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Electromelt furnace


#1

Alma,

I have used an electro melt for 30 years. Its use allows you to
maintain a consistent temperature between pours.

Without the pour assist on the vacuum table the electro melt makes
pouring easy. Just like pouring coffee.

There is a furnace on the market that I wold strongly recommend not
buying. It is much cheaper but is not as easy to use as the electro
melt. It requires you to remove the crucible with tongs from the
furnace unit. This is a very awkward method.

I now use the large electronically controlled unit. I fill the
crucible with as much silver as it will hold. I pour until the
remaining silver looks like it will not fill the next mold. I fill
it to the top again and start over.

This cycle will work with the smaller electro melt if the models do
not require large amounts of metal.

Several precautions:

  1. Do not pour the metal for at least 5 minutes after the unit
    reached the temperature you have set. This will give the upper ring
    of the crucible enough time to heat up and not to cool the metal as
    it is poured. If you pour too soon the cooler ring will chill the
    metal as it is poured.

  2. Allow at least 5 minutes between pours again to allow the ring to
    heat up.

  3. Weigh and record the amount of metal each flask will require
    Record a number for each flask. Scratch the number on the non sprue
    end of the invested flask. Record where they are placed in the burn
    out oven. You will know which flask you are pouring and how much
    metal it will require. Knowing how much your are pouring and how much
    you had in the crucible will tell you how much metal is still in the
    crucible available for the next pour.

  4. If you do not buy the electronically controlled unit be sure to
    monitor the temperature. The unit will burn itself up if not
    controlled by you. When I used the not controlled unit I would set a
    timer and clip it to my shirt to remind me to check on the electro
    melt.

If you are pouring sterling silver be sure to check on my anti-fire
scale casting procedure. You will get castings without fire scale.

http://ganoksin.com/borisat/nenam/vacuum-casting-firescale-
prevention.htm

Contact me if you have any questions

Good luck
Lee Epperson


#2
There is a furnace on the market that I wold strongly recommend
not buying. It is much cheaper but is not as easy to use as the
electro melt. It requires you to remove the crucible with tongs
from the furnace unit. This is a very awkward method.

Well, I’ll disagree with that. I have an electromelt AND one of
those italian furnaces which just sit on the table, and you remove
the crucible with tongs. Frankly, I find it much easier to lift the
crucible out, than to manhandle the much greater bulk of an entire
electromelt furnace. The crucible pouring lip can be held closer to
the flask without that whole furnace still around it, and it’s
lighter too. And the modified pliers they use as tongs provide a
good secure grip on the crucibles. By contrast, with my electromelt,
I’m never quite sure just how far I dare tip it before the entrie
crucible literally falls out of the electromelt. That happened to me
once. And you have to juggle with holding the lid open too. And I
prefer the crucible types too. The electromelt crucibles have this
probe thingy up into the bottom of the crucible where the
thermocouple sits. Supposedly, that should give the electromelt a
better accuracy on the metal temp, but I’ve simply not noted that to
be the case. The italian melter crucibles have a simple flat bottom.
They hold a bit more metal, and are easier to clean, as well as being
sometimes slightly cheaper to buy. I think, but I may be wrong, that
they seem to last slightly longer too, though this would depend some
on the quality of the graphite crucibles you buy. As I said, I
think, and I might be wrong, that the temperature accuracy on the
italian furnaces to be a bit better too, perhaps because of the
simply larger cavity in the furnace that’s brought to temp. I’d been
using both the electromelt and the italian furnace for a while. The
electromelt I’d bought new, while the italian furnace was used, a
LOT, and looked it. The electromelt burned out several years ago,
while the italian furnace is still going strong despite it’s age and
mileage. If the electromelt has an advantage, it’s in it’s greater
portability, since you can bring it more easily to wherever your
casting setup is, while the italian type furnaces kinda want a
semipermanent home, at least while your using them, and pretty close
to your casting/pouring location, since you don’t really want to be
walking around long distances with a red hot crucible… (the one we
have at work is brought out from a shelf for casting, and put back
afterwards, without waiting for it to cool (the outside stays cool),
so it’s still portable. But not quite as much as the electromelt. But
this is still not enough for me to bother fixing that electromelt…

cheers
Peter


#3

To all, another 2 cents…

I too have both units. I prefer the electromelt. I like the
simplicity of the unit. Removing the crucible in the Italian model
has been difficult only when the crucible is old. I pinched the top
right off one time with the tongs provided. The top on all of the
crucibles will wear with time.

Each metal should have its own crucible. Don’t use the same crucible
to melt gold and silver. Some metal will always stick to the inside
of the crucible.

I started casting in 1971. My electromelt was purchased in 1977. I
still use it. The element went out only one time I keep a spare on
hand. Parts are still easily available. This is the smaller unit and
not a digital one.

When pouring you simply press the stirring rod on the top of the
graphite crucible to keep it in place while pouring. It will never
fall out that way.

The electromelt graphite crucible is available with a flat bottom on
the inside. I think it is available from Gesswein.

Temperate is confirmed by my fluxing & stirring, not just the temp
gage. I routinely pour at 2100 which is over the temp capacity of the
unit with no problem. The deox metals all need a little more heat.

I regularly cast 150 to 200 dwt with no problems. I prefer to spin
cast smaller amounts under 100 dwt with an old HR casting machine
from 1974. The spring has been replaced on that unit once also.

I use the Italian furnace at school, but would only purchase an
electroment if needed.

Regards,
Todd Hawkinson
Mpls Comm & Tech College


#4

Peter,

I have both and have used the Italian furnace exclusively for many
years, the Electromelt design is very poorly thought out and
impractical for any production casting. The Electromelt is also
unreliable for production use. The Italian furnace I used for years
never failed, The Electromelt has been down for most of 20 years.

Sincerely,
James McMurray


#5
I have both and have used the Italian furnace exclusively for many
years, the Electromelt design is very poorly thought out and
impractical for any production casting. The Electromelt is also
unreliable for production use. The Italian furnace I used for
years never failed, The Electromelt has been down for most of 20
years.

sounds like we’re on the same wavelength here, James. And my italian
furnace is still going strong. You’ll recall it’s the same one you
say you used for years before selling it to me (thanks) a number of
years ago. Still looks as beat up as when you sold it to me, and
still works just fine. Prolly will outlive both of us.

cheers
Peter


#6

There are three electric melting furnaces that I’ve used but there
are several on the market. The Electro-melt, the Italian made one
that sits on the table where you remove the crucible to pour and the
Jelrus that is available from Romanoff. I’ll give an opinion on each
one, I’ve done side by side comparisons in my shop.

The Electro-melt is a very good and somewhat expensive machine. It
heats much slower than the other two. They all over shoot the set
temp. so one must be vigilant when using these furnaces to avoid
"cooking your melt." The Electro-melt by Kerr also has a feature when
the lid is lifted it stops heating. When pouring I would use a
graphite stirring rod to gently hold the crucible in the furnace.
There is a larger 100ozt model available but I haven’t used that
one.

The Italian furnace where one removes the crucible is also a very
well made machine. The thing that I didn’t like about it was the
actual removal of the graphite crucible. The crucibles degrade when
they are hot and exposed to air. Over repeated pours I noticed with
the Italian furnace the crucibles didn’t last as long as with the
other furnaces because of the complete exposure to air. Rio Grande
also has a furnace where you remove the crucible. It is about the
same size as the Electro-melt and the Jelrus.

The Jelrus is probably going to be the least expensive to buy and in
my humble opinion the best bang for your buck. It use to have a
detached lid that was well… crappy. They redesigned the lid a
couple of years ago and it is now attached much like the electro-
melt. It heats up much faster than the Electro-melt and about the
same as the Italian furnace. I have had the graphite crucibles crack
and leak molten metal into the furnace chambers on both the Electro-
melt and the Jelrus but I just poured the metal out into an ingot
mold. The damage was negligible to the furnace though there was a
mess to clean up. Keep an eye on your crucibles. It’s a game of how

many pours you can get out of each one. I have used several
different graphite crucibles from different manufactures. The big
difference seems to be the thickness of the collar around the top. I
do believe that the Kerr ones are more expensive but they are better
made.

All in all you won’t go wrong in buying one of these furnaces if
that is the way you want to go. I have never had any tech. problems
with any of them, we just don’t use them in our shop. They are too
small and too slow for our production purposes. One last word is get
the digital/automatic model and not the manual model, you’ll be
kicking yourself if you don’t.

Steve Slaughter
AlchemistCasting.Com
Platinum - Gold - Silver - Bronze


#7

My 1kg italian furnace takes about 90 minutes to come up to temperature when melting silver - is this normal ? I have only used the unit about 10 times over the last 10 years because of this.

thx