Chipping Concave Glass

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Posted by Bruce Jackson on March 05, 2004

I've got a project going that will use glue chipping for the letters. The glass panel is oval shaped and is also going to be slumped to a gentle concave.
I'm planning on chipping first, then slumping. Mainly because I'm concerned the glue will pool if it is slumped first.

For those unfamiliar with slumping glass, the temperature is low enough that it doesn't affect surface texture.

Any comments?

Raymond Chapman

Jeff Cahill was glue chipping one of Rick's curved glass pieces at the Waco Letterheads. He just poured in the glue and gently tilted it in several directions so that the glue dried at a somewhat consistent even depth. It chipped great.

I also have one of those oval glass pieces from Rick and hope to do something with it someday. Still looking for that round tuit.

Danny Baronian

I think the biggest concern would be the size of the letters. If there large enough, there shouldn't be a problem.

I think the ovals Mike refers to were the glass vanity sinks Rick chipped. He would mix the glue 1:1 with water to make a thicker glue so it wouldn't run. He also used the same mixture on a 1 gallon mason jar, the one in the photo.

I would think you'd want to do the chipping after the slumping. Doesn't slumping involve putting the glass in a kiln until the glass is heated in order to slump into the mold? If so, it seems it would affect any chipping done prior to slumping.

Danny

Bruce Jackson

The slumping will be just enough to curve the glass. The surface doesn't actually touch a mold.
We will support the glass on an oval-shaped ring which allows the glass to bend as it heats. If we use a low temp program on the kiln, we can stop it at the right moment before it slumps too far.
I have a stained glass artist friend who will do this bit for me. He's got the equipment and expertise.

Thanks for the other comments too Raymond and Mike.

I will try doing it both ways and let you know the pros and cons of either slumping or chipping first.

Mike Jackson

Bruce,
I think you "can" do the chipping after the slumping. Rick used to sell the large ovals with the slumped shape. The hard part would be using computer cut masks or stencils, so most of the work would have to be done by hand. You could use the asphaltum method and "squirt" glue onto one or two letters at a time and as the glue gelled, I don't think you would have problems with it pooling or being any thicker due to gravity.

Even if you squeegeed the glue, you could cool the glass and work in smaller sections--opposite of the normal process where you want the glass to be as warm as possible so you have time to even the glue out before it started to gel.

Keep us informed on the progress or what you find out!

Mike

[Jeff Lang]

I have recently done a project on a curved piece of glass. I used the 1:1 by volume water to glue ratio on glass that was blasted with 80 grit siliconcarbide & it worked very well. I applied the glue to each letter, allow the glue to gel, & it only took a minute, for the glue was a bit thicker, then tilted the glass to do the next letter.
Jeff

[Danny Baronian]

Great Jeff,

Now where's the pictures?

[Danny Baronian]

Great Jeff,

Now where's the pictures?