problems with glass beads

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I make glass beads with a torch.
I think i use the wrong wire.
About 30% of them brake later on.
When i melt glass directly on thin copper wire only few are breaking.
I bought it ( the one i use for beads ) from a welding shop and it is
for welding actually.
I dip the wire in kaolin before using it.
should i use copper wire or is steel better?


Re: problems with glass beads
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ARE YOU ANNEALING??

if not - that is your problem.. not the wire.

STEEL  is the best mandrel wire to use.
Kaolin alone is not a good bead release....

sounds like you have multiple problems you need to resolve.





Cheryl
DRAGON BEADS
Flameworked beads and glass
http://www.dragonbeads.com /


Re: problems with glass beads
snipped-for-privacy@aol.combeads (Cheryl) wrote >
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Have you disovered the ISGB message boards yet?
By reading through old posts and asking your questions there you would
be in contact with many experienced and new beadmakers and more
quickly sort out your teething problems with torchwork.

http://www.isgb.org/forum/ubbthreads/ubbthreads.php

Re: problems with glass beads


Elizabeth in UK wrote:
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Thanks. I will look in to it.


Re: problems with glass beads


Cheryl wrote:
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If this means if i have a place were i let the beads slowly cool down ...
I let them cool down at room temperature.
I would need a annealing oven then.
I only have a small enamel oven.
What temperature would be ok?


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Re: problems with glass beads
You don't need an annealing oven as far as I know for normal sized
beads. An annealing oven is required for larger pieces such as blown
glass so that the temperature gradientand therefore stress  in the glass
is kept to a minimum. My mate who does some bead making just has a pot
with an insulating media in it. I am not sure what it is, maybe
vermiculite?. The bead once done is placed in the insulating media which
slows the cooling to room temperature considerably compared to cooling
in air.

oregano wrote:

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Re: problems with glass beads
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Sand is often used commercially. The glass has to be below its softening
point before it goes in, though. We used to anneal marbles (made at about
240/min) by dropping them into 45-gallon oil drums and letting them cool
down naturally when full. The runway and elevator from the marble machines
had to be long enough to let the marbles cool down below the softening point
before they entered the drums, otherwise they stuck together. The annealing
was better than that obtained in a lehr.
--
Terry Harper
http://www.terry.harper.btinternet.co.uk /


Re: problems with glass beads
  "Normal sized"
  That depends on how small "normal" is, whether it has been flame annealed,
and how well insulated you keep it.
  The biggest variable will be the thickness of the walls - thick walls
require more annealing time.  Big pieces that are blown thin will survive
better than thick small pieces.
  If the marble is about 1/2" across, with a rather large mandrel, the wall
thickness may be only 3/16".
  When a bead is more like an inch, the wall thickness may be nearly 1/2"
and there will be much more glass as it will probably be longer.
   At some size, all beads should be annealed, not just soaked in
vermiculite.  Learning to do it early will save that first best big bead
that otherwise might be lost, the effort wasted.

--
Mike Firth
   Hot Glass Bits Furnace Working Website
We've slightly trimmed the long signature. Click to see the full one.
Re: problems with glass beads
My mate who does some bead making just has a pot
with an insulating media in it. I am not sure what it is, maybe
vermiculite?. The bead once done is placed in the insulating media which
slows the cooling to room temperature considerably compared to cooling
in air.>

yeah - they do that in INDIA and CHINA too -- guess what -
those beads ARE NOT ANNEALED.

guess what - they are FAMOUS for BREAKAGE

"slow cooling" is NOT NOT NOT  annealing...  there is NO SUBSTITUTE for
annealing...


Cheryl
DRAGON BEADS
Flameworked beads and glass
http://www.dragonbeads.com /


Re: problems with glass beads
I would need a annealing oven then.
I only have a small enamel oven.
What temperature would be ok?>

I use an old converted enamel oven
but you must be able to CONTROL THE TEMPERATURE And THE TIME OF COOLING.

sounds to me like all your beads are breaking because you are NOT annealing-
it isn't your mandrels ...
you HAVE to anneal...

Cheryl
DRAGON BEADS
Flameworked beads and glass
http://www.dragonbeads.com /


Re: problems with glass beads
oregano wrote:
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How do you hold on to a copper wire that is in a flame? Ouch.
--
Jack


    http://photos.yahoo.com/bc/xmissionbobo /

Re: problems with glass beads
The problem is the copper wire.  Of all the metals
that you might use, copper is not going to work
well with glass.  Glass must be annealed by bringing the temperature down
SLOWLY.  Copper
is not annealed by this type of handling.  It must
be quenched QUICKLY from cherry red to cold.
That anneals the copper and makes it soft and
ductile. Cooling copper slowly will make it very
brittle.  That is why your copper wire breaks.
Hal
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Re: problems with glass beads
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I don't think that he was saying that the copper wire was breaking. I think
it was the glass beads that were breaking.

You are right in that the glass needs to cool slowly to prevent the build up
of stresses that will fracture it later.

You are a little off on the behavior of the copper wire.

Metals have basicly two states, hardened and annealed. All metals can be
hardened to some degree and all can be annealed. Hardening typically happens
one of two ways. The first is work hardening, where through mechanical
stresses (bending, hammering, twisting, forming, etc) grains are pushed and
wedged into each other and the metal gets harder. The increase in hardness
is caused by the internal stresses in the metal itself. Over work the metal
and it will fracture. The second method only works with iron (and a few
others) based alloys that undergo a phase transformation at elevated
temperatures. Steel for example, changes from one crystal structure to
another a certain temperature. If you quench the steel you can freeze the
crystal structure in a form that isn't supposed to exist at room
temperature. The resuting stresses in the material make it harder. Curiously
enough, some steel alloys can also spontaneously crack if they are fully
hardened and not annealed after (just like glass).

If you take this hardened piece of steel and heat it back up to the
transition temperature, some of the crystals start to revert back to the
lower temperature form and the material looses some hardness, but gains
ductility. This makes the material tougher, but I digress.

This same heating technique will anneal any metal. Work hardening stresses
the grains by breaking them up and wedging them together, heating causes the
grains to grow and relieve the internal stresses. If there is no phase
change (Copper does not have one) the material can only be work hardened.
Heating the metal up to its annealing temperature will anneal it and then it
doesn't matter how fast you cool it, it is still annealed.

If the copper is breaking in this case, it is probably due to either
oxidation or it is alloying with something in the coating or glass and
getting intergranular corrosion.

If he got the copper from a welding store, then it probably isn't copper. It
is probably copper clad steel. They usually don't weld with copper.

-- Joe

--
Joseph M. Krzeszewski             Mechanical Engineering and stuff
snipped-for-privacy@wpi.edu                Jack of All Trades, Master of None... Yet


Re: problems with glass beads
I supplied a number of 1/16" 316 stainless steel welding rods to a
friend for his bead making and he has had no problems with these. This
was much cheaper than him buying the stainless  ones from the normal
supplier.

oregano wrote:

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Re: problems with glass beads


David Billington wrote:
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I make the beads under flame and then let them cool down at room
temperature.
I guess they cool down to quickly and brake then.

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