How to make perfect oval cabochons like from Etsy

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muffin
Posts: 2
Joined: Fri Jan 09, 2015 1:18 pm

How to make perfect oval cabochons like from Etsy

Post by muffin »

Hello,

I'm a newbie in jewelry making and glass fusing. I've been playing around with some of the 30x40mm oval cabochons from Etsy but I don't like the domed shape. I'd like to make my owns, but I don't get anywhere close to them :(
If I cut a diamond shape, I can't control how the glass flows too well and they just end up not fitting anyhow. I think working with a cast and glass frits might work best, but I haven't found anything helpful about it yet. Any ideas? How are the guys on Etsy making these perfect cabochons that are perfectly alike and fitting to the millimetre? They must be cast or not?

Thanks and best regards,
a desperate newbie
Jenna
Posts: 46
Joined: Mon May 21, 2012 10:34 am

Re: How to make perfect oval cabochons like from Etsy

Post by Jenna »

Can you be more specific about which cabochons you mean? There are so many on etsy, some handmade, some mass produced. You mention you don't like the doming, but you may find that even if you make your own in a mold, you will end up with some doming yourself. Tthis is due to the nature of the glass' surface tension. Think of a water drop, which is always somewhat domed unless you add something to the water to break the surface tension.
muffin
Posts: 2
Joined: Fri Jan 09, 2015 1:18 pm

Re: How to make perfect oval cabochons like from Etsy

Post by muffin »

Hi Jenna,

thank you very much for your answer. I am refering to the perfectly uniform clear oval cabochons from Etsy. Yes, I know about the doming, however, I'd be grateful if I could get a little less of it.. So far, I found out you can buy a glass cutting machine, cut ovals and "fire polish" the rough edges by heating it up to a certain degree. This would probably the best option for me.
Jenna
Posts: 46
Joined: Mon May 21, 2012 10:34 am

Re: How to make perfect oval cabochons like from Etsy

Post by Jenna »

Cutting your own might be the way to go. Seems like a lot of work when cabs are so inexpensive. What kind of a machine? A ring saw or a lens cutter? Or something else entirely? Do you need your ovals to be perfectly clear? Just thinking that your glass MAY pick up a small amount of texture from your kiln shelf during the fire polish. Not sure about that last point.
Morganica
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Location: Portland, OR
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Re: How to make perfect oval cabochons like from Etsy

Post by Morganica »

Are you sure you want cabochons? Cabochons, almost by definition, are pretty domed. Are you just looking for flat ovals of glass? If you can post pictures of what you want, top and profile views, it'll be easier to tell you how to achieve it.

Basically, cold shaping trades off with hot in glasswork: The more of one you do, the less you have to do of the other. The "doming" happens because the glass becomes soft and flowing when it's been given enough heat in the kiln that it starts to flow, and surface tension starts trying to turn it into a sphere (think about what happens when wax get hot enough to flow, or when water beads up on a freshly waxed car).

So, if you can cut near-perfect ovals and get the edges practically smooth, it will take very little time/heat in the kiln to smooth them over and make them uniform, and you won't get the doming. The hard part there, usually, is getting them all exactly the same shape and size. Conversely, you can cut a sheet of glass up into rectangles, exactly the same size and shape, and nuke 'em in the kiln. All that heat will cause the rectangles to draw up into ovals, and (as long as they're getting the same heat levels), they'll have the same dimensions...but they will all be domed.
Cynthia Morgan
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http://www.morganica.com/bloggery
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