SLUMPING.

Hello,
I'm a raw beginner with experience so far only of glass painting and the
industrial cutting and edgeworking to profile (underwater) of thin LcD type
glass.

I've collected a great deal of cullet of various colours from bright blue
through amber to deep amethyst, and want to slump a largeish (1 metre by 50
cm) glass panel from them.
My intention is to lay the various colours of cullet which I've broken into
tiny fragments on a sheet of 3mm tinfloat (tin side down) with the various
lands of colour separated by long narrow strips of .5 mm LcD glass (which I
have). The desired depth of the piece, which is intended to have an
interesting rough and knobbly surface, is approximately 10 mm.

At a relative's house I have firebricks and several large iron plates from
which I can construct a flat oven. There are also a large number of (mainly
oak) logs, the intended fuel.

Questions; how do I stop the softened cullet from sticking to the backplate?
A few little tests I've done with small quantities all stuck to the plate,
or picked up so much carbon as to be ruined.

How much time should I allow for the cooling cycle? If sand were heaped
over the kiln at the end of the firing period, would that slow the cooling
enough to prevent the panel from remaining brittle?

Are logs, (even hardwood logs) likely to generate the required heat?
I'm not after a full melt; I'm merely trying to get the cullet to coalesce,
lose it's sharp edges and stick together.

I did Google for all this info, but there are so many irrelevant pages with
similar titles (but no info) that this posting seemed the only way to find
out.

Thank you,

Designori.

"Des" wrote in message
...
Hello,
I'm a raw beginner with experience so far only of glass painting and the
industrial cutting and edgeworking to profile (underwater) of thin LcD
type
glass.

I've collected a great deal of cullet of various colours from bright blue
through amber to deep amethyst, and want to slump a largeish (1 metre by
50
cm) glass panel from them.
My intention is to lay the various colours of cullet which I've broken
into
tiny fragments on a sheet of 3mm tinfloat (tin side down) with the various
lands of colour separated by long narrow strips of .5 mm LcD glass (which
I
have). The desired depth of the piece, which is intended to have an
interesting rough and knobbly surface, is approximately 10 mm.

At a relative's house I have firebricks and several large iron plates
from
which I can construct a flat oven. There are also a large number of
(mainly
oak) logs, the intended fuel.

Questions; how do I stop the softened cullet from sticking to the
backplate?
A few little tests I've done with small quantities all stuck to the plate,
or picked up so much carbon as to be ruined.

How much time should I allow for the cooling cycle? If sand were heaped
over the kiln at the end of the firing period, would that slow the cooling
enough to prevent the panel from remaining brittle?

Are logs, (even hardwood logs) likely to generate the required heat?
I'm not after a full melt; I'm merely trying to get the cullet to
coalesce,
lose it's sharp edges and stick together.

I did Google for all this info, but there are so many irrelevant pages
with
similar titles (but no info) that this posting seemed the only way to find
out.

Thank you,

Designori.



Handle the problems one step at a time.

Points being .....glass sticking to mold and mold carbon. Use Stainless
steel as a mold and Boron Nitride (Google... zyp products) as a mold
separator to prevent sticking. If you use carbon steel, you will have the
carbon problem.

To use Wood to fire the kiln, you will also need a forced air addition to
get the temperature, which will also make the fire wood burn faster, so you
will use more fuel(wood) than estimated. In India, coal is regularly used
to heat a glass furnace, but forced air is also used to get up to temp.
This is theory on my part, never tried to re-invent the wheel, Natural gas
always seemed to be there...I used that.

How much time should I allow for the cooling cycle? You will probably not
be able to hold the temp in an annealing range so the shotgun method will do
the trick, you can't over anneal it, so once you hit fuse temp, and start
down, remove the heat source(and insulate it somehow , if that means sand,
then pile it on thick to keep the loss of heat to a minimum, let it come
down 1 1/2 deg per min on thin pieces that should work. You are going to
have to test fire a few so you know what your kiln will do and how it acts.

Reports of actual results would be appreciated.

Use a kiln wash to keep from sticking (available commercially from Bullseye,
Hotline) pretty inexpensive. Biggest problem is that the different types of
glass you are using will have different COE (coefficient of expansion) and
may cause the piece to crack form the stress caused by each type cooling at
different rates. I have no experience with the fuel you mention, Bullseye
offers annealing charts regarding cooling schedules and also offers
recommended temps to fire to.good luck! m
"Des" wrote in message
...
Hello,
I'm a raw beginner with experience so far only of glass painting and the
industrial cutting and edgeworking to profile (underwater) of thin LcD
type
glass.

I've collected a great deal of cullet of various colours from bright blue
through amber to deep amethyst, and want to slump a largeish (1 metre by
50
cm) glass panel from them.
My intention is to lay the various colours of cullet which I've broken
into
tiny fragments on a sheet of 3mm tinfloat (tin side down) with the various
lands of colour separated by long narrow strips of .5 mm LcD glass (which
I
have). The desired depth of the piece, which is intended to have an
interesting rough and knobbly surface, is approximately 10 mm.

At a relative's house I have firebricks and several large iron plates
from
which I can construct a flat oven. There are also a large number of
(mainly
oak) logs, the intended fuel.

Questions; how do I stop the softened cullet from sticking to the
backplate?
A few little tests I've done with small quantities all stuck to the plate,
or picked up so much carbon as to be ruined.

How much time should I allow for the cooling cycle? If sand were heaped
over the kiln at the end of the firing period, would that slow the cooling
enough to prevent the panel from remaining brittle?

Are logs, (even hardwood logs) likely to generate the required heat?
I'm not after a full melt; I'm merely trying to get the cullet to
coalesce,
lose it's sharp edges and stick together.

I did Google for all this info, but there are so many irrelevant pages
with
similar titles (but no info) that this posting seemed the only way to find
out.

Thank you,

Designori.

Des wrote:

Hello,
I'm a raw beginner with experience so far only of glass painting and the
industrial cutting and edgeworking to profile (underwater) of thin LcD type
glass.

I've collected a great deal of cullet of various colours from bright blue
through amber to deep amethyst, and want to slump a largeish (1 metre by 50
cm) glass panel from them.
My intention is to lay the various colours of cullet which I've broken into
tiny fragments on a sheet of 3mm tinfloat (tin side down) with the various
lands of colour separated by long narrow strips of .5 mm LcD glass (which I
have). The desired depth of the piece, which is intended to have an
interesting rough and knobbly surface, is approximately 10 mm.


I have to ask. Is there some reason you believe that the glasses you are
attempting to melt together have any chance of staying together? I don't
recognize the LcD term, but you mention float. Are the cullet and float
compatible?

Not really trying to be a smart ass here but if you're trying to mix
random glasses together and heat them by burning oak (if you knew the
process of getting enough heat from burning wood, you wouldn't have had
to ask that question)and end up with a piece 1 x 1/2 Metre (who knows
how thick it is, the most important factor) I don't give you much of a
chance. It would be something like me hanging out on a board that
discusses space travel hoping to put something into orbit soon.

Keep us posted.


--
Jack

Plonked by Native American

bobo1148atxmissiondotcom


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

"nJb" wrote in message
...
Des wrote:

Hello,
I'm a raw beginner with experience so far only of glass painting and the
industrial cutting and edgeworking to profile (underwater) of thin LcD
type
glass.

I've collected a great deal of cullet of various colours from bright
blue
through amber to deep amethyst, and want to slump a largeish (1 metre by
50
cm) glass panel from them.
My intention is to lay the various colours of cullet which I've broken
into
tiny fragments on a sheet of 3mm tinfloat (tin side down) with the
various
lands of colour separated by long narrow strips of .5 mm LcD glass
(which I
have). The desired depth of the piece, which is intended to have an
interesting rough and knobbly surface, is approximately 10 mm.


I have to ask. Is there some reason you believe that the glasses you are
attempting to melt together have any chance of staying together? I don't
recognize the LcD term, but you mention float. Are the cullet and float
compatible?

Not really trying to be a smart ass here but if you're trying to mix
random glasses together and heat them by burning oak (if you knew the
process of getting enough heat from burning wood, you wouldn't have had
to ask that question)and end up with a piece 1 x 1/2 Metre (who knows
how thick it is, the most important factor) I don't give you much of a
chance. It would be something like me hanging out on a board that
discusses space travel hoping to put something into orbit soon.

Keep us posted.
Jack

Thanks Jack; thinking about it, tackling a piece that big as a first project
does seem rather unwise. I simply don't have any pieces of stainless steel
that big either. I do have 50cm square pieces. Stainless steel is a pig to
work with.

My other half just suggested that I might avoid the variation in the
expansion of the glasses by firing the individual parts separately to keep
the jobs small, then wiring or framing it together.
She also suggested that I could avoid the melting process altogether by
embedding my cullet in acrylic resin. Well, that wouldn't allow the colours
to spread like I wanted them to, and it wouldn't be as permanent a job.By
the way, I did mention the desired thickness in my post; I've settled on
10mm.
I do have access to no end of calor gas; it just struck me that the logs
were there and might be a convenient heat source. I wasn't aware of the fact
that they aren't quite enough on their own.
H'mmm.

Time to stop thinking and do. I'll draw up my moulds for the feature pieces
tomorrow (a big 120mm dia orange sun and green and amber leaves mainly) and
send for some kilnwash.
This sure as hell beats television!

Thanks,

Des.

Des wrote:


Thanks Jack; thinking about it, tackling a piece that big as a first project
does seem rather unwise. I simply don't have any pieces of stainless steel
that big either. I do have 50cm square pieces. Stainless steel is a pig to
work with.

Can you get shelf paper where you're at? Ceramic blanket? That would
solve the sticking problem for sure.

My other half just suggested that I might avoid the variation in the
expansion of the glasses by firing the individual parts separately to keep
the jobs small, then wiring or framing it together.

You don't mention what type of cullet you're using. If it's something
made for casting you might be in good shape but may have trouble
matching it to the float and the other stuff you're using for strips.

She also suggested that I could avoid the melting process altogether by
embedding my cullet in acrylic resin. Well, that wouldn't allow the colours
to spread like I wanted them to, and it wouldn't be as permanent a job.By
the way, I did mention the desired thickness in my post; I've settled on
10mm.


Yes you did. My mistake.

I do have access to no end of calor gas; it just struck me that the logs
were there and might be a convenient heat source. I wasn't aware of the fact
that they aren't quite enough on their own.
H'mmm.

Yes, the wood would need an induced draft to attain and control the
heat. Where are you? Isn't there an electric kiln you can use. They
seem to work best for glass. Efficient and controllable.

Time to stop thinking and do. I'll draw up my moulds for the feature pieces
tomorrow (a big 120mm dia orange sun and green and amber leaves mainly) and
send for some kilnwash.

You would be happy with the ceramic fiber. If the pieces have flat
surfaces you wouldn't even need molds. You can fashion the outside walls
from 1/16 or 1/8 inch fiber.

This sure as hell beats television!

Not if there's NHL hockey on.


Suggested reading:

http://www.warmglass.com/phpBB/index.php

The searchable archives are great.

Here's a great tutorial:

http://www.warmglass.com/basic.htm


Good luck. Keep us posted.
--
Jack

Plonked by Native American

bobo1148atxmissiondotcom


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