Fused Glass with Shiny Copper
Glenn Woolum
getting started with fused glass. I live in the Hyde Park, NY area, I've had
several classes with Hot Glass Horizons 2000 in Corning, and I'm working in
hot glass since then.
I've been lurking on this NG for awhile and I'm very impressed with the
knowlegeable responses and posts here.
My question is: Is it possible to preserve the shine of copper foil when
used as an inclusion in fused glass? Every time I include copper foil or
wire in glass, it comes out dark red or sort of blackened in color. Is there
a chemical coating that can be applied to preserve the coppery shine?
The reason I suspect this is possible is because during class, one of the
student's pieces that had copper foil inclusions came out with mottled areas
of shiny copper mixed with areas of the usual reddish/blackish areas. There
must be some kind of physics going on there, but the student had no idea why
that particular piece turned out that way.
-Glenn Woolum
The Crafty Owl
copper has to get sealed in, with no air bubbles, while the temperature
is still fairly low. So if you put down the thin copper onto glass, then
a sheet of thin glass, and take it far enough for the top glass to fuse
with the bottom, you can then use that sandwich in other things, and
take the temp higher. I've only used VERY thin copper, basically leaf.
Hope that works for you.
___
<*,*>
{'-'} The Crafty Owl
-"-"-
Glenn Woolum
--
Regards,
Glenn Woolum
"The Crafty Owl" <craf...@kenelise.demon.co.uk> wrote in message
news:Gqfy5dAK...@kenelise.demon.co.uk...
Barbara Cashman
the copper color to stay in the glass when I was firing in the stationary
kilns. It always burned out. The production kiln, however, got it every
time. I recommend as fast a fire as possible--rather than slow. You need
to seal that edge as quickly as you can to seal the copper. In any case, I
suggest you do it both ways and see what works for you.
Barbara
www.glastile.com
"Glenn Woolum" <gwooly-...@earthlink.net> wrote in message
news:o1DW4.25679$T41.5...@newsread1.prod.itd.earthlink.net...
Gary
production kiln... I have no idea.....thanks
Gary
"Barbara Cashman" <bjca...@mindspring.com> wrote in message
news:8gf1s1$phf$1...@slb0.atl.mindspring.net...
Bert
with kilns for that matter) I don't know how feasible and/or effective
it might be. The idea is to rig a gas nozzle in such a way as to keep
the kiln chamber filled with an inert gas from the time you start
firing until the glass has completely fused around the copper. This
should prevent the copper from oxidizing and changing colors -- it's
the same basic concept as inert gas welding. I don't know how well
sealed a typical kiln is, so I have no idea how much gas would be
required. Just a thought...
Bert
"Barbara Cashman" <bjca...@mindspring.com> wrote:
>I'll have to give you another opinion on this. Tried for 10 years to get
>the copper color to stay in the glass when I was firing in the stationary
>kilns. It always burned out. The production kiln, however, got it every
>time. I recommend as fast a fire as possible--rather than slow. You need
>to seal that edge as quickly as you can to seal the copper. In any case, I
>suggest you do it both ways and see what works for you.
>
>Barbara
>www.glastile.com
>
Bert Weiss
How dare you use my name. It is a good thing this is a newsgroup, because
if I were in your presence I'd have to kill you.
Kilns can not possibly tight enough to achieve what you propose. In order
to exit the element from the kiln there must be plenty of air available for
the element wire to cool, otherwise it disintegrates. That is not to mention
that there must be a way for gasses and moisture to escape if one is firing
enamels or overglazes.
Glenn Woolum
the results...
--
Regards,
Glenn Woolum
"Barbara Cashman" <bjca...@mindspring.com> wrote in message
news:8gf1s1$phf$1...@slb0.atl.mindspring.net...
> I'll have to give you another opinion on this. Tried for 10 years to get
> the copper color to stay in the glass when I was firing in the stationary
> kilns. It always burned out. The production kiln, however, got it every
> time. I recommend as fast a fire as possible--rather than slow. You need
> to seal that edge as quickly as you can to seal the copper. In any case,
I
> suggest you do it both ways and see what works for you.
>
> Barbara
> www.glastile.com
>
>
>
> "Glenn Woolum" <gwooly-...@earthlink.net> wrote in message
> news:o1DW4.25679$T41.5...@newsread1.prod.itd.earthlink.net...
> > Thanks for the suggestion. I'll definately give it a try.
> >
> > --
> >
> > Regards,
> > Glenn Woolum
> >
Glenn Woolum
the peephole would displace enough oxygen to prevent the oxidation (I'm
making the assumption that oxygen is the culprit). It would probably be best
to use a gas that is heavier than air so it wouldn't float up out of the
kiln. What gas would suggest Bert?
--
Regards,
Glenn Woolum
"Bert" <no_...@thank.you> wrote in message
news:5g1niss7augbust4c...@4ax.com...
> I have an idea, but since I have no experience working with glass (or
> with kilns for that matter) I don't know how feasible and/or effective
> it might be. The idea is to rig a gas nozzle in such a way as to keep
> the kiln chamber filled with an inert gas from the time you start
> firing until the glass has completely fused around the copper. This
> should prevent the copper from oxidizing and changing colors -- it's
> the same basic concept as inert gas welding. I don't know how well
> sealed a typical kiln is, so I have no idea how much gas would be
> required. Just a thought...
>
> Bert
>
> "Barbara Cashman" <bjca...@mindspring.com> wrote:
>
> >I'll have to give you another opinion on this. Tried for 10 years to get
> >the copper color to stay in the glass when I was firing in the stationary
> >kilns. It always burned out. The production kiln, however, got it every
> >time. I recommend as fast a fire as possible--rather than slow. You
need
> >to seal that edge as quickly as you can to seal the copper. In any case,
I
> >suggest you do it both ways and see what works for you.
> >
> >Barbara
> >www.glastile.com
> >
Tom White
The physics going on to keep copper bright in fused glass is the physics
of oxidation-reduction. If the copper is heated in a normal air
atmosphere it reacts with the oxygen present and darkens. I suspect
that the student's piece which had areas of bright copper in the dark
areas had some organic contamination on the surface where the bright
areas occured, perhaps traces of adhesive used to hold the copper in
place. If the outer edge of the glass layers seal from heat before all
organic matter is burned off (oxidized) that organic matter seeks oxygen
from any source it can and takes it from the copper oxide, in return
brightening the copper when it reduces copper oxide back to bright
metalic copper. I have had almost complete success keeping copper bright
by painting it with Unique Glass Colors clear before layering it for
fusing. The reason I say what I did above about sealing the edges of
the glass is that I have fired copper on top of the glass with the clear
color on it and it oxidized to the dark color to my disappointment.
This reinforced my theory of oxidation-reduction happening in the closed
system after the edges of the glass seals off. I first noticed the
odidation-reduction effect when I had bright areas of copper on the back
of copper where I had used Elmers glue as adhesive to hold it in place
and the area with adhesive on it turned bright while the rest of the
copper, both front and back, oxidized to the dark ruddy red color. If
anyone on the group would like to see pictures of my work with bright
and ruddy copper in it please email me at the above address. I don't
have a website but will email pictures directly.
Best wishes,
Tom in Texas
Glenn Woolum wrote:
>
> Hi all. I'd like to introduce myself. My name is Glenn Woolum and I'm
> getting started with fused glass. I live in the Hyde Park, NY area, I've had
> several classes with Hot Glass Horizons 2000 in Corning, and I'm working in
> hot glass since then.
>
> I've been lurking on this NG for awhile and I'm very impressed with the
> knowlegeable responses and posts here.
>
> My question is: Is it possible to preserve the shine of copper foil when
> used as an inclusion in fused glass? <snip>
Sundog
Bert __ I dunno' Bert, I think Bert may be onto something here. [?] How
about a steady flow of Argon or such, the inert stuff welders use. Perhaps
it could be introduced at around 900 and stopped once the glass has sealed
the copper at say 1300-1400, then venting resumed. I doubt if a perfect seal
and absolutely oxygen free environment is even needed to get a big reduction
in the oxidation problem [ problem? I like the maroon color myself] You
could run the kiln at full throttle in that range for a minimum time at
fusing temp. They make vacuum chamber kilns so why not this idea? My
curiosity is piqued. Someone else try it and let me know .... heh heh heh..
I tried copper foil tape inclusions in a 20" platter once, and ended up with
garbage.... not just maroon which would have been fine.The gum adhesive
burning off created some nasty bubbles. It was another idea that almost
worked. I have used non-gummed copper foil with success, fully intending the
maroon color change it makes.
[If someone starts posting with my name, Houston, we have a problem]....;-)
regards, Jacques Bordeleau
_________________________________________________________
Bert Weiss wrote in message ...
>Bert
>
>How dare you use my name. It is a good thing this is a newsgroup, because
>if I were in your presence I'd have to kill you.
>
>Kilns can not possibly tight enough to achieve what you propose. In order
>to exit the element from the kiln there must be plenty of air available for
>the element wire to cool, otherwise it disintegrates. That is not to
mention
>that there must be a way for gasses and moisture to escape if one is firing
>enamels or overglazes.
>
>PS http://www,bertisevil.com
>
>> From: Bert <no_...@thank.you>
>> Organization: MindSpring Enterprises
>> Reply-To: no_...@thank.you
>> Newsgroups: rec.crafts.glass
>> Date: Wed, 24 May 2000 02:52:51 -0500
>> Subject: Re: Fused Glass with Shiny Copper
>>
The Crafty Owl
<bjca...@mindspring.com> writes
> The production kiln, however, got it every
>time. I recommend as fast a fire as possible--rather than slow.
Yes, I did mean a fast fire - just that the seal must happen quickly, at
low temp - if the glass takes time to slump, because there's a big gap
or the ramp is slow, the copper doesn't get sealed in early enough. I
use a tiny Paragon Quickfire.
Bert
terms of a constant flow of gas into the kiln. The relative
airtightness (is that a word?) or leakiness of a kiln would determine
the flow rate required. This, combined with the time needed to reach
the fusing temperature, would determine the amount and, more
importantly, the cost of the gas -- it may not be economically
feasible if the kiln is *too* leaky.
As for when to introduce the gas, I would think you'd need to do it
considerably sooner than at 900. When I'm *trying* to add those pretty
browns, maroons, blues, or silvers to a piece of copper, I can do so
by putting it in an oven at 350 F.
Bert (the un-Weiss)
"Sundog" <alw...@mybest.com> wrote:
>
>Bert __ I dunno' Bert, I think Bert may be onto something here. [?] How
>about a steady flow of Argon or such, the inert stuff welders use. Perhaps
>it could be introduced at around 900 and stopped once the glass has sealed
>the copper at say 1300-1400, then venting resumed. I doubt if a perfect seal
>and absolutely oxygen free environment is even needed to get a big reduction
>in the oxidation problem [ problem? I like the maroon color myself] You
>could run the kiln at full throttle in that range for a minimum time at
>fusing temp. They make vacuum chamber kilns so why not this idea? My
>curiosity is piqued. Someone else try it and let me know .... heh heh heh..
>>
>>Kilns can not possibly tight enough to achieve what you propose. In order
>>to exit the element from the kiln there must be plenty of air available for
>>the element wire to cool, otherwise it disintegrates. That is not to
>mention
>>that there must be a way for gasses and moisture to escape if one is firing
>>enamels or overglazes.
>>>
Bert
(used in MIG welding), both of which are heavier than air. I imagine
carbon dioxide would be quite a bit cheaper, and according to a
welding book I have it has better thermal conductivity. Of course, if
the copper were situated closer to the top of the kiln, you might want
to use something *lighter* than air, like helium. ;-)
Bert
Bert
>Bert
>
>How dare you use my name. It is a good thing this is a newsgroup, because
>if I were in your presence I'd have to kill you.
Whoa, dude! You're, like, so lucky you have a newsgroup to hide in --
otherwise I'd have to break out a big ole can of Whoop-Ass.
>Kilns can not possibly tight enough to achieve what you propose. In order
>to exit the element from the kiln there must be plenty of air available for
>the element wire to cool, otherwise it disintegrates. That is not to mention
>that there must be a way for gasses and moisture to escape if one is firing
>enamels or overglazes.
I think you may have misinterpreted my proposal. I was thinking in
terms of a constant flow approach, not a fill-it-and-forget-it
approach. Whether the flow would need to be a trickle or a flood
depends on how leaky the kiln is.
Well now, this was not at all what I expected. I envisioned a site
devoted to Catbert, the evil human resources director / consultant in
the Dilbert comic strip...
Bert (the wise-guy, not the Weiss guy)
>> From: Bert <no_...@thank.you>
>> Organization: MindSpring Enterprises
>> Reply-To: no_...@thank.you
>> Newsgroups: rec.crafts.glass
>> Date: Wed, 24 May 2000 02:52:51 -0500
>> Subject: Re: Fused Glass with Shiny Copper
>>
>> I have an idea, but since I have no experience working with glass (or
>> with kilns for that matter) I don't know how feasible and/or effective
>> it might be. The idea is to rig a gas nozzle in such a way as to keep
>> the kiln chamber filled with an inert gas from the time you start
>> firing until the glass has completely fused around the copper. This
>> should prevent the copper from oxidizing and changing colors -- it's
>> the same basic concept as inert gas welding. I don't know how well
>> sealed a typical kiln is, so I have no idea how much gas would be
>> required. Just a thought...
>>
>> Bert
>>
>> "Barbara Cashman" <bjca...@mindspring.com> wrote:
>>
>>> I'll have to give you another opinion on this. Tried for 10 years to get
>>> the copper color to stay in the glass when I was firing in the stationary
>>> kilns. It always burned out. The production kiln, however, got it every
>>> time. I recommend as fast a fire as possible--rather than slow. You need
>>> to seal that edge as quickly as you can to seal the copper. In any case, I
>>> suggest you do it both ways and see what works for you.
>>>
>>> Barbara
>>> www.glastile.com
>>>
>>>> "The Crafty Owl" <craf...@kenelise.demon.co.uk> wrote in message
>>>> news:Gqfy5dAK...@kenelise.demon.co.uk...
>>>>> Just my trial-and-error, but I've found that to keep the shine the
>>>>> copper has to get sealed in, with no air bubbles, while the temperature
>>>>> is still fairly low. So if you put down the thin copper onto glass, then
>>>>> a sheet of thin glass, and take it far enough for the top glass to fuse
>>>>> with the bottom, you can then use that sandwich in other things, and
>>>>> take the temp higher. I've only used VERY thin copper, basically leaf.
>>>>> Hope that works for you.
Bobfuses
<no_...@thank.you> writes:
>I was thinking maybe argon (used in TIG welding) or carbon dioxide
>(used in MIG welding), both of which are heavier than air. I imagine
>carbon dioxide would be quite a bit cheaper, and according to a
>welding book I have it has better thermal conductivity. Of course, if
>the copper were situated closer to the top of the kiln, you might want
>to use something *lighter* than air, like helium. ;-)
>
>Bert
I am thinking nitrogen. It is inert, heavier than air and fairly commonly
available. I suspect that a tube introduced through the bottom of the kiln
under the shelf might do the trick in a simple way. Should not take much volume
to maintain a nice nitrogen blanket in the kiln. It would likely change the
heating charastics of the kiln due to whatever the heat conductivity of N2 is.
Bob in 92026
Bert Weiss
Just kidding.
Isn't messing around with gasses dangerous?
Bert
Bert Weiss Art Glass
http://www.customartglass.com
Furniture Sculpture Lighting Tableware
Architectural Commissions
Barbara Cashman
tunnel, so there is a rolling air current that occurs in that environment.
Air makes a difference.
Barbara
"Gary @mosquitonet.com >" <ggrata<nospamremovenospam> wrote in message
news:KTKW4.1352$S14....@newsfeed.slurp.net...
> Barbara...... please explain the differences between a stationary kiln and
> production kiln... I have no idea.....thanks
> Gary
>
> "Barbara Cashman" <bjca...@mindspring.com> wrote in message
> news:8gf1s1$phf$1...@slb0.atl.mindspring.net...
> > I'll have to give you another opinion on this. Tried for 10 years to
get
> > the copper color to stay in the glass when I was firing in the
stationary
> > kilns. It always burned out. The production kiln, however, got it
every
> > time. I recommend as fast a fire as possible--rather than slow. You
need
> > to seal that edge as quickly as you can to seal the copper. In any
case,
> I
> > suggest you do it both ways and see what works for you.
> >
> > Barbara
> > www.glastile.com
> >
> >
> >
> > "Glenn Woolum" <gwooly-...@earthlink.net> wrote in message
> > news:o1DW4.25679$T41.5...@newsread1.prod.itd.earthlink.net...
> > > Thanks for the suggestion. I'll definately give it a try.
> > >
> > > --
> > >
> > > Regards,
> > > Glenn Woolum
> > >
Barbara Cashman
air flow is the key. I agree that the glue has an influence in the firing.
I found if I glued the copper in place, the whole thing turned red--even in
the tunnel kiln. Seems it needs to move. But, whatever, the fast seal
makes the difference. I mass-produce 4x4 and 6x6 standard sized
copper-encased glass tiles for the tile industry. I only slump the encased
copper to a bowl after a full fuse--when I do that at all for a custom
order. My real business in the tile.
"Tom White" <tomw...@earthlink.net> wrote in message
news:392BCF58...@earthlink.net...
Bert
Actually, nitrogen isn't heavier than air, it *is* air (78% of it
anyway). More importantly though, N2 is just slightly lighter than O2.
On the other hand, CO2 and argon are considerably heavier than air
(and O2), so they should be more effective at shielding the work.
Having said that, a steady flow of N2 over the workpiece might work
well enough. I have no idea how the cost and availability of N2
compare with those of CO2.
Bert
sara...@my-deja.com
Hey, you are on the right track. This is sketchy info on my part
'cause I haven't done it, but have talked with the guy in the Bay Area
who has and I'll now share my cryptic notes here. He has a stream
of Argon that he feeds through a maniford using "stopcocks" to
keep the flow of gas going through the kiln because he uses
graphite molds and doesn't want them to decompose. The argon
makes an envelope around the graphite and it doesn't powder
down. I must assume that the same could be done to keep
anything from oxydizing. when someone tries this let me know. My
husband understands my notes better than I, we just haven't taken
the time, or had the need, to try this. If anyone is really serious
about getting better instructions email me and I'll give you his
phone number, he also makes some small, inexpensive kiln
controllers and other fun stuff.
Have fun and let me know the results,
Sara
http://www.creekmore-glass.com
>How about a steady flow of Argon or such, the inert stuff welders
use. Perhaps
> it could be introduced at around 900 and stopped once the glass
has sealed
> the copper at say 1300-1400, then venting resumed. I doubt if a
perfect seal
> and absolutely oxygen free environment is even needed to get a
big reduction
> in the oxidation problem [ problem?
- - -
> >> I have an idea, but since I have no experience working with
glass (or
> >> with kilns for that matter) I don't know how feasible and/or
effective
> >> it might be. The idea is to rig a gas nozzle in such a way as to
keep
> >> the kiln chamber filled with an inert gas from the time you
start
> >> firing until the glass has completely fused around the copper.
This
> >> should prevent the copper from oxidizing and changing colors
-- it's
> >> the same basic concept as inert gas welding. I don't know
how well
> >> sealed a typical kiln is, so I have no idea how much gas
would be
> >> required. Just a thought...
Sent via Deja.com http://www.deja.com/
Before you buy.
Michele Blank
the oxidation? wouldn't a similar reaction be possible to achieve with
fusing? or am I just oversimplifying? Michele
Eric
Bobfuses <bobf...@aol.com> wrote in message
news:20000524183218...@nso-cv.aol.com...
<snip>
> I am thinking nitrogen. It is inert, heavier than air and fairly commonly
> available. I suspect that a tube introduced through the bottom of the kiln
> under the shelf might do the trick in a simple way. Should not take much
volume
> to maintain a nice nitrogen blanket in the kiln. It would likely change
the
> heating charastics of the kiln due to whatever the heat conductivity of N2
is.
> Bob in 92026
Since air is just about 80% nitrogen, and since oygen and nitrogen have
similar thermal conduction values, putting nitrogen in the kiln won't change
anything so you'd know it.
Eric
Eric
Bert <no_...@thank.you> wrote in message
> bobf...@aol.com (Bobfuses) wrote:
<snip>
> Actually, nitrogen isn't heavier than air, it *is* air (78% of it
> anyway). More importantly though, N2 is just slightly lighter than O2.
> On the other hand, CO2 and argon are considerably heavier than air
> (and O2), so they should be more effective at shielding the work.
> Having said that, a steady flow of N2 over the workpiece might work
> well enough. I have no idea how the cost and availability of N2
> compare with those of CO2.
Good, pure nitrogen is pretty cheap. Really cheap. Call your local welding
supply place and ask.
Eric
Bobfuses
<rico.t...@campquake.com> writes:
>Since air is just about 80% nitrogen, and since oygen and nitrogen have
>similar thermal conduction values, putting nitrogen in the kiln won't change
>anything so you'd know it.
>
>Eric
Now I an wondering if putting something in the kiln, like charcoal briquets
under the shelf, would eat up the O2? Now that would be a simple solution!
Bob in 92026
Steve
I did the briquet thing when I was trying for a reducing atmosphere
for chemical effects in glass, and it didn't work to the extent that
I'd hoped. Just to prevent oxidation on copper? Might do the trick,
HOWEVER, there are (at least) two other considerations here, and they
are:
1) Elements need the coating of oxide on them to keep them from
burning up,
2) If you get an "excess" of carbon in the kiln, you end up with
carbon monoxide, and then need to be very conscious of ventilating
the shop.
--
Steve Ackman
Manager, New Age Forum http://www.delphi.com/newage
Glass Host, Arts & Crafts http://www.delphi.com/crafts
Metamorphosis Glassworks Page http://people.delphi.com/stackman
Bobfuses
writes:
>
>1) Elements need the coating of oxide on them to keep them from
> burning up,
I understand this to be true. But once the elements have been fired I would
think that the coat of oxide would have been formed. Would an O2 poor condition
remove it? I dono and seek the correct answer.
I have heard warnings against salt reduction firings for unstated reasons
except that the elements were not guaranteed in such firings.
Bob in 92026
Terry Harper
>
>Now I an wondering if putting something in the kiln, like charcoal briquets
>under the shelf, would eat up the O2? Now that would be a simple solution!
Did it once, with an induction heated set-up, using a graphite susceptor
under a glass bell jar. The bell jar was flushed slowly with commercial
nitrogen, which contains a small amount of oxygen (~1%). This created
reducing conditions in the melting chamber.
--
Terry Harper, Web Co-ordinator, The Omnibus Society
http://www.omnibussoc.org
E-mail: terry....@btinternet.com
URL: http://www.terry.harper.btinternet.co.uk/
glass...@my-deja.com
In article <Gqfy5dAK...@kenelise.demon.co.uk>,
You said you have used copper leaf... I've tried fusing various types
of leaf... gold... silver... all burn out. Have you had any luck?
Laura
The Crafty Owl <craf...@kenelise.demon.co.uk> wrote:
> Just my trial-and-error, but I've found that to keep the shine the
> copper has to get sealed in, with no air bubbles, while the
temperature
> is still fairly low. So if you put down the thin copper onto glass,
then
> a sheet of thin glass, and take it far enough for the top glass to
fuse
> with the bottom, you can then use that sandwich in other things, and
> take the temp higher. I've only used VERY thin copper, basically leaf.
> Hope that works for you.
> ___
> <*,*>
> {'-'} The Crafty Owl
> -"-"-
>
Barbara Cashman
color. Use gold or silver FOIL, rather than leaf, if you want to keep the
color, or fire the leaf 3-4 sheets thick. Only way I've been able to do it,
unless some else has a better suggestion.
Barbara
<glass...@my-deja.com> wrote in message
news:8grtj4$49v$1...@nnrp1.deja.com...
Steve
>
> >
> >1) Elements need the coating of oxide on them to keep them from
> > burning up,
>
> I understand this to be true. But once the elements have been fired I would
> think that the coat of oxide would have been formed. Would an O2 poor condition
> remove it? I dono and seek the correct answer.
Carbon monoxide is not only oxygen poor. It's an extremely
powerful reducing agent, which will easily strip the oxide off your
elements.
Merely "oxygen poor," such as nitrogen, argon or carbon dioxide
would be detrimental to the oxide coating at a much lower rate, if
at all.
> I have heard warnings against salt reduction firings for unstated reasons
> except that the elements were not guaranteed in such firings.
By shovelling common salt into the firemouth of the kiln,
a skin of glaze forms from the sodium on the ware and kiln
walls alike, while the chlorine burns off as a poisonous
gas. Needless to say, such glazes require the exclusive use
of an outdoor, fuel burning kiln with a flue. - Tony Birks in
The Complete Potter's Companion
I'm not sure of the chemistry involved here, but I would imagine that
the chlorine would replace the protective oxide coating on the elements
with a chloride.