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Neycraft centrifuge problems

I guess they used what was available to them at that time. You can
even try steam casting or sand casting too! I was just speaking from
32 years of experience of using both methods and do not think
speaking ones opinion would be called out for being irresponsible. I
know many artist that swear by it but if someone does not do it all
the time centrifugal can be a gamble. I have worked at a custom shop
that had the system and it was 50 50 at best. Taking things out of
context is pretext with out all the facts. There are people who come
to this forum for advise and not have someone look down on them for
trying to learn and enjoy jewelry making. To be blunt I guess I can
send up smoke signals and beat some drums to be a purist to get the
message out from my experience, but oh no it is 2010, the twenty
first century, Dorothy your not in Kansas any more and like it or not
technology moves on and I am using this thing called a computer to
"share" my experience in both methods. Sorry for being irresponsible
for my opinion but after seeing hobbyist get 3rd degree burns from
trying something that spins with a loaded heavy spring that is kin to
pulling a pin on a grenade holding a torch and ducking to make sure
you do not get slapped with molten metal all with in a micro second,
calling it irresponsible, I do not get it. What centrifugal casting
machine manufacturer company do you work for??? Just because you
have had a good results from your method does not mean it is good for
others. What would you suggest for a beginner? I apologize for being
being upset with the comment but really, the Mayan and Aztec Indians
comparison does not make sense in todays world. Again I apologize but
I am trying to think of what mind set the comment is coming from. I
can go to a web site for but use electricity and a vacuum
motor is not being true to the art??? Sorry, out of line

Alma:

I did not realize from the posts I read that you were not using a
Neycraft crucible. The regular Neycraft crucible is very different
from all others I have seen. The two short rods need to fit
relatively tightly into the grooves and will then be very secure. I
doubt that you can modify any other crucible that I have seen in a
way that would make them secure. Just order one from Neycraft. They
are not very expensive. I think a loose crucible will be very
dangerous

Fred

The replacement crucibles for Neycraft casting machines need lots of
adjustments to fit into their machines. You need to grind out the
bottom of ther crucible so it will actually slide into place, and
usually the end of the crucible that fits through a hole. I like
their machines, for ease of use, but whoever designed their
crucibles needs to go back and try again. I probably spent 1/2 hour
on each crucible to get it to fit correctly ( and safely) into the
Neycraft caster.

Jay Whaley

Jay and Fred,

Thanks for the about the replacement Neycraft crucibles.

The New crucibles which I just ordered from Otto Frei are due to
arrive this coming Tues.

I hope they will not need adjustment. Frie advertises them as the
only ones that fit the Neycraft 4X4. I did notice that the number on
the crucibles is NEW part 9353005, which is the same number on the
parts list in the manual that came with my Neycraft.

Hopefully, they will fit perfectly and not need all the grinding and
adjustment you have had to do. They should fit correctly or it is a
safety factor.

If they don’t fit, I shall return them and contact Neycraft about
the problem. It is really up to them to produce a product that is
safe.

Thanks again for the
Alma

but to speak this negatively about a process that has been around
for centuries is a bit irresponsible. 

Just curious what form of centrifugal machine has been around for
centuries? As far as I know Dr William Taggart invented the
centrifugal casting machine for lost wax casting in 1907 for making
dental prothesis.

Jim

James Binnion
James Binnion Metal Arts

Centrifugal Casting IS an art and really shouldn’t be done by
hobbiest. That’s what they make clay casting kits for. “What
centrifugal casting machine manufacturer company do you work
for???”

I don’t work for a supplier of casting equipment, I just happen to
know what I’m talking about. “I have been using spin casting for over
20 yrs. and never had ANY serious problems.” I am a manufacturing
jeweler I do this for a living as a professional with proper
training, NOT a hobbiest.

I suppose you may be the type to take their kids to a public pool
and throw them into the deep end after only 1 swimming lesson, then
complaint that the water was too deep! Casting is like gourmet
cooking. If you get just one element wrong it will effect the whole
process!

Sorry you felt insulted, but next time, be a little bit more
informed before condemning an ART FORM.

I know I was a bit hasty in my response for being called out for
being responsible. Three are a bunch of people who very rarely have
any problems with centrifugal cast and I know that "newer machines"
and setups are out there. My problem is I am a person who has in the
past helped newbies learn different aspects of making jewelry and
some have wanted to cast. Vacuum casting done right has less of a
fear factor IMHO. If I hade the choose when first starting out I
might be using centrifugal. I think it comes down to what you know
and have been doing for years, it becomes second nature. I see a bit
of “rookie” questions that leads me to believe that the one asking
the question is just starting out and wants to learn. This forum is
the one I point to when some one wants to get an Idea of the how do
you question. I get many questions from other jewelers who have been
in it a while that I think they should know by now and just never had
the curiosity or desire to give it a try.

I just felt to a beginning caster, vacuum is the easiest to learn
and not the best or worst, just different. I have done both and seen
the results of both. I am in a position that I am called on to use a
customers metal and we all know how that goes, not enough button and
metal to “throw” the cast. The spinning of the flask keeps moving and
the metal is still molten with this going on where as vacuum the
metal is poured into that flask an stays immobile for the cooling or
a least five minutes to get ready for the nest flask. For those who do
centrifugal, find a buddy that does vacuum and ask if you can stop by
when they are ready to throw their cast just to get a different
perspective. I appreciate Richards opinion, he know what he is doing
and if it is not broke don’t fix it but if you are having trouble
with something and make a living from you need to find something that
works.

Carl

Just curious what form of centrifugal machine has been around for
centuries? As far as I know Dr William Taggart invented the
centrifugal casting machine for lost wax casting in 1907 for
making dental prothesis. 

One might point out that vaccuum casting is also a rather recent
innovation. Used to be, if it was cast, it was gravity cast. In
sand, clay, or some version of investment, but still, a simple
gravity pour. Lost wax casting is the technology that’s old, going
back at least to Roman times and perhaps earlier. But those were
poured simply via gravity assist. The increased accuracy and detail
that’s easy and possible with newer methods is in large part
responsible for the fact that most jewelry these days is cast. The
old sand casting methods were OK for what they were, but certainly no
competition for today’s casting technologies, nor able to give
fabricated work any real competition, which modern casting does, at
least commercially, now do.

Peter

The ancient Indians of North America used clay pots over open fires
to burn out models, then they would take wet vines and tie them to
the pots and then swing them in a circle like pitching a baseball
underhanded to create a centrifugal motion, thus the gold was "SPUN"
into the pot for a casting. "Research " people! RESEARCH!

I’m sure the idea just POPPED into his head one day over a bowl of
cereal. LOL

Vacuum casting done right has less of a fear factor IMHO. If I hade
the choose when first starting out I might be using centrifugal. I
think it comes down to what you know and have been doing for years,
it becomes second nature. 

Since this thread has taken a turn from a falling crucible…

There’s a point where vacuum is essential - large pieces that really
won’t go in a centrifuge - and then there’s a point where you can’t
even vacuum, and it has to be gravity. Speaking of sculpture and
large bells and ship propellors and the like. I knew someone who had
an eight foot long ce ntrifuge that took 12" flasks, but that was
custom made…

Anyway… I guess there’s some place where a lab can find some
difference in metal in each of the methods, but for making jewelry I
have found that it’s six of one and a half dozen of the other.
People who vacuum think it’s best, and people who spin think IT’S
best, and now and then it actually turns into a dispute. Having
worked on the products of both methods for 40 years (and being
around it all, too), I can see no real difference between the two -
that is if they are quality castings to begin with… For most of our
average, general purposes it’s “I like the butter on this side of
the bread, no, it goes on the OTHER side…”

One might point out that vaccuum casting is also a rather recent
innovation. 

Yes that was my point. Prior to these modern innovations the detail
achievable in a cast object was limited by the weak force of gravity
on the metal.

ames Binnion
James Binnion Metal Arts

Jim:

The early dental casting was done by swinging the flask in a circle
over the head on a chain. Sounds dangerous, doesn’t it? Same as
swinging a bucket half full of water over your head. The centrifugal
force hold the water in the bucket and forces the metal in to the
mould when casting. There is a picture in Tim McCreight’s book “The
Complete Metalsmith.” He calls it “sling casting.”

Lost-wax casting was apparently invented in several places around the
world independently. I have seen no good evidence about ancient
methods or whether centrifugal casting was used before Dr. Taggart
started it. Some ancient pictures show various forms of gravity
casing in use. The Ashante casters in Africa have been using
primitive methods with a unique form of gravity casting that I
describe in my book. The Greeks were experts at lost-wax casting
along about 450 BC. Most of the pictures I have seen show gravity
casting.

Hope this helps,
Fred Sias
www.woodsmerepress.com

The Neycraft crucibles that I ordered from Otto Frei arrived and
they fit the centrifuge perfectly. They don’t need any adjustment or
special treatment.

Each came with a label which said “genuine Ney crucible,” and in the
Frei catalog are listed as stock number 9353005, which is that same
as that in the Neycraft manual.

I have since learned that there are a lot of crucibles being sold as
fitting the Neycraft.

However,many don’t fit and need a lot of adjustment. The necks are
the wrong shape and size, and the bottoms drag on the crucible
slider.

One red flag when purchasing these is that the fake ones are much
less expensive than the genuine ones, ranging in price from $9.00 to
$14.

I paid $25 each for the ones I got from Frei and they are worth it.
Now to get them properly prepared with borax and back to casting.

Thanks again to everyone who made such helpful suggestions.
Alma

The early dental casting was done by swinging the flask in a
circle over the head on a chain. Sounds dangerous, doesn't it? Same
as swinging a bucket half full of water over your head. The
centrifugal force hold the water in the bucket and forces the metal
in to the mould when casting. There is a picture in Tim McCreight's
book "The Complete Metalsmith." He calls it "sling casting." 

Quite familiar with it, tried it a few times out of curiosity, it
worked ok but it is not needed when one has either a centrifuge or
vacuum casting unit. But I am not certain this predates the Taggart
centrifuge and I would guess that if it predates it it is not by
much time. For one thing without a gas torch doing sling casting is
nigh near impossible and such torches are also a relatively recent
invention. If one tries to pour from a crucible into the sling then
start swinging it the metal will freeze before you even begin to
move, it is the super heat of melting in the flask mouth and the
small diameter feed sprue that prevents the metal from flowing till
there is enough force to overcome the surface tension that allows
sling casting to work at all and this would be very hard to do
without a torch.

Lost-wax casting was apparently invented in several places around
the world independently. I have seen no good evidence about ancient
methods or whether centrifugal casting was used before Dr. Taggart
started it. 

Lost wax goes back to at least the ancient Egyptians and Chinese.
But the modern form with the centrifuge or vacuum assist are what
really changed the art. Prior to that to get small detail one needed
to chase or engrave the casting after the fact as gravity just does
not provide enough pressure to overcome surface tension for small
fine detail.

James Binnion
James Binnion Metal Arts

Having worked on the products of both methods for 40 years (and
being around it all, too), I can see no real difference between the
two - that is if they are quality castings to begin with... 

John, The differences between centrifugal castings and vaccuum
castings is subtle, but real enough.

First, if your casting has gas porosity, (which it shouldn’t), or
shrinkage cavities/porosity, the higher pressure of the molten metal
in centrifugal casting will tend to make these defects smaller. Now,
either way, they’re defects. If you’re doing things right, they
shouldn’t occur in either method.

Second, Because of the increased force and speed with which the
molten metal enters the mold with spin casting, the mold fills more
quickly. This can make it possible to cast metals that are otherwise
difficult to cast with a complete fill. This is why commercial
vaccuum casting machines don’t try to say they’ll work with platinum,
and the commercially available platinum casting machines are almost
all centrifuges. Platinum is perhaps the prime jewelry metal where
this distinction is important, but it’s there. With other metals,
extremely detailed and fine models will be easier to get to fully
fill with the centrifuge, for the same reasons as it’s used for
platinum. You can get full fills with vaccuum casting by increasing
the flask temperature and/or metal temperature, but there are
drawbacks to this as well. With most models, it does not make a
difference, but there are some, where it will.

Third, again relating to the speed and force with which a centrifuge
can fill a mold, it becomes possible to use a lower flask temperature
than with vaccuum casting. For gold or silver, this is often a
difference of 150 to 200 degrees F cooler. That becomes significant.
Coupled with the more rapid air cooling experienced by a spinning
flask after casting, the lower flask temperature means the cast metal
will have a finer grain structure. This is not something you visually
see in the casting, especially once it’s cleaned up. But it directly
relates to the strength of the metal. Finer grain structure is
stronger metal. The degree to which this difference occurs, and the
degree to which it makes a difference, is entirely dependent on the
metal alloy being used.

As I said, it’s subtle. You cannot see the differences (other than
if you’ve got bad porosity) in the casting, much less the finished
item. But the spin cast metal can sometimes be distinctly stronger.
Key word there is “sometimes”…

Peter Rowe

Steve,

The ancient Indians of North America used clay pots over open
fires to burn out models, then they would take wet vines and tie
them to the pots and then swing them in a circle like pitching a
baseball underhanded to create a centrifugal motion, thus the gold
was "SPUN" into the pot for a casting. "Research " people!
RESEARCH! 

Do you have any sources for this statement.

I ask because to the best of my knowledge (which may be incomplete
here) most north american native cultures were stone tool users, not
yet metal using ones, I’m curious just where this casting method was
used? So far as I know, metal working north of the Yucatan
peninsula/central america didn’t appear until after the arrival of
europeans, and even then was largly limited. And while central and
south american cultures certainly were metal working (as in, all
that wonderous gold…) I don’t think I’ve ever seen any evidence of
a spin casting method. I’d love to see the references.

Peter Rowe

Hah…take a class with Harold O’Connor and he will do “Sling
Casting”. Pretty impressive!

I do both Vacuum Casting - The caster is called “Aquavac” Excellent
little caster; and Neycraft Centrifuge casting. Have never had any
problems with either.

I used the same model Neycraft mentioned in this post in teaching
Lost Wax Casting at Ghost Ranch for several years. Always good
results. And during the time I was teaching the Adult Ed classes, we
had a humongous caster in a barrel filled with cement! It was a great
item.

I am a pretty experienced silversmith with years under my belt, but
there is never a day that I can’t learn something new from this
group.

Thanks a bunch
Rose Marie

Don’t ask me to source this, but I heard a few years back that the
x-rays of King Tuts gold mask shows that it was made in various
pieces and had to be cast. Now THAT would have been interesting to
see.

Best regards,

Todd Hawkinson
Southeast Technical College
Jewelry Department

At the Progress Tool auction in L.A. a year ago, I bought a 28 in.
long casting arm that will accommodate a 8 1/2 in. long casting
cylinder. Once I make my casting shroud a bit larger, I should be
able to put my “monster” casting arm on my existing Vigor base, and
spin some seriously large castings!

I usually save the vacuum casting for the larger castings that won’t
fit into the centrifical caster, but I like the “theater” of that
molten metal flying around in a circle! High success rate, super
detail.

Jay Whaley

The ancient Indians of North America used clay pots over open
fires to burn out models, then they would take wet vines and tie
them to the pots and then swing them in a circle like pitching a
baseball underhanded to create a centrifugal motion, thus the gold
was "SPUN" into the pot for a casting. 

This is highly unlikely for several reasons, what is your source for
this?

James Binnion
James Binnion Metal Arts