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Small glass project


#1

This is a glass question, but I thought maybe someone would know.

I haven’t worked with glass much but I have a jewelry project that I
need some tiny glass domes for. I was thinking maybe I could slump
them over a mold. It needs to be clear. I have basic glass working
tools – the cutter and the nibbler thingys.

Here are my questions –

  • what kind of glass should I use? (I’m thinking that Crystal Clear
    from is it Bullseye?)

  • what should I make my mold out of? Plaster? Creative Paper Clay?
    What could I make it out of so that it would be reusable?

  • what else should I be asking that I’m not thinking of?

Thanks,

Elaine

Elaine Luther
Metalsmith, Certified PMC Instructor
http://www.CreativeTextureTools.com
Hard to Find Tools for Metal Clay


#2

Here are a few thoughts. If you are going to use the glass with PMC,
use Bullseye 1401.50. Otherwise, you can use Bullseye 1101.50. If you
are going for a dome, and I don’t know whatr size, keep in mind that
when slumping a piece of glass over a mold the corners will fold and
it will be difficult to make a symetrical dome shape.

You could use some fiber board, hollow out the shape you want, and
then melt (cast) the clear glass into the mold shape. Here the
problem is that the edge of the dome touching the fiber board will
not be as smooth as the “free” edge.

I would be happy to continue this discussion on-line. Contact me at
seguinkid@aol.com

Happy New Year


#3

Dear Elaine:

Always use compatible glasses if you’re going to be layering or
piecing. I predominantly use Bullseye. 90 COE or above. COE:
coefficient of expansion. If you’re not going to be layering, don’t
worry about this.

Secondly, I use stainless steel as a mold. To use, you have to heat
the mold to about 150 degrees & then brush the surface w/ kiln wash.
If you don’t heat the mold, the kiln wash won’t adhere to it.

Kiln wash is a powder that you mix: half kiln wash/half water &
stir.

You may have to grind the edges smooth after firing depending on
your outcome. You’ll probably want to fire to between 1500 & 1600
degrees when the glass begins to “slump” or mold.

Please let me know if I can be of further help. I’ve been in
business w/ glass art & jewelry for 10 going on 11 years. One big
problem; you may become addicted! It’s a wonderful media to work w/,
especially when you use dichroic glass…

Regards, Audie Beller of Audie’s Images-


#4

Hi, Elaine,

Slumping glass can be fun, but it is not easy to do with any
precision. You mentioned “tiny domes”. Glass will not slump into
tiny shapes just from its own weight unless you slump a way
oversized piece and cut it down. Even then, it is likely to fold
more than mold. In addition, it will take on the texture of whatever
you mold it onto, so it won’t just be shaped clear glass. The change
in texture can perhaps be avoided if you only slump it slightly, but
domes will require considerable movement/heat/softening.

If you do try this, be sure to ramp the temp down very slowly, maybe
with a “soak” at annealing temp-- I think that’s about 850, but it’s
been a long time… Otherwise, the piece may self-destruct from
stress.

I used to make forms out of bisqued clay, and paint them with
whiting or kiln wash to keep the glass from sticking. These were
reusable.

Thinking about it now, I think if I wanted a dome, I’d start with a
sheet of glass at least three times the width of the dome. I’d cut 2
sheets of metal-- heavy copper would probably work-- oxidation will
prevent the glass sticking to it-- the same size, and cut a hole the
size of the dome in the middle of both sheets. I’d sandwich the
glass in the copper and put it in the kiln up on bricks so there was
space under the hole, and weight the top as well so the glass would
stretch, not slip. Then heat and watch until the glass stretched
down into shape, cool the kiln slightly to stop it, close it down to
cool as slow as possible. Later, cut off the “flange”.

All in all, there must be an easier way.

–Noel


#5

Hi everyone. I am new and this is my first posting. I have been
making jewelry for about 10 years. I read Elaine question about
needing small glass domes. She was thinking about slumping glass to
make them. I have another Idea. I have made several pieces that
needed glass domes, I cut the ends off glass test tubs from a
medical supplies store. They come in all sizes. Its very easy just
wrap the glass tube with masking tape and use a cut off disc with
your flex shaft. I have made all sizes from very tiny to large. I
bezel set mine so there was no need to finish the edges but you
could. (you may break a few but there cheep) hope this helps Betty

God be with you always
Betty


#6

Hi Elaine, how tiny? I may be able to help…but how “tiny” is going
to be very relevant! Check out this link for some of what I do with
glass in collaboration with Joanna Bone…

http://tinyurl.com/djcf8

Kimmyg
@Kim_Griffith


#7

Elaine - Have you considered working with a glassblower? It sounds
like this might fit your needs better than slumping.

kara


#8

Dear Elaine,

A lot depends upon what you mean by “tiny glass domes”.

Easiest approach is to find something pre-made, like a test tube,
and cut it down to size with a glass cutter, and grind or sand the
resulting edge ( there are lots of sizes of test tubes out there).

If you can’t find the right size, consider having someone blow the
forms into a mold. Try pyrex glass, it’s easy to work with. Then cut
and grind.

I’ve been slumping glass for 30 years. Slumping a bowl is easy,
slumping a hemisphere or dome is hard, the circle of glass that
you’ll start with, tends to fold over itself on the vertical wall
during the heating process.

Good Luck!


#9

Depending on the size and other specks of the domes you want, try
looking at scientific glass. You might be able to use something like
a watch glass (there glass domes) or look through the other stuff
they have. Other wise depending on the size you may need to either
get them blown or cast, in that case talk to a glass blower, as one
of my concerns would be whether or not it would need annealing. In
principal it sounds easier to make glass then actually making it.

Zoe Hardisty


#10

Hi all,

Have you considered working with a glassblower? It sounds like this
might fit your needs better than slumping. 

Thanks to everyone for all the terrific suggestions! It has become
clear that slumping is not the way to go. I will try the bit with
test tubes, and if that doesn’t work, I’ll work with a glassblower.

Thanks again,

Elaine

Elaine Luther
Metalsmith, Certified PMC Instructor
http://www.CreativeTextureTools.com
Hard to Find Tools for Metal Clay


#11

G’day;

In about 3 lives ago I used to be a scientific equipment glassblower
and quite often needed to cut glass tubing. The standard method for
lengths of tube or rod is to make a deep scratch with a sharp three
cornered file, apply saliva to the scratch with the finger, and use a
pulling-snapping motion, when it would break cleanly.

To cut a small piece off the dome end of a test tube almost at the
end, one can make a deep scratch then apply the semi molten end of a
piece of narrow glass tube or rod to the scratch. This induces a
crack, and if the crack is followed round the tube with the red hot
glass, it will crack right round. For Pyrex tube one made the usual
scratch then wound wet blotting paper around the tube either side of
the crack, building up a thickness at least half a centimetre, with a
gap of about 4 - 6 millimetres between the strips. A pencil pointed
very hot flame is played on the gap whilst turning the tube, and the
resulting strain crack will run around the tube following the flame.
Rubbing the cut end on a sheet of wetted 200 grit wet-'n-dry abrasive
paper with a circular motion will give you a clean edge.

If you need to cut a glass bottle or jar, the simplest way is to
fill it to a scratch mark with fairly thick motor oil; make an iron
rod orange hot and plunge it into the oil. The glass will crack
perfectly.

Another method is to take a length of heavy fencing wire (about
8SWG) and shape an end so it fits neatly round the bottle with no
gaps. Make the wire red hot and place the bottle in the curve and
turn it slowly. It will crack at the wire-glass junction. Clean up
the edge with wet-'n-dry.

When in the Navy and horribly ill and seasick I once managed to
chuck all the mess cups over the ships’ side with the washing up
water. I scrounged oil off the engineers and bottles off the men and
made a dozen glass cups this way. But I wasn’t popular.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ


#12

Hi Elaine,

Late in getting back to you, but I saw no one had mentioned Edmund
Scientific. http://www.edsci.com/ They have an awesome store down in
New Jersey I remember going to all the time in university days.
Allllll sorts of optics in a zillion different sizes and shapes!

As I am a glass jeweler/blower outside of my job at LID, I would of
course recommend working with a glass artist, but it sounds as if you
need specific sizes and ES is supa awesome!

Cheers and good luck! Let’s see some pictures when you complete your
project! Sounds intriguing!

Kindest Regards,

Kim Fraczek
Creative Director

LID Diamond House
20 West 47th St.
Suite 600
New York, NY 10036


#13

Hi Elaine,

Late in getting back to you, but I saw no one had mentioned Edmund
Scientific. http://www.edsci.com/ They have an awesome store down
in New Jersey I remember going to all the time in university days.
Allllll sorts of optics in a zillion different sizes and shapes! 

similar to Edmund scientific but in Chicago :

http://www.sciplus.com

they have a store in Chicago:

http://www.sciplus.com/storeDetail.cfm?store=1

this is a sister company:

http://www.labwarehouse.com/

jesse


#14

Continue from
https://orchid.ganoksin.com/t/small-glass-project

To cut a small piece off the dome end of a test tube almost at the
end, one can make a deep scratch then apply the semi molten end of
a piece of narrow glass tube or rod to the scratch. This induces a
crack, and if the crack is followed round the tube with the red
hot glass, it will crack right round. For Pyrex tube one made the
usual scratch then wound wet blotting paper around the tube either
side of the crack, building up a thickness at least half a
centimetre, with a gap of about 4 - 6 millimetres between the
strips. A pencil pointed very hot flame is played on the gap whilst
turning the tube, and the resulting strain crack will run around
the tube following the flame. Rubbing the cut end on a sheet of
wetted 200 grit wet-'n-dry abrasive paper with a circular motion
will give you a clean edge. 

Thanks to John and to Orchid. My small glass project is progressing.
Originally I had thoughts of slumping my own domes, but Orchid
suggested cutting down test tubes, which I finally did successfully,
using John Burgess’s instructions below. (amazingly, I had some
blotting paper!)

It was kind of fun too!

Just wanted to say thanks!

Elaine

Elaine Luther
Metalsmith, Certified PMC Instructor
http://www.CreativeTextureTools.com
Hard to Find Tools for Metal Clay