enamels at fusing temperatures

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Michele-MD
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enamels at fusing temperatures

Post by Michele-MD »

Hello, I've been reading lots of the history on the board regarding enamels and their uses and am grateful for all the information that is here. But, I still have some questions. I want to put enamels between layers and fire to full fuse temps for BE glass, so at least 1450 F or so. I would like translucency or some degree of transparency so that I can have layered effects. I have some Reusche "5" series and have just ordered the Ferro Sunshine enamels from Brad. I also have some Color Line and Glassline that I have acquired over the years. There are even some Thompson powders somewhere in my studio. I thought that by using very thin/dilute? layers I can get some translucency but am not really sure and wonder whether there are better choices than what I have to do this. I am about to start experimenting but thought it also worth asking the painting gurus. I have a feeling that there is a fundamental rule about how the paints are formulated that governs their use that I might be missing. Also, I read that the Thompson enamels are quite coarse compared to others, more like glass powder, and wanted to know if they could be made finer by mulling? And finally, I also read that by adding flux I could change the temperature at which some paint colors mature. I would really like to understand what adding the flux does and whether it is also a way to dilute the paints to get translucency? Many thanks for any insight you can share.
Michele
Terry Gallentine
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Re: enamels at fusing temperatures

Post by Terry Gallentine »

I use fluxes all the time. I don't mix them with premade enamels though (usually). I mix them with ceramic stains in different percentages depending on the level of transparency I need. The ceramic stains are very fine as is the flux that I use (it is a grade called "water ground"). I have not sandwiched these between glass layers but I would imagine you would simply need to get a higher temperature flux. I use an 1100 degree flux which when mixed with the ceramic stains matures at around 1300 degrees.
Michele-MD
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Re: enamels at fusing temperatures

Post by Michele-MD »

Can the ceramic stains that you are using be used at full fuse temperatures?
Michele
Terry Gallentine
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Re: enamels at fusing temperatures

Post by Terry Gallentine »

They will handle full fuse temperatures since they were primarily developed for pottery but I have found that they need to be mixed with something (flux or powdered glass) or they will not have enough plasticity to stay together as the glass under them becomes more fluid.
Bert Weiss
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Re: enamels at fusing temperatures

Post by Bert Weiss »

Of course it's complicated. Onglaze colors are a mixture of clear frit and metallic oxide colors. Blue is transparent, the rest of the colors are not. White is the most opaque. They are translucent and will glow nicely with moderate back lighting. If the back lighting is too strong, they look much worse, not better. If you want a truly opaque coating, you are best off mixing white in.

I routinely encase Sunshine colors working with float glass. I am relatively careful not to make a lumpy deposit of paint, as these will surely create bubble gaps. I prefire the painting to 1080ºF. This works perfectly on float glass, as it does not begin to bend until 1100ºF. 1080 is hot enough to make the colors stick to the base glass, without allowing it to bend. It is just barely tack fused. Then I cover and fuse. My basic glass is 10mm thick. This is a huge advantage to me, because gravity really helps to eliminate bubbles. Lighter glass would be much more difficult to achieve a good bubble squeeze firing.

If I were working on softer fusing glasses, I would find some lead bearing flux that softens at a temperature below where the glass will start to bend, and do the same. I would fire to 1000ºF. Fluxes designed to gloss at 1250 will tack fuse at 1000. You can use either colored enamel or clear flux, you have to learn what happens to each color when over fired in the final step.

One big lesson I learned is that putting less paint on achieves the same look as mixing clear flux in. It is basically a waste of flux to use it to thin down a color.

Here is a picture of a 30mm thick bartop. The color is painted on the second surface from the bottom. Lighting, of course, is above the glass. ImageImage
Bert

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Michele-MD
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Re: enamels at fusing temperatures

Post by Michele-MD »

Bert,

That is gorgeous. So glad you posted the closeup of the surface. Translucency is exactly what I am looking for. I want depth of visually overlapping colors that are on different surfaces. I had not considered working on float, but could certainly do that. Can you please tell me what is the significance of using "onglaze" colors and also why it is important to you to be working below where the glass softens and moves? I could understand if you were panting an image and didn't want distortion but is there something else? I would like to avoid working with lead as much as possible and thought using "high fire" colors would do that. But the glass certainly is moving at those temps.

I am ok with complicated as long as the info is there to understand and I can get some idea of what is going on and why. That's the part of glass that keeps me interested. Thanks for your help.

Michele
Bert Weiss
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Re: enamels at fusing temperatures

Post by Bert Weiss »

Michele-MD wrote:Bert,

That is gorgeous. So glad you posted the closeup of the surface. Translucency is exactly what I am looking for. I want depth of visually overlapping colors that are on different surfaces. I had not considered working on float, but could certainly do that. Can you please tell me what is the significance of using "onglaze" colors and also why it is important to you to be working below where the glass softens and moves? I could understand if you were panting an image and didn't want distortion but is there something else? I would like to avoid working with lead as much as possible and thought using "high fire" colors would do that. But the glass certainly is moving at those temps.

I am ok with complicated as long as the info is there to understand and I can get some idea of what is going on and why. That's the part of glass that keeps me interested. Thanks for your help.

Michele
Michele. I want the glass to be flat when I fuse it, in order to minimize bubbles. So, when I prefire it, I keep it from bending. The significance of onlglaze colors is that they both gloss, and retain their color intensity, in the fusing temperature range. Colors designed specifically for glass have always been about either decorating glassware, or bending colors for use on items like light fixtures. Onglaze means that there is clear glass frit in the colors that glosses on the surface. Underglaze colors do not have this component.

If you routinely fire multiple layers of fusing glasses, and then fuse them, there are no further issues. I do find that I need to burn out the organics from my medium and binders before casing and fusing, especially on large areas. The smaller the area, the more likely you might get away skipping that step. Some media seem more friendly to burning out cleanly during a fuse firing, but I have encountered problems even with CMC, which some people reported using with success. So, I prefire.

If I wanted to prefire fusing glasses, I would use some (probably lead bearing) low temperature flux mixed in with my onglaze colors. That would serve as a matrix to hold all the powder in place between prefiring and fuse firing. Flux is just a word for clear glass frit with a lower softening temperature.

I discovered that there are really cheap frits, and really expensive ones. The expensive ones are made in small batches and are very finely ground. The cheap ones, the opposite. The beauty of working with these powdered materials is that the application of glass is so thin, that compatibility is generally not an issue. If you were to pile them up, that would change.

If you work with float glass, you have to deal with the effects of the tin side. There are colors that are ruined, like turquoise, and colors that are browned, like cobalt blue. and colors with no visible effect. You have to test. The one hard fast rule I have is to always fire a stack with a tin side on the bottom. The tin protects the glass surface from getting rough. The other rule is, if I am going to slump, never have the top layer be tin. Consequently, I tend to work with colors that come out OK, in contact with tin. The countertop is 3 layers thick, and with color only contacting 2 surfaces, both of which were air sides. Chances are, I put the air side up for the top layer, but it wouldn't really matter on a flat piece.
Last edited by Bert Weiss on Fri Apr 03, 2015 11:14 am, edited 1 time in total.
Bert

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Bert Weiss
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Re: enamels at fusing temperatures

Post by Bert Weiss »

BTW, Sunshine series colors contain both lead and cadmium. They are designed for use on dinnerware, so when applied and fired, as designed, they will not release more than allowable amounts of these elements. There are other series, without these ingredients, but they require a little higher temperature, and the colors are not as vibrant, in general.
Bert

Bert Weiss Art Glass*
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Furniture Lighting Sculpture Tableware
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