Casting torch ingots


#1

Hi All, I’ve finally set up my torch, and am in the process of
learning how to use it. Of late, I’ve been casting ingots and bars
and have a question concerning that; Do I cast into a hot, warm or
cold ingot mold, and what are the reasons for doing it?

Richard, in rainy Michigan


#2

Richard: It is important to heat your metal mold to burn all the
moisture out before pouring your melted metal into the mold. Your
can see a color variance on the cast iron molds as the moisture is
burned off. The least amount of moisture in a mold can be very
explosive when the melted metal is poured into it. My old instructor
had a student lose a eye when hot metal drops blew up out of the mold
due to not heating it to remove moisture.
It is surprising how porous metal really is.


#3

G’day; I suggest that the moulds should be fairly warm to hot. This
will help the cast and ensure that when you pour in the hot metal it
doesn’t meet with moisture, turn it to steam so the molten metal
comes shooting out at you! –

Cheers for now,
John Burgess; @John_Burgess2 of Mapua Nelson NZ


#4

Hi Richard:

Here’s how I use my little double sided (round wire or flat sheet)
ingot mold.

  1. Warm the mold with the torch untill it’s too warm to comfortably
    hold on to.

  2. Lightly oil the inside of the mold using a cotton swab and
    machine oil or spray it lightly with “Pam” or another cooking oil
    spray. Just the lightest coat possible, no dripping oil.

3 I light my torch without turning on the oxygen. Just a big,
bushy orange gas flame. A candle will work too.

  1. Holding the mold in the flame (with pliers if it’s too hot), I
    cover all surfaces with soot from the flame.

  2. Assemble the mold and heat it up again till once again it’s too
    hot to touch. You can test it with a wet bit of cloth. If the water
    hisses a bit, you’re at about the right temperature.

  3. Melt, flux, and pour your metal into the mold. Let it cool
    enough to handle it, and you’re done.

I’ll let someone else explain why it’s done that way. I just know
it works for me, and I’ve tried it skipping some steps and didn’t get
as good results.


#5

I’ve always ‘torched’ my ingot mold with fuel only first(ie:
acetylene) with produces a very smutty carbon that coats the mold
well.This allows the molten metal a ‘cushion’ between the iron ingot
mold and helps the metal flow much better. But it’s a nasty job! Use
good ventilation! I also heat mold with a torch a bit and angle
reflected flame toward ingot mold while torch melting metal. A 'cold’
untreated pour may trap air and ‘spit’ out metal and is potentially
dangerous. Hope this helps

Thomas Blair


#6

Try using High temp silicone mold release on a extremely clean
mold, Heat lightly and pour. It works for us and is alot cleaner than
"sooting" your mold and bars & wire come out bright & clean. Also
watch your pour temp and if you have problems that wont go away try
using different alloys until you find one that works.

Anthony Prime
Prime Recognition


#7
    Of late, I've been casting ingots and bars and have a question
concerning that;  Do I cast into a hot, warm or cold ingot mold,
and what are the reasons for doing it? 

Hot. One of the major constituents of the resulting gases from a
torch is water. This water will quickly condense onto cold metal. In
the case of a metal mold, when hot metal hits this condensation, it
vaporizes immediately resulting in sputtering metal. I have worked
with jewelers that have refused to believe this, and I have watched
them spending many hours in the “jewelers position” picking little
metal bits off of the floor. It could have been a lot worse.

I like to lubricate my molds with olive oil. When burned into the
mold, it provides a layer of carbon that keeps to two metals apart
and seems to allow more even cooling.

Bruce Holmgrain
JA Certified Master Bench Jeweler
http://www.goldwerx.com