WarmGlass.com

Hello - I am airbrushing with Bullseye Color Line and getting some great results! Occasionally, on the second firing I am getting "veining" on the entire piece. It's really a rather pretty pattern, but not on these pieces. I'm using 90 Bullseye. Do the Color Line products need a slower firing schedule or need to be tack fused first? Seems like I read that somewhere and now can't find it! Any help would be appreciated!

In my test samples, thicker applications would tend to crackle a bit.
How fast/hot are you firing?

Here are the instructions:
http://www.colorlinepaints.com/pdf/colo ... let-en.pdf

Thanks for the quick response. That site has the red "Warning" about safety. Thoughts on that?

Linda, I'm not sure what you mean. When I click on that link, it takes me to Colorline's pdf instruction book. If the link is giving you a warning, you may just want to do a Google search for their site.

Valerie,
The warnings are in the lab notes toward the bottom of the PDF.
I copied and pasted them here for you:

The red in vitreous products is known for its special character. It has always been difficult to make a consistent red glass,
those who mastered it tended to keep it secret.
Color Line offers 3 brilliant reds – 125 Carmine, 011 Red and 074 Lacquer Red – which luckily are easy to use and behave
much less capriciously than many other red enamels, however, there are few things to note:
1. Out of all Color Line products, Carmine, Red and Lacquer Red are the brightest in expression and shade. They are also
the most difficult to get off your fingers and clothes. If you want to be on the safe side, wear old clothes and gloves
when you work with these colours.
2. Even though the pigmentation appears and in fact is very strong, you need to use a good amount of paint to have a
strong registration after firing, this is especially true when you airbrush the colour.
3. All Color Line Paints are freely mixable – including the reds. However, some mixes end up as a brownish/greyish
shade after firing – looking very different from the unfired product. To be sure of your colour when mixing reds, we
advise you to run some tests prior to working on a larger project.
4. We have discovered that trying to obtain a light pink when mixing red and white is tricky. Based on the problems
mentioned under point 2 the red colour tends to burn out, leaving you with the white only. In our testing we found
that a ratio of 1 part red and 6 parts Mix White 129 resulted in a pleasant pink.
5. Reds like to be fired alone, i.e. fire the other colours before and add the red in a further separate firing. This is
recommended to avoid too much medium being burnt off in the presence of red. When the medium in the paints
burns off, oxygen is consumed and creates a reductive atmosphere in the kiln, which can influence the red colours.
6. Finally, (and this is the solution to many firing problems), keep the kiln vent holes open during the firing. Especially
the reds do not like the slightly reductive (oxygen poor) atmosphere you tend to have in any firing. By leaving the vent
holes open, or the door slightly ajar, the kiln will draw in oxygen from outside and guarantee a neutral atmosphere
and a stable and brilliant red.

Thanks for that, Carol! Obviously, I misunderstood.

I always fire my kilns with the peep holes open during the entire firing, so haven't noticed any difference with the reds. I haven't worked with Colorline extensively, though.

Here's my test piece:

Yes, I saw you post that some time ago, after they came out. I helped do some testing of them for BE and found the red cracked and burned regardless of how careful I was with it. Thin, thick, it didn't matter. I have to say though, I liked the burned color (but that's probably just me) and the red hue when it stayed red.