Hi Glsela,  can you tell us what number thompson enamel you are using and in which order.  thanks 

Hi Martin,

thanks for picking this up. I use Thompson liquid form 303 L (medium fusing clear Base Coat) and 969 A (low fusing fusing clear Base Coat). I used them so far only by themselves not in combination. It is the first time I'm trying liquid enamels. With the regular transparent enamels I never had problems getting them clear. It seems to me that there are  a lot of variables where things can go wrong.

Thanks Gisela

I don't know anything about copper, but the order of the enamel doesn't matter. The only order that matters is the final color you want to end up with. Remember transparent enamels mix with the previous fired enamel color. If you not careful you will end up with a totally different color than you wanted. Use a color chart if you not sure of color mixing. The lighter the application, the more transparent the color will be, but evaporation will occur at a greater rate. Once evaporation starts you will lose the project.  

I am not an expert, but from reading I think that some transparent clear enamels become more clear only after firing very hot.  Maybe the copper oxide dissolves into the glass at the high temp?  Cleaning the metal just prior to enameling would reduce oxide.  If you have a thin piece of fine silver you could run the same recipes on that to see the difference.  

I have used the liquid form white as a base before because it is easy to use.  I should keep better notes.  If I remember correctly I used the 1070 white and that comes dry to mix or wet in a jar, and has a ceramic glaze type feel to it.  

When it is dry you can scratch it off with a pointy tool.  If the clear liquid works like that you could scratch down to bare metal then fire, then re-coat over the firescale to get a 2 tone, or etch to get cut into the metal.  

I think that maybe some people put down foil below their transparent colors to keep the lower enamel from contaminating.  

An overall strategy that I have read about several times is to use a higher temp base coat fired at a high temp first, followed by secondary coats fired at lower temps, with the last fire hot enough to meld the piece.

the thompson 533 is another white liquid.  Maybe that one has a different temp or expansion rate, because on their site they say you can put it over lower expansion enamels to get a crackle effect. 

are you using 36 gauge c110 foil?  

Have a nice day  marty 

I use 22 gage cold rolled steel.  I have an article I have written for Glass on Metal on cleaning steel, which will work for all metals, and applying a ground coat. I have photos showing my entire process. This process eliminates annealing and sparex.  Cleaning all metals properly prier to ground coating is essential for a perfect base. The article is supposed to be out next month. Without a good ground coat the rest of your project is a flip of the coin to weather you project is flawless or has problems. Ground coats are fired at 1500 degrees, your following coats are usually fired from 1300-1350 degrees. I don't use copper or foil, though I am going to start experimenting with copper in the next few month. Charles  

Many thanks to both of you - Martin and Charles, taking the time to answer to my question in such a detailed way. Unfortunately there was nothing I hadn't tried already. 

However my chemist soul didn't let this rest. I've a some ideas what the issue is but I'm testing a few more things and when I can repeat what I do I will report here. It may help others when they start to use liquid enamels.

Gisela  

Gisela, I'm a beginner, too, but love learning about enameling. I found an article online written by Thompson Enamel's Woodrow Carpenter on liquid enamels http://www.ganoksin.com/borisat/nenam/liquid-enamels.htm . If I've read this correctly, the liquid form enamels are the "industrial enamels" he's writing about and they contain very fine enamel powder plus clay. This might explain why the "transparent" liquid form enamels don't get as clear as the 80 mesh enamels! That certainly has been my experience. Those with more experience, please correct me if this is wrong!

Many thanks Candy for the link o the article. It was very helpful.

In the meantime i figured that part of my issue is expectation management. You are right, liquid enamel is not as clear as the leaded enamels I am used to for about 30 years. But it is nice to learn new things. I'm doing some tests and eventually I will figure out what I can do with which liquid enamel.

Gisela

You're  welcome, Gisela. Learning what to expect is important but I do love surprises. Good or bad, I learn something new.

Here comes the promised report on experiences testing Thompson clear liquid enamels (969 A and 303L) in my studio setting. May be this can help others new to liquid enamels.

First of all it was an issue of expecting too much. I remembered a photo of 303L in a back issue of glass on metal, here the enamel also did not reach the clearness of the leaded flux I'm used to. And secondly I tried to enamel little bowls  made out of corrugated copper foil (0,1 mm) by brushing the enamel on (I don't have airbrush equipment). Here the differences between peaks and valleys was too much, the enamel in the valleys was too thick and at the peaks too thin, either becoming not clear or burning out. So I made tests on flat sheets.

Here are the results I found in my setting: I fired at 840 degree celsius, less then 3 min as the pieces were quite small. Both medium and low fusing clears have a different ability to solve copper oxide compared to leaded flux. Medium fusing clear (303L) solves the oxides more less with green tones, were as  low fusing clear (969A) results in a brownish color. If the clear was too thin and burned out neither 303L nor 969A were able to solve the black layer. However when I used leaded flux the black layer was dissolved into a beautiful red. Leaded blue and green fired over a not totally clear 303L resulted in nice clear colors. In the mean time I can control the results. I attach a photo of 5 little pieces which will be framed each in a black frame. Now I understand the properties of the 2 liquid clears better and can consider their specific properties in my design.

Thanks again to all who responded to my original question.

Gisela

Hi members of Grains of Glass,

I'm new to using liquid enamel. I'm using Thompson liquid enamels on copper (foil) and I have difficulties getting a clear transparent coat of medium fusing clear as well as low fusion clear. I would appreciate to get tips what I might be doing wrong.

Firing too high, too low, too long, too short.......?

Thanks  in advance

Gisela