WarmGlass.com

First I want to thank all who contribute so much knowledge to this forum, the information I have learned here and in Brads book is invaluable.

I am in the middle of a project and just had a thought--I fired my platter face down to keep the lines crisp, now I want to add a couple of decals--then I need to slump.

My process was going to be add the decals, fire to get my shine on the flipped piece. Then, slump into my mold. My question, if I add decals on the flipped platter before firing, will it shine up under the decal? Also, can I combine the decal firing and slumping or do these need to be two seperate firings. The platter or sushi tray is 5 x 11.

Thanks Carol

You cannot apply decals and then slump unless the decals are in an area that is not moving in the slump. Decals are quite thin and stretching them in the slump will ruin them.
This is one time that you need to use "glass" decals in the final step. They mature low enough that you can fuse them onto a slumped piece without ruining the piece.

Barry

Thanks Barry, didn't think of that part of it. But will the glass shine up under the decal if I add them to my flip and fire process?

Can I slump and fire polish my dish at the same time. Then add the decals and fire them while the dish is still in the slumper?

Carol

You can slump and firepolish together--just hold a little bit longer at the upper end of the slumping range. Watch it carefully--it's easy to overslump.

It'll give you a moderate firepolish that evens out the surface quality and glosses over any coldworked areas that are taken to 400-grit or so. It won't smooth over big defects the way a more intense fire-polish might.

Morganica wrote:You can slump and firepolish together--just hold a little bit longer at the upper end of the slumping range. Watch it carefully--it's easy to overslump.

It'll give you a moderate firepolish that evens out the surface quality and glosses over any coldworked areas that are taken to 400-grit or so. It won't smooth over big defects the way a more intense fire-polish might.

Just curious - What is "overslumped"?

There is no necessary concern about any layer of gloss but the top layer. The key to the answer of getting a gloss is the temperature needed to gloss the decal.

There are different sorts of decals. Vitreous decals are quite different from decals made with laser toner. Vitreous decals come in different temperature ranges to get a gloss, usually around 1050ºF or 1400ºF Metals and minerals do not stretch. If the glass stretches they will break apart. These include iridescent and dichroic coatings, gold and silver leaf or foils, micas, and the iron in laser decals. Glass, on the other hand does stretch. The effect of glasses stretching will be a thinning out of the color.

Over slumping means that the glass gets so much heatwork that the top edge of the slump begins to fall down and out of shape. When I enamel on float glass, I can get away with a 1400ºF slump firing that vitrifies the enamel. I do this routinely. However, Fusing glasses soften at a lower temperature, and may not be able to handle that high a temperature. Some kilns will create more heatwork getting to 1400ºF, than others.

So, if your decal is in the 1400 range, and if your glass and mold will play well at 1400, you can get the job done in one firing. However if 1400 is too hot for the slump, you will need to do both decal and slump firings. If your decal is 1050ºF, you can do it all in a slump firing, but you will have to worry about the colors burning out at your slump temperature. Some colors are more stable than others. I have never done any work with laser print decals, so I don't know what temperature they require to stick. They will not gloss, without an overglaze.

Thanks everyone. I fire polished with the decals on last night and was happy with the results. Looks like they fired just fine--now I am slumping and hoping for the best. This is a shallow slump so the temp and time are not extreme and it doesnt look like the decals are in an area that will be stretched to much. This is a gift for my sister-in-law who I will see tomorrow. Next time I will think a little longer on the sequence of how I will approach this.

Carol