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More current info (2018) on Torch V. Furnace melting for casting


#1

Hey there everyone,

I just got back from 2 weeks of intense one on one casting lessons, after having some previous experience. Looking into different torches (was going for larger than my little smith torch - propane/oxy for silver and gold casting) somehow led me to Metal Melting Furnaces. I’ve looked through several Ganoksin articles and other feeds referencing obsolete melt ovens, with many leaning to both sides.

I am wondering if anyone has had recent experience with RECENT USE of melt ovens that would support the use of one or preference of the torch after using newer model of oven? Brand/model preference?

I was taught using the propane/oxy torch method. I have a Smith Little Torch (oxy/propane and useless for casting) as well as plain acetylene (larger torch for larger soldering/annealing purposes). Also wondering if anyone has used plain acetylene for melting to cast? Kind of crazy to have so many tanks and torches in my little space…

Thanks for your insight.
Elizabeth


#2

Elizabeth,

you might want to watch the orchid video “Casting of small series of jewelry”. The propane/oxy torch shown in action is available for melting silver + gold (up to 450g) or stainless steel + platinum (up to 150g).

Schmelzen-CastT-400

Handle 4 6

Both are very useful for “soft” applications like annealing, too. This professional tool is offered by several renowned suppliers.

Sandor


#3

I much prefer my digital read out computer controlled melting furnace. I can set the temp and not have to worry about over heating or under heating my metal. It will go up to 2100 F which is plenty for gold or silver. Not hot enough for platinum. It makes an inert atmosphere down in the graphite crucible so the metal stays very clean. And you don’t have to juggle a torch while getting a flask out of the oven. It is perfect for vacuum casting but not for centrifugal. I gave my centrifugal casting machine away years ago. Too dangerous and I can put much larger flasks on my vacuum caster


#4

Thank you Sandor.
So it’s safe to assume you are more in favor of the torch? Have you ever used a melt machine?
Thanks again.
Elizabeth


#5

Thank you, Wade

Have you had any issues with other melt machines? How old is yours? And what Brand, model?

I wish more people jumped in on this conversation. The older posts are from 2005 and 2012, I believe and there has been upgrades and additions to the melt machines from then.

Thanks again for your help!
ELizabeth


#6

Mine is an off brand chinese made 1 kilo capacity. I have been using it for 5 years. The one I had before I think was an electromelt that was not digital. It lasted about ten years. You can replace the heating elements on them but it costs more than 1/2 the price of a new one.


#7

Elizabeth,

the plain answer is: no. There are more facets to the answer you are looking for. In my dental lab we run a vacuum centrifugal titanium casting machine with an arc melting feature, a vacuum casting machine with induction melting and a centrifugal casting machine for flame melting. From a physicist’s point of view, backed with this set of means of production, the best choice for dental (or jewelry) size casting is a vacuum centrifugal casting machine with induction melting. From a shop manager’s point of view, the mid-size five digit asset required for this is not everybody’s collar size, compared to a broken arm centrifugal casting machine for flame melting. With these constraints it is obvious that everything being used in a shop is a compromise in between.

When we started operation with a broken arm open flame casting machine we always wondered why such a big space is wasted for casting of such a small amount of metal. Not to mention what happens if the broken arm is not balanced properly. It took a few months to develop our approach to lost wax centrifugal casting which is registered under US Pat. # 6880615 and others. By this approach we reduced the space required down to 1/8th of a conventional broken arm machine with a capacity of up to 450g gold without the need of balancing. The self-contained housing makes it one of the safest centrifugal casting machines, as long we are not talking of turbine parts or engine blocks. From a technical point of view, it’s easy to mount this arrangement into a vacuum chamber with an induction coil, but the price tag for such a system would significantly reduce the target customer base in two niche markets. Melting with a resistance heating unit was never an option because of the constraints of melting temperature, hence the torch option.

Back to the roots of your subject: if you are afraid of a heavy duty flame and fine with the temperature range of a resistance heating furnace and are willing to wait until it reaches casting temperature: go for the furnace. If you don’t want to waste your time waiting for the right temperature and trust your experience in your eyes and fingertips: go for the (right) torch. If a vacuum centrifugal casting machine with induction melting is in your budget: by all means, go for it.

Always keep in mind: no customer of yours will ever ask how his/her piece of jewelry was made.

Being in business for decades now, there are two lessons I learned the hard way: the best product of its kind ever is worth nothing if nobody is willing to buy it, and life is not a bowl of cherries. My 2¢.

Sandor


#8

Sandor, spoken by a true ‘Magyar’ Hungarian. Regards, Richard Lucas…another true Magyar…:grinning:


#9

You know, Richard, one of my favorite Hungarian sayings is: Most ugrik a majom a vízbe. (Which for those unfortunate souls who don’t speak Hungarian means: “Now the monkey jumps into the water,” an idiom for “let’s see what happens.”) I often say this when attempting something new or risky at the bench.

Alec


#10

I appreciate this, as my main issue was brand. Reviews are all over the place.


#11

Thank you. I do have a vacuum casting machine and would like a melt machine. I’ve checked out several and reviews are all over the place, with claims of not keeping consistent temps, etc. This was the main reason I asked this question. Hard to pick one!
Thanks again.
Elizabeth