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Casting story


#1

So, this lady I know - right over there, in fact - had some casting
to do just now. She cast three flasks for a goldsmith we do work for,
and then she put a silver casting in the centrifuge that’s for
herself.

Flask goes in the cradle & position gets checked, crucible goes in
the crucible place, silver goes in the crucible, torch gets lit,
metal is melted and the pin drops and she lets it fly and…

Silver goes flying everywhere but of course we have a shield. Lady
says, “I need to check that arm because it’s been acting up”. I say
maybe the weight was wrong and we’ll know when it stops. Crucible
stops.

Dodo brain had put the flask in backwards…She put it in,
wanted to change the crucible cradle and in the process she turned it
around and put the thing in with the sprue on the wrong end…
Funny, but we all need to pay attention… And the flask is still
castable, there’s just a little black spot on one end ;} Written with
permission, BTW.

Happy Thursday in SF,
John
http://www.donivanandmaggiora.com


#2

You are playing with fire here, John, I hope you FOR
SURE had permission from your other half!!!

John Dach


#3

Good to remind us we cal all be dodos over something! And safety is
an issue in so many things we do. Be safe people - you are all
precious beings!

Barbara


#4

Oh man, that is funny!

I have a goldsmith friend who came over to see if he could buy a few
stones from me. I asked him what he was making. He said he had to
remake a ring that he had damaged. When I asked for more detail he
confessed that he had been working very late to try to repair a ring
while waiting for the kiln to get to casting temperature. The ring
had rubies and diamonds in it. He got up to cast his flask and when
he got back to his bench he could not find the ring he had been
working on. He searched and searched his shop, but couldn’t find it.
Then he walked over and looked in the crucible of his casting machine
and there he saw the rubies and diamonds from the ring stuck in the
flux of the crucible (some of them anyway, the rest were in the
casting). Sometimes it’s better to just go home and go to sleep.


#5

Once, in one of my firsts solo vaccum castings, just after pouring
the metal I’d simply grab the flask with the tongues and turned over,
no reason at all, just did it, the amazing thing was the main sprue
metal got out over a pan but the more that 30 pieces were cast.

Gustavo


#6

Another great casting story, mind-boggling accident.

A wax-setter spent a whole week+ setting diamonds into the wax
forms, treeing the multitude of flasks. At least 75-100 carats of
mini-clusters, the inventory of 10kt.-14kt…about 2,000 rings.

Apparently the caster also had flasks of plain rings as well.

He forgot to mark in the investment where the diamonds were located.
He did his regular casting, after the spinning he then immediately
dropped the crucible into very cold water, and then left to cool.

He also did this to each of the crucibles with wax-set diamonds.

Not knowing his ultimate error of dropping hot gold with I1-2
diamonds is a definite “no-no!”… or a big “woops!”

A deluge of profanity emerged from that casting room. The room
turned “blue” from those ensuing language that reached the room where
the plant mgr. was sitting. The wax-setter turned an absolute white
from his week long labours being wasted. The caster still had his
job, but after this ordeal, he felt like . BTW, all of the diamonds
were destroyed!

Moral of this story; mark your ‘investment’ if there are any stones
being wax-set… Gerry!


#7

Years and years ago (just after the 2nd World War) my mom was a
dental technician in Solingen, Germany. She told stories about
spending hours and hours on the lab floor on hands and knees with
tweezers picking up little droplets of gold from a casting gone
wrong.

Cheers all
Hans Durstling
Moncton, Canada


#8

Hi John,

I can see that happening. I like to use those types of mishaps to get
some very interesting textured metals. I hold on to them and end up
creating some really cool pieces. I don’t recommend doing it on
purpose, but when given lemons make lemonade. When given limes make
margaritas. Best wishes to all,

Ken Moore
www.kenworx.com


#9

Wow, never done that before. I’ve thrown metal about for having wrong
weight of crucible versus counterweight, clockwork spring breaking
and jamming, flask moving out of alignment on cradle, metal punching
hole through too thin investment base and even crucible hole becoming
blocked.

The closest I have had to a disaster is my clothing catching fire by
standing too close to a radio frequency furnace whilst making an
experimental single crystal nickel turbine blade. There is NO
radiant heat but the RF leakage at this particular point was focussed
on my lab coat worn underneath foundry leathers. It just started
smouldering and then flames appeared. We also used to melt and cast
platinum and YBCO (superconductor material) but never got to make
single crystal Cubic Zirconia. We could also melt alumina if the
alumina tubing the metals were encased in werent centred, packed and
cooled correctly. To my mind a lot more fun than playing with the big
lasers but I doubt if a James Bond villain will ever have one.

Nick Royall


#10

Amazing how reading all the amusing stories brings back a memory!!!
While teaching Lost Wax Casting at one particular time, after
removing the casting of hand carved wax bears from the dissolved
investment, found that I had not used the correct amount of silver
for the weight of the wax. There were four lovely “buttless” bears!

But, being the creative person I am!!!, ha, I have made three of
them into treasures! I expoxied turquoise pieces to the rump of each
one, and shaped on the lapidary wheels and created very interesting
Turquoise Bears. My brother wore one of them to the day he died…I
sold one of them to a former student, and will keep the third as a
reminder of the interesting disaster. I have the 4th one to show to
students how important the silver measure is before casting!

Had not thought of this for years.

Also, in teaching PMC and having students think up ways to
incorporate found objects into the creation, one lady brought a
recovered bar of diamonds to add to a pendant. At that time, I didn’t
realize that diamonds are carbon! Result: The bar was still there
after the required time in the Kiln for the PMC items. We looked
forever in the bowl of vermiculite for the little diamonds. Needless
to say they were burned up in the process. They were fortunately very
small stones and she accepted the incident without malice!!!

I still don’t know if I would try casting a diamond with the wax as
was just told, but surely not at the temp for PMC!

Thanks for all the humor.
Rose Marie Christison


#11

I’ve got one from many years ago.

I decided to try investment casting for the first time.

I didn’t have a centrifugal machine, so I made a heavy duty sling
caster. It was really solid, and I’d figured out an effective
cradle… or so I thought.

It was about 500g of 80/20 a nice white bell metal.

I had an old enameling kiln, so I ran that for a short burn out
cycle (I’d previously had the flask in the oven melting the wax out).
At the 2 hour mark I had a perfect burn out, at which time the
electric element in the kiln expired. “Meh”, I thought. “These things
happen, a new wire wont cost me much”.

The melt was ready, on time, only takes 8 minutes for 500g. The
flask was placed into the cradle (but I didn’t do it securely).

Got up the gumption and spun the sling caster, after the third
swing, the flask came loose and sped in a straight line diagonally
across my back yard, depositing granules of 80/20 as it went. I felt
like a prospector picking up those granules.

Funnily enough the casting was a success.

However bell metal is brittle and melodious, but that’s another
story :wink:

Regards Charles A.


#12
Good to remind us we cal all be dodos over something! And safety
is an issue in so many things we do. Be safe people - you are all
precious beings! 

Unfortunately the worst story I ever heard was a friend taught night
classes to adults at a high school. A woman was so excited about
what she cast she picked up the flask while hot to show what she had
done. Major burns, fused skin.

Richard Hart G.G.
Denver, Co.


#13
she picked up the flask while hot to show what she had done. Major
burns, fused skin. 

I did something like that once. I was welding bronze sculpture and
did not secure it properly. When I got red hot, something shifted
and it started falling. When bronze hot it is as fragile as glass.
Without thinking I grabbed it with my left hand to right it up. My
boss was welding next to me. He realized what happened before I did.
We always had liquid vitamin E in the shop. He started to pour it all
over my hand. I was back to work next day, without even a blister.
Vitamin E is the best remedy against burns and minor cuts.

Leonid Surpin
www.studioarete.com


#14

Greetings:

Thanks for sharing your casting tragedies. I feel much less alone.

I cast hollow creatures with tiny holes for the investment to
escape. Usually it’s a rabbit or frog with a holes for the nose and
a hole at the bottom or at the side of the tail. I can’t tell you
the number of times that the creature miscast with a big hole in the
side. At least I mostly cast in bronze or shibuichi, and failures
are not expensive.

I foundthat putting a wire through the nostril holes or better yet a
wire on the x axis and one on the y axis increases my chance of a
successful cast. My theory is that heavy molten metal slams against
a small column of plasterin the air holes of the nostrils. This
breaks the plaster supporting the piece and causes a miscast.
Putting in wires stabilizes the investment in the middle of the
piece and allows for a successful cast.

Sally Parker


#15
Vitamin E is the best remedy against burns and minor cuts. 

It didn’t hurt either, that he essentially was soaking your burn in
a cooling, hydrating, water solution almost instantly after the burn
occured. That greatly reduces the injury.

Peter


#16

Sally,

My guess is that most of us who cast hollow items ran into the same
problem of having big holes in our cast pieces when we first started
casting.

You are correct in saying the investment breaks free of the very
small sections of investment that are holding the core through the
nose and eyes holes. The core of investment breaks loose and floats
on the molten silver in the hollow of the investment and presses
against the outside of the mold. That causes the hole in the casting.

It is a very common practice when casting hollow items from jewelry
to large sculptures to run rods from the outside of the item into
the core of the item. The rods will act as re-bars and prevent the
core from moving.

I cast small hollow pieces of pottery. I place a rod of silver that
extends from the outside to the inside of the pottery. Some times I
run a silver wire from the outside to the inside of the item through
a hole in the wax.

You can see a drawing of the core floating in a casting and a photo
of my solution on the following blog:

http://www.ganoksin.com/gnkurl/1zh

Be sure you check out my anti fire scale vacuum casting procedure.
It’s a very simple way to prevent fire scale on vacuum cast items.


Good luck,
Lee Epperson


#17
I did something like that once. I was welding bronze sculpture and
did not secure it properly. When I got red hot, something shifted
and it started falling. When bronze hot it is as fragile as glass.
Without thinking I grabbed it with my left hand to right it up. 

That’s a lucky escape.

Just curious, was that bronze Everdur? I use 90/10, and it’s pretty
user friendly, and is a lot more robust.

Regards Charles A.


#18

Hi Sally,

I have a video on this computer someplace going through the process
of making an aquamanilia vessel, I can hunt it down if you are
interested.

Regards Charles A.


#19

Not a casting story, more of a feeling stupid story.

I had a goldsmith friend stop over one morning to visit and ask if I
had a small stone he needed for a job. I did, after the visit he took
it and left. Later that afternoon he was back asking if I had another
one just like the one he took that morning. I asked him if he’d
broken the first one, he said no, that after he got back to his shop
he was looking at the stone, then remembered he needed to take his
vitamins, he took them and then couldn’t find the stone. Down the
hatch it went! He said he didn’t have the time or interest to wait to
try to “recover” the first stone…so he bought a replacement.

Mark


#20
Just curious, was that bronze Everdur? I use 90/10, and it's
pretty user friendly, and is a lot more robust. 

Can’t say. It was new business, and we experimented a lot. We cooked
our own with recipe changing daily.

Leonid Surpin
www.studioarete.com