I'm a jeweler and want to make some very small 3/4" drop molds in various shapes.
I'm metal literate and since it is flat, cuts nicely I'm hoping I can make some outta silver, copper, or brass. I will kiln wash them before I put the glass on them. I choose these as I have them and tools that will shape them easily. Also I will probably use thin window glass, or maybe BE.
Is there any problems with this? Is the expansion/contraction difference between any of these metals such to make them unusable as a drop mold?
Thanks
Carla
Making Itty Bitty Drop Molds?
Moderators: Brad Walker, Tony Smith
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Carla
PS to making itty bitty drop molds
I have been told privately that I have asked a really stoopid question and should delete my post to save myself embarassment.
The reason my post critic gave for my stupidity was that the metals I want to use will melt. My glass experience is limited to 2 years of playing around but I have many more years of metal experience. I know what these metal melts at:
Sterling sliver will melt at: 1761°
Copper will melt at: 1981°
Brass will melt at: 1750°
These temps seem to be way above what I would slump a small piece of glass at.
So the post and question stands for now. Can very small drop rings be made from these metals?
If my critic is correct and I have embarassed myself and subjected this board to a horrendously dumb question, I apologize.
Carla
foxon@bendnet.com
if ya want to berate me some more off forum
The reason my post critic gave for my stupidity was that the metals I want to use will melt. My glass experience is limited to 2 years of playing around but I have many more years of metal experience. I know what these metal melts at:
Sterling sliver will melt at: 1761°
Copper will melt at: 1981°
Brass will melt at: 1750°
These temps seem to be way above what I would slump a small piece of glass at.
So the post and question stands for now. Can very small drop rings be made from these metals?
If my critic is correct and I have embarassed myself and subjected this board to a horrendously dumb question, I apologize.
Carla
foxon@bendnet.com
if ya want to berate me some more off forum
I'm pretty new here (actually, this is my first post!), but I hope I have the right to say that anyone that made you feel stupid for asking was wrong, although I will give them credit for taking it off the board and not making it public. I'm afraid you did that... 
At any rate, I'm afraid that people that pick on people that are not as knowledgeable as they are quite frankly miss the point of bulletin board communities. I think that people are here to share knowledge and camaraderie and keep the craft alive. Having said all that, I'm clearly more stupid than you are, since I don't even have a clue as to what drop molds are!
Take it easy,
At any rate, I'm afraid that people that pick on people that are not as knowledgeable as they are quite frankly miss the point of bulletin board communities. I think that people are here to share knowledge and camaraderie and keep the craft alive. Having said all that, I'm clearly more stupid than you are, since I don't even have a clue as to what drop molds are!
Take it easy,
Barb
Re: Making Itty Bitty Drop Molds?
Carla wrote:I'm a jeweler and want to make some very small 3/4" drop molds in various shapes.
I'm metal literate and since it is flat, cuts nicely I'm hoping I can make some outta silver, copper, or brass. I will kiln wash them before I put the glass on them. I choose these as I have them and tools that will shape them easily. Also I will probably use thin window glass, or maybe BE.
Is there any problems with this? Is the expansion/contraction difference between any of these metals such to make them unusable as a drop mold?
Thanks
Carla
I haven't tried what you're trying to do this Carla but I have used various metals.
You know the melting point of silver is lower than glass fusing temp so the other metals you mentioned would hold up better.
Using shelf primer/kiln wash might be a bit rough for something so delicate; a lady brought some of her beads to my studio on Tuesday and what she uses to release the bead from the mandrel is called bead release (surprise!) and it's supposed to be available from your supplier. Quill recently joined the board, she has some info about it in the tutorial on her website.
As for the metal mould shrinking, I would think the metals would be ductile enough to move with the glass, it being so thin in proportion to the glass. Again, the bead seperator would allow it to 'move' underneath the glass.
Whatever you do, keep us posted with your progress.
Paul
It ain't where you're from, it's where you're at!
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Tony Smith
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Carla,
There are no stupid questions, just stupid comments.
With that said, the answer is: I don't know. Conventional wisdom says that a drop ring mold should be made of a material that has a lower COE than glass so that the glass isn't trapped inside the ring. BUT, depending on the shape and design of the drop ring, it may work. For example, if the drop ring was sufficiently malleable, as in the case of thin copper, it will stretch as it shrinks around the glass, but could easily be cut off without damaging the glass. Or if the dropring was split in one or more places, it could possibly be removed and reused without damaging either the ring or the glass. In addition, a layer of ceramic fiber on top of the ring may add sufficient compliance (and insulation) to allow these metals to be used as a dropring. Or, if you were to be creative, a sufficiently malleable material could be trimmed and left in place as a decorative element.
Another question is whether or not the high thermal conductivity of these materials would create a problem by acting like a heat sink and causing uneven cooling at the top of the ring. As I just mentioned, the ceramic fiber may mitigate this effect.
You will have to use some type of release on whatever metal you try, and you should probably start with kilnwash. Roughen up the surface a bit and heat the metal to 500 degrees or so before applying the kilnwash to make it stick a little better.
So keep the questions coming. Many of us are still interested in helping others to learn. In the process, we often learn something ourselves.
Tony
There are no stupid questions, just stupid comments.
With that said, the answer is: I don't know. Conventional wisdom says that a drop ring mold should be made of a material that has a lower COE than glass so that the glass isn't trapped inside the ring. BUT, depending on the shape and design of the drop ring, it may work. For example, if the drop ring was sufficiently malleable, as in the case of thin copper, it will stretch as it shrinks around the glass, but could easily be cut off without damaging the glass. Or if the dropring was split in one or more places, it could possibly be removed and reused without damaging either the ring or the glass. In addition, a layer of ceramic fiber on top of the ring may add sufficient compliance (and insulation) to allow these metals to be used as a dropring. Or, if you were to be creative, a sufficiently malleable material could be trimmed and left in place as a decorative element.
Another question is whether or not the high thermal conductivity of these materials would create a problem by acting like a heat sink and causing uneven cooling at the top of the ring. As I just mentioned, the ceramic fiber may mitigate this effect.
You will have to use some type of release on whatever metal you try, and you should probably start with kilnwash. Roughen up the surface a bit and heat the metal to 500 degrees or so before applying the kilnwash to make it stick a little better.
So keep the questions coming. Many of us are still interested in helping others to learn. In the process, we often learn something ourselves.
Tony
Last edited by Tony Smith on Fri Apr 11, 2003 10:58 pm, edited 1 time in total.
The tightrope between being strange and being creative is too narrow to walk without occasionally landing on both sides..." Scott Berkun
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rosanna gusler
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hi carla, there are no stupid questions. there are however stupid and mean sprirted answers. i wouldn't take any mean spirited sneak attacks too seriously. that said, i think that you might be happier making your drop molds out of clay or rigidised fiber paper. what ever is easier to get your hands on. there is alot of info on both these in brads tutorial here and in the archives of this site. what are you planning to make? rosanna
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Gale aka artistefem
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Glad to see you here Carla and please continue to ask whatever questions you need answered about kiln-forming glass.
One of the great things about this board is that we can and do usually rise above the occasional idiocies...........
I agree with Rosanna - you might have better success doing your glass drop through a ring of fiber board or through a hard fired clay form, then seperately cutting and fitting your metal to fit the slumped glass.
When trying to fire metals with glass, it's a tricky balance getting just the right amount of glass and metal to bond with an "acceptable amount" of stress. There's always going to be some stress between the glass and metal. Their thermal expansion/contraction rates are close and the metal will sometimes flex to accomodate the cooling shrinking glass, but the more metal surface you have in contact with the glass the more likely you will get stress breakage.
You might try designing your piece with smaller amounts of metal in contact with the glass if it's important for you to fuse them together.
One of the great things about this board is that we can and do usually rise above the occasional idiocies...........
I agree with Rosanna - you might have better success doing your glass drop through a ring of fiber board or through a hard fired clay form, then seperately cutting and fitting your metal to fit the slumped glass.
When trying to fire metals with glass, it's a tricky balance getting just the right amount of glass and metal to bond with an "acceptable amount" of stress. There's always going to be some stress between the glass and metal. Their thermal expansion/contraction rates are close and the metal will sometimes flex to accomodate the cooling shrinking glass, but the more metal surface you have in contact with the glass the more likely you will get stress breakage.
You might try designing your piece with smaller amounts of metal in contact with the glass if it's important for you to fuse them together.
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Jackie Beckman
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Re: Making Itty Bitty Drop Molds?
Carla wrote:I'm a jeweler and want to make some very small 3/4" drop molds in various shapes.
I'm metal literate and since it is flat, cuts nicely I'm hoping I can make some outta silver, copper, or brass. I will kiln wash them before I put the glass on them. I choose these as I have them and tools that will shape them easily. Also I will probably use thin window glass, or maybe BE.
Is there any problems with this? Is the expansion/contraction difference between any of these metals such to make them unusable as a drop mold?
Thanks
Carla
Hi Carla,
My question about what you want to do does not pertain to the metals - you surely have a better understanding of them than I. However, I'd have to wonder if you would EVER get the glass to drop through a 3/4" hole?! That's the idea, right? If you use Bullseye glass, which is an 1/8" thick, you'll actually only have a 1/2" little hole, right? I've waited hours for what I'd call narrow drops - well, I would have called them narrow before - compaired to 3/4" they were enormous!
If you had a 10" hole in a drop and you were using a single layer of BE glass it, depending on your temp, it may take an hour to drop a couple inches. (heavier glass more quickly, naturally) Now if you dropped that same single layer through a 4" drop out, it's going to take substantially longer at the same temp. So if you have a single layer dropping through a 3/4" hole, you'll either be waiting days for it to drop, or you'll have to raise the temp so hight that you WILL end up with a melted metal mess.
I'm just not sure if what you are trying to do is possible. However, I could be wrong - not an expert. Maybe if you tell us what it is you're wanting to accomplish, we can help you come up with a better way to achieve it. Good - luck with your project either way -
Jackie
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Brad Walker
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I would tend to agree with Jackie. I would cast these shapes, not try to drop them through a ring. I have done that with holes as small as 1", but you need to very high temperature and a long soak. Even at that, you don't get much control and won't get the perfect shapes you're probably envisioning.
So just cast the glass, either using the lost wax process or by using a two part mold (female bottom, male top). When the casting is done, I'd add the desire metal as a separate step, rather than try to do it as an inclusion during the firing.
Aside from using an investment that can withstand the heat and having to anneal the glass, casting the glass isn't that different from traditional jewelry casting.
So just cast the glass, either using the lost wax process or by using a two part mold (female bottom, male top). When the casting is done, I'd add the desire metal as a separate step, rather than try to do it as an inclusion during the firing.
Aside from using an investment that can withstand the heat and having to anneal the glass, casting the glass isn't that different from traditional jewelry casting.
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charlie holden
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Experience from flower pot drips suggests a couple of things.
One is that you can find a ready made 3/4 inch hole in the bottom of a flower pot very easily. It's going to be in a pretty big flower pot though. You could kiln wash the bottom of the pot and drip your glass through, crashing the kiln when it dropped the distance you want.
I think Brad and Jackie are right though. I don't usually see drips coming through my flower pots until the temperature is up above 1500 F. The glass usually isn't in a vessel form either. It collects into a blob that hangs bellow the hole for a while before it drops. If you can do with elongated drip forms, like water drops from a faucet before they fall, then you can try soaking for a long time below 1500 F, watching carefully until the drip starts to move, and crashing quickly when it does. Once they start to go, they go quickly if the temperature is high.
About metal drop rings, they certainly work well on a large scale at least. I use 3 inch wide stainless rings with open diameters up to 25 inches. I think they contract more across the three inch solid ring width, (meaning that the metal may contract from 3.25 inches at a high temp to 3 inches at room temp.) than they do towards the center of the ring. So I haven't had any trouble with dropped bowls getting trapped inside them. I don't do steep walled vases though, so I can't comment about them.
ch
One is that you can find a ready made 3/4 inch hole in the bottom of a flower pot very easily. It's going to be in a pretty big flower pot though. You could kiln wash the bottom of the pot and drip your glass through, crashing the kiln when it dropped the distance you want.
I think Brad and Jackie are right though. I don't usually see drips coming through my flower pots until the temperature is up above 1500 F. The glass usually isn't in a vessel form either. It collects into a blob that hangs bellow the hole for a while before it drops. If you can do with elongated drip forms, like water drops from a faucet before they fall, then you can try soaking for a long time below 1500 F, watching carefully until the drip starts to move, and crashing quickly when it does. Once they start to go, they go quickly if the temperature is high.
About metal drop rings, they certainly work well on a large scale at least. I use 3 inch wide stainless rings with open diameters up to 25 inches. I think they contract more across the three inch solid ring width, (meaning that the metal may contract from 3.25 inches at a high temp to 3 inches at room temp.) than they do towards the center of the ring. So I haven't had any trouble with dropped bowls getting trapped inside them. I don't do steep walled vases though, so I can't comment about them.
ch
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Patty Gray
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Hi Carla, welcome to the BB.
If you wanted to make quite a few of these little shapes using a drop mold process, you could make a larger mold with with many of the size of holes needed, place the sheet of glass over the entire mold then do a slump. You will get each of the hole areas to drop and they should be uniform. Then all you would need to do is either cut or drill the slumped areas for your pieces, cold work or fire polish. Very simple process really.
Have fun,
Patty Gray
time4sun@worldnet.att.net
http://www.pattygray.com
If you wanted to make quite a few of these little shapes using a drop mold process, you could make a larger mold with with many of the size of holes needed, place the sheet of glass over the entire mold then do a slump. You will get each of the hole areas to drop and they should be uniform. Then all you would need to do is either cut or drill the slumped areas for your pieces, cold work or fire polish. Very simple process really.
Have fun,
Patty Gray
time4sun@worldnet.att.net
http://www.pattygray.com
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Carla
Wow. Lots of good info. And much for me to ponder while I work this out.
I really appreciate all your input. It's helpful. For those who requested more info as to what I am going for it follows. I will try my idea in brass later today and report back...when I have enuf info to be helpful.
More details if you want em:
Short version:
I want to make different shaped bubbles/hollow forms with the glass. So casting a solid shape is not an option-but a good idea.
Long version:
I want to make hollow, shallow bubble shapes so I can put things under them that will move around. Think of a watch face and how many of them are slightly concave. I put things like seeds, sand, small cabs under the glass. I only need about 3mm of clearance. There is a way one can do this using a complicated metal setting system which is time consuming. So if I could make little bubbles it would save time. I have tried this using kiln furnitures openings as the drop mold and it worked. But I want different/specific shapes. Since I am metal literate, my first choice for making a drop mold was metal as I can control the shape of the opening. My concern with fiber and clay is that they leave an impression as the glass turns the corner and starts to drop.
I have a picture/jpeg of what I am going for. When I figure out how to post it I will. It is a fish pin, Mama Fish, where I have set a flat piece of glass over the body and put little cabs under it. These cabs move around and look like fish eggs. I want to make more hollow formed pins, bracelets, pendants with things enclosed.
Thanks again for your input. I will now proceed to experimenting keeping in mind what you all have graciously shared.
Carla
foxon@bendnet.com
I really appreciate all your input. It's helpful. For those who requested more info as to what I am going for it follows. I will try my idea in brass later today and report back...when I have enuf info to be helpful.
More details if you want em:
Short version:
I want to make different shaped bubbles/hollow forms with the glass. So casting a solid shape is not an option-but a good idea.
Long version:
I want to make hollow, shallow bubble shapes so I can put things under them that will move around. Think of a watch face and how many of them are slightly concave. I put things like seeds, sand, small cabs under the glass. I only need about 3mm of clearance. There is a way one can do this using a complicated metal setting system which is time consuming. So if I could make little bubbles it would save time. I have tried this using kiln furnitures openings as the drop mold and it worked. But I want different/specific shapes. Since I am metal literate, my first choice for making a drop mold was metal as I can control the shape of the opening. My concern with fiber and clay is that they leave an impression as the glass turns the corner and starts to drop.
I have a picture/jpeg of what I am going for. When I figure out how to post it I will. It is a fish pin, Mama Fish, where I have set a flat piece of glass over the body and put little cabs under it. These cabs move around and look like fish eggs. I want to make more hollow formed pins, bracelets, pendants with things enclosed.
Thanks again for your input. I will now proceed to experimenting keeping in mind what you all have graciously shared.
Carla
foxon@bendnet.com
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Cynthia
Well I just visited your website. You have a quote there that seemed appropos for your experience with the bully.
"Beware of People who take themselves too seriously"
I think the person who harrassed you might be taking him/herself too seriously.
Very nice work. I particularly like the Halibut and Happy Fish (tons of character and soul...strong designs) and your Kanji pins. Can't wait to see what you do with glass. Here's wishing you success with this process you are working out. Can't wait to hear what you have to report.
Boron nitride is a nice separator for metals (stainless and copper anyway). If you don't like the kiln wash, you might want to consider BN.
"Beware of People who take themselves too seriously"
I think the person who harrassed you might be taking him/herself too seriously.
Very nice work. I particularly like the Halibut and Happy Fish (tons of character and soul...strong designs) and your Kanji pins. Can't wait to see what you do with glass. Here's wishing you success with this process you are working out. Can't wait to hear what you have to report.
Boron nitride is a nice separator for metals (stainless and copper anyway). If you don't like the kiln wash, you might want to consider BN.
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Tony Smith
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The Hobbyist
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Geri Comstock
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Hey, Carla!
Carla! Good to see you here!
Thinking about your question....when I was a kid, my mom had these "mini-muffin" tins that had openings that were really small...don't know how small, though. Anyway, if you could find one of those in stainless at a restaurant supply place, maybe you could use one of those as a drop mold. Just don't let the glass slump all the way down.
I don't know who said your question was stupid, but there are no stupid questions...only questions you ask because you don't know the answer to, and that's why you ask. Duh!
I know Carla in real life from the left coast show circuit...I had the honor of being her next door neighbor at a show in SF about a year ago. She and her husband kept me in giggles all weekend. We've had a few more giggles at shows since then.
It's good to see you here, Carla! See you in June for another show giggle fest. I think we're about 3 booths away from each other this time.
Geri
Thinking about your question....when I was a kid, my mom had these "mini-muffin" tins that had openings that were really small...don't know how small, though. Anyway, if you could find one of those in stainless at a restaurant supply place, maybe you could use one of those as a drop mold. Just don't let the glass slump all the way down.
I don't know who said your question was stupid, but there are no stupid questions...only questions you ask because you don't know the answer to, and that's why you ask. Duh!
I know Carla in real life from the left coast show circuit...I had the honor of being her next door neighbor at a show in SF about a year ago. She and her husband kept me in giggles all weekend. We've had a few more giggles at shows since then.
It's good to see you here, Carla! See you in June for another show giggle fest. I think we're about 3 booths away from each other this time.
Geri
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Barbara Muth
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Hi Carla. Welcome. I love your website.
You have an interesting problem. As I understand it, you want little domes without any texture on the glass. Am I right?
Two things occur to me. What if you slumped into a mold? If you create a mold with some indents in it, and the mold were plaster, and you slumped a thin piece of glass over the mold, if you had a smooth mold I think you could get a pretty smooth surface on the glass. Would you be able to polish the glass?
Let us know how things turn out!
Barbara
You have an interesting problem. As I understand it, you want little domes without any texture on the glass. Am I right?
Two things occur to me. What if you slumped into a mold? If you create a mold with some indents in it, and the mold were plaster, and you slumped a thin piece of glass over the mold, if you had a smooth mold I think you could get a pretty smooth surface on the glass. Would you be able to polish the glass?
Let us know how things turn out!
Barbara
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Joanne Owsley
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