slumping on to a face mold

chris webb · Post by **chris webb** » Sat May 24, 2003 12:04 pm

I recently purchaced this ceramic bisque vase, it is a womans face on the front and a really cool wavy pattern on the back. I would like to slump glass over the face and have it end up with a lip around the edge that I can use to either mount it to a base or foil and put it in a stained glass piece. I know I will need to drill some holes in the mold first, is there a patter/place I need to worry more about putting the holes? the nose on the mold is the highest point and it is quite pointy (is that a word? LOL) and the glass would have to be balanced on it to begin with. I reckon I will have to go really slow so that it slumps evenly and doesn't get thin in places. Was thinking about making a nest in fiber blanket that it can nestle into and have the fiber blanket come up the sided then place thick fiber paper around the sides so that it forms and even lip (don't need much of a lip).. Anyway since I am pretty new to the slumping thing, am I way off base here? will this have a chance of working? I would greatly appreciate any and all help.

Strega · Post by **Strega** » Sat May 24, 2003 1:39 pm

I do almost all my slumps on thriftstore finds, though I haven't tried one as complicated as this. It sounds FUN. THis isn't glazed or painted, is it? Because the glass will stick and you will have a lovely glass covered vase. If it is unglazed ceramic or teracotta, make sure you cover it well with kiln wash, but not so heavy you lose details. If it is plaster it doesn't need kiln wash but "might" fall apart. I have plaster pieces that worked well.
You may want to drill the holes in the glass when you are done. I think that would be easier, though it sounds scary . I find that glass is more forgiving than ceramic, and you only have the one mold, you can make more glass. But I am sure many on this list have different experiences. There is no one way of doing this stuff.
I think your idea with the fiber is one way to go. Another would be to build a shelf around it in fiberboard. Suspending the glass wth wire also might be an idea to brainstorm on. I think you are going to have to cold work it afterwards no matter what, unless you get lucky!
I haven't had problems with long soaks causing things to be too thin, but I'm not really picky about that. I love long soaks. Glass wants to stay together, wants to be the same thickness. I have had problems occasionally with fractures when the weight of the glass over a steep angle was too much for the glass to hold together. I think long soaks prevents this. Make sure the glass is thick enough.
My best advice is: think of it as an experiment, and you may have to do it more than once, so don't start with an expensive piece of glass or one you have put time into a complicated fusing. You may even want to try with window glass first, though remember that the times and temps for window glass are different (higher, I've found) than "good" glass. It is ok to have high expectations but expect to be surprised. And the experiments make excellent garden ornaments.

Strega · Post by **Strega** » Sat May 24, 2003 1:42 pm

And don't even THINK about NOT doing this, or I will be mad at you!

chris webb · Post by **chris webb** » Sat May 24, 2003 2:33 pm

Ok thanks Strega, the holes are for the mold to let the air go out and not trap bubbles. I use the high fire kiln wash (the pink stuff) it seems to work good on the few bowl molds that I have tried. I will try to post a pic of it if it comes out at all. With my work schedule tho I may not get to it till the middle of the week, trying to get ready for a little bead/jewelry show on june 7th. thank you for your response
ps it is bisque ceramic mold not been glazed at all

Tom White · Post by **Tom White** » Sun May 25, 2003 2:49 am

Since glass shrinks more than ceramic bisque upon cooling I am concerned that if you slump glass over the face part of your bisque mold and allow the glass to go over the edge of your mold you run a very real risk of locking the glass onto the mold or having the glass crack as it cools. You might be able to minimize this risk if you can build up fiber or board next to your bisque mold to the point that the edges of your glass are not allowed to fall over the edges of your bisque mold enough to lock onto it. From your description of your mold (vase) I would think that total slump depth of 1/2" to 3/4" might be the deepest you might expect to get without probems. Another thought might be to construct fiber board walls either on two opposite sides or on all four sides of your mold which are slightly taller than the tallest point of your mold to support your glass over the mold and allow it to slump down onto the mold when the glass softens. Unwanted edges could be cut off after slumping, leaving your face relief with a flange around it.

Best wishes,
Tom in Texas

Colin & Helen · Post by **Colin & Helen** » Sun May 25, 2003 5:16 am

Tom White wrote:Since glass shrinks more than ceramic bisque upon cooling I am concerned that if you slump glass over the face part of your bisque mold and allow the glass to go over the edge of your mold you run a very real risk of locking the glass onto the mold or having the glass crack as it coolsBest wishes,
Tom in Texas

Or... why not coat the vase with release agent i.e. Vaseline then take a plaster/silica mould ..that's if the original has very few undercuts....then slump into the mould...Col

Gale aka artistefem · Post by **Gale aka artistefem** » Sun May 25, 2003 7:42 am

You can do this type of slump. It's not impossible, but it will take a few steps of going into the kiln to do this. Colin is right about making it easy on yourself by taking a casting of the vase and making a reverse mold to slump into.

If you want to slump over the vase, the toughest part will be balancing the sheet of glass on the single highpoint of the nose. Your idea of building up fiber blanket around the mold perimeter is good. Build up at least a couple of points with fire brick or kiln furniture with fiber blanket topping. Build these up high enough to help initially support the glass.

You will have to shut off the kiln, open it up and remove the surrounding perimeter support system once the glass has softened enough to begin slumping down over the nose area. Be quick with this support removal - you don't want to lose too much of the kiln heat.

It's been my experience that the glass is compromised if you let the temperature fall into the glass strain point area.

Do you have heat protective clothing for this job? Kevlar arm covers, gloves, apron? Protective eyewear? (Whatever you do, don't wear polyester or acrylic clothing. You'll fry yourself by becoming one with your synthetic clothing - cotton is good.) After you remove the outer supports, turn the kiln back on, and slowly ramp back up to slump temp.

You will have to go back into the kiln during the cool down. During the 1200 to 1275 degree range, Be sure the kiln is shut off, open it back up and gently lift one edge of the glass up off the mold so the glass surface is not in full contact with the mold. I use a long metal rod that has one end bent into a small hook. This glass shifting will keep the glass from breaking as it cools and shrinks over the mold. You should turn the kiln back on once again to bring it back up to the temp it was at when you did this second opening. Then resume your annealing schedule.

Good luck.

Not to throw water on your glass endeavor, (this would cause steam???)but this is something we all should be aware of when buying ready-made objects to use as molds for our glass work.

Are you possibly infringing on a copyright? Who holds the copyright for the design and artwork of this vase? Is your slumped piece going to remain in your collection for your own personal use or will you be selling the finished glass piece?

You don't have to answer these questions, they are just rhetorical in further discussing copyright issues. Where is the line for using ready-made objects?

Gale aka artistefem · Post by **Gale aka artistefem** » Sun May 25, 2003 7:55 am

Post moved to business forum.

chris webb · Post by **chris webb** » Sun May 25, 2003 8:32 am

Well, these responses are really getting me thinking on the options. I've never made a mold myself tho I'm excited to try. I think this would give me the best chance at it working. One question I have is this, do you get more detail from slumping the glass over a mold such as this or into one? I'll take a stab at answering this so ya'll can tell me if I am on track here, would think that you would get more detail from going in with a nice slow schedule and good soak time than you could get from slumping over it. My reasoning for thinkin this is by slumping over it and using a long soak time you have more chance of the thinning out over the high points. Please explaine if I am off base here. Sometime I'm sure I'll want to do something that requires me to go into the kiln hot but at this time I think it is a little intimidating

at this time and I don't have enough protective wear.
Gale that is a very good question on the copywrite issue, I have no idea what the answer is. With this project it is moot anyway as it is for me and mostly a teaching myself thing. BTW haven't I seen you over on wetcanvas as well? That is where I hang out the most as I do much more torch work than fusing at the moment. It looks like this is changing tho, I find I have more talent in the murrini making than in the bead making and like off mandrell better than on so I figure to combine my love of fusing and torchwork and see what happens.
Colin could you define a little for me how much of an undercut I need to worry about and can I find directions on making the mold in the second Lundsrtom book?
thanks everyone

Bert Weiss · Post by **Bert Weiss** » Sun May 25, 2003 10:53 am

chris webb wrote:I recently purchaced this ceramic bisque vase, it is a womans face on the front and a really cool wavy pattern on the back. I would like to slump glass over the face and have it end up with a lip around the edge that I can use to either mount it to a base or foil and put it in a stained glass piece.

I have tried this and it will fail every time. (unless you remove the glass from the mold below the softening point and above the anneal soak temps.) Glass shrinks more than ceramic when cooling, so the glass will form beautifully and then crack. What will work is making a casting plaster mold and slumping over that. In order to do this you need a rubber negative mold in which to cast a plaster positive. There are numerous plaster formulas that work for glass casting, see archives or buy Lundstrom "Glass Casting and Mold Making"

Ron Coleman · Post by **Ron Coleman** » Sun May 25, 2003 11:04 am

Gale aka artistefem wrote:
Not to throw water on your glass endeavor, (this would cause steam???)but this is something we all should be aware of when buying ready-made objects to use as molds for our glass work.

Are you possibly infringing on a copyright? Who holds the copyright for the design and artwork of this vase? Is your slumped piece going to remain in your collection for your own personal use or will you be selling the finished glass piece?

You don't have to answer these questions, they are just rhetorical in further discussing copyright issues. Where is the line for using ready-made objects?

My take on the subject is this. Someone designs plates and vases and copyrights the designs, they sell the designs to mold makers. The mold makers make molds and sell them to the ceramic shops. the ceramic shops pour hundreds of plates using the molds and sell greenware or bisque fired pieces for people to paint and fire. The people that buy the greenware may use the pieces or sell them.

The whole thing is about making money using the free enterprise system. The end use of the product isn't part of the equation from my point of view. You buy a greenware piece to use as a mold for your glass, other people buy the greenware to paint and eat dinner off of or sell.

The ceramic shop made money by selling you the greenware and they don't have to pay any royalities on the use of the mold. The money works its way back into the system when they buy molds from the mold maker which in turn pays for designs. The more popular the design, the more money everyone makes. The ceramic shop would love to have glass fusers buy more greenware for molds and the mold makers would love to sell more molds and the designers would love it too.

The whole operation is controlled by the copyright process in that if you want a particular design you have to pay for it. Now if someone along the way decides to go around the process and make their own mold based on the original design, that's where the copyright get violated in my estimation.

This may not hold true if you make a mold of something like a Corning Ware plate and start selling your glass designs based on their shapes. That wasn't the intended use of their product from my point of view and would violate the copyright design.

Ron

Bert Weiss · Post by **Bert Weiss** » Sun May 25, 2003 12:01 pm

Chris & Gale

I have been able to balance the glass over the nose and get a good slump that flattens out around the the perimeter of the face. Just heat slowly (I use a top firing kiln, a side firing one might be trickier?) I think that you will get a much better resolution slumping over the face than in to.

I think it is much simpler to make a plaster mold than to mess around with removing the glass from a bisqued mold while hot. (and I do have kevlar gloves and the experience to do it).

The mold making procedure I used was to do a paint on vinyl rubber mold over the face, that is backed up with a plaster "mother". The rubber is relatively thin, so the plaster backup keeps the rubber in the right shape. You paint on the rubber and then build a wood box around it and cast straight plaster in the box. Then I did a 2 part casting plaster pour. The first part is a skim coat of plaster/silica for resolution. This is backed up with plaster/silica/grog. The backup mix must have a minimum of water so that it is thick and strong.

Then you simply place the face on a kiln washed shelf, place a larger piece of glass balanced on the nose, and heat slowly to 1000 and then up to the top temp depending on the glass you are using. You should be able to see that the perimeter glass has settled down flat to the kiln shelf. At that point the resolution is likely there.

Now you have a mold capable of remaking the face over and over. If you are careful and the face has no undercuts, you can likely reuse the plaster a few times, maybe.

Using low fire enamels you can paint on the face and fire to 1050 without losing it's shape. Using a glass cutter, you can trim or remove the part of the glass that settled on the kiln shelf.

Did I mention that there is a learning curve to do all of this seamlessly? Once you figure it all out, you deserve the big bucks.

chris webb · Post by **chris webb** » Sun May 25, 2003 12:24 pm

Bert, yepper, be a long time before I'll deserve the "big bucks" LOL but it'll be a heck of alot of fun experimenting. I'm going to ask you a real duh question here and be glad I'm not physically close enough for you to slap me. Keep in mind I am a hands on visual learner, I got the part about painting on the rubber mold over the face but the next part where I make a box around it and make a mother mold confused me. A rubber mold and then pour plaster into box around mold which would make a mold that you could slump into right? but not going to, you are going to use that one to make another mold that you can slump over right? I'm also not sure what the "skim coat" would be. I'm thinking when I get off work today I'm going to be reading that mold making "book 2" I have at home.

My husband will prabobly read your post and know exactly what you are talking about

thank you so much

Ron Coleman · Post by **Ron Coleman** » Sun May 25, 2003 12:55 pm

Ron Coleman wrote:
Gale aka artistefem wrote:
Not to throw water on your glass endeavor, (this would cause steam???)but this is something we all should be aware of when buying ready-made objects to use as molds for our glass work.

Are you possibly infringing on a copyright? Who holds the copyright for the design and artwork of this vase? Is your slumped piece going to remain in your collection for your own personal use or will you be selling the finished glass piece?

You don't have to answer these questions, they are just rhetorical in further discussing copyright issues. Where is the line for using ready-made objects?
My take on the subject is this. Someone designs plates and vases and copyrights the designs, they sell the designs to mold makers. The mold makers make molds and sell them to the ceramic shops. the ceramic shops pour hundreds of plates using the molds and sell greenware or bisque fired pieces for people to paint and fire. The people that buy the greenware may use the pieces or sell them.

The whole thing is about making money using the free enterprise system. The end use of the product isn't part of the equation from my point of view. You buy a greenware piece to use as a mold for your glass, other people buy the greenware to paint and eat dinner off of or sell.

The ceramic shop made money by selling you the greenware and they don't have to pay any royalities on the use of the mold. The money works its way back into the system when they buy molds from the mold maker which in turn pays for designs. The more popular the design, the more money everyone makes. The ceramic shop would love to have glass fusers buy more greenware for molds and the mold makers would love to sell more molds and the designers would love it too.

The whole operation is controlled by the copyright process in that if you want a particular design you have to pay for it. Now if someone along the way decides to go around the process and make their own mold based on the original design, that's where the copyright get violated in my estimation.

This may not hold true if you make a mold of something like a Corning Ware plate and start selling your glass designs based on their shapes. That wasn't the intended use of their product from my point of view and would violate the copyright design.

Ron

The more I think about this topic I'm inclined to take a 180 degree turn on what I previously said.

If you profit from the use of anyone's copyrighted design, be it greenware or using the piece to make a mold, it probably is a violation of the copyright. Using greenware to make bowls and plates and then in turn. sell them would violate the copyrighted design. For your own use, it probably doesn't make any difference.

They should change the words "Copyright" to"No Right To Copy".

Ron

chris webb · Post by **chris webb** » Sun May 25, 2003 12:58 pm

I just had a thought, what if I got the mold in greenware and had them give it to me wet of wet it and cut and shape so that it doesn't have the steep sides, do you think that would work?
chris

Rob Morey · Post by **Rob Morey** » Sun May 25, 2003 1:45 pm

Chris,
Here are a few sites that might help you. Some are.. shall we say, uh, simple. The process is explained though.

http://www.dalzell.net/ceramics/moldmak ... aking.html

http://www.garlic.com/~blufrogg/dolls/mold.htm

If you want to do your own casting of someone's face, use dental alginate. It's the same thing that dentists use to cast your teeth. No mold release needed. As soon as you take it off, put it in a box of shipping peanuts or something like that, and fill with hydro-perm or some other high fire casting plaster. Sand down all of the undercuts and drill a couple of holes in the area where the eyes are close to the nose to allow air to release. You should do this with the vase that you have. You can use kiln furniture to hold the glass just above the nose. Allow the glass to drop down over the nose and when it seems that the glass won't slip and fall off, open the kiln and knock the furniture out of the way, (turn the power off to the kiln and always wear the appropriate safety equipment.) Then continue firing. The result will be a rather, ghost like appearance. If you want detail, then you have to make a negative of your plaster casting and drop the glass into that.

Hope this is of some help.

Rob

Suzan · Post by **Suzan** » Mon May 26, 2003 10:05 am

Another fun thing to try is to buy plaster gauze from a hobby or art supply shop. Cut into strips, dip quickly in a bowl of water, and apply the strips onto the face of a Vaseline-smeared volunteer. Be careful not to block their nostrils, and apply 2 layers.

After it has dried for about 20 minutes, get your volunteer to gently move their facial muscles about and remove the mold. Continue adding a few layers of plaster gauze to strengthen the mold. Then, use desired casting medium to create positive and/or negative castings for molds. Loads of fun and no copyright problems!

Cheers,
Suzan

WarmGlass.com

slumping on to a face mold

slumping on to a face mold

Greenware copyrights

Re: slumping on to a face mold