Craters Appearing After Decal Firing

[rissierae]

Recently I've been having craters appear after a decal firing that weren't there after the glaze firing.  Basically, the piece comes out of the ^6 glaze firing just fine, I put the decal on, fire it, and there are craters!  I only have one guess as to why this would happen, sometimes I bisque fire in a decal firing because they can go to the same temp. (trying to be efficient and all).  Could the gases that the greenware is giving off, cause craters in other pots?

[neilestrick]

Pictures, please.

[Marcia Selsor]

When I made decals in the 70s I used a china paint type of ink and fired much lower. I don't know what decals you are using but I think you are guessing correctly. It could be the atmosphere from the bisque.Try firing them alone and see what happens. also leave the lid open for a good couple of hours while the decal medium burns off.

 

Marcia

[Mark C.]

I suggest only firing your decals and not bisquing at the same time.

[bciskepottery]

When you refired your wares for the decals (and also ran bisque), you heated the glazes up just enough to start melting . . . and went into cooling that froze the craters.  Decals can be fired at a much lower temperature than bisque -- some recommend cone 017 to 012 or so -- which is just enough to fuse the decal into the glaze without affecting the overall glaze.  As suggested, do not combine the loads, fire them separately. 

[Mark C.]

All my past decals where in that 017-012 range not bisque range. I think as Bruce said in above post you have over fired them.

There seems to be a lot of crater posts lately -Nerd may chime in on this

On a more fun note check out the Halema'uma'u crater next time you are on the Big Island of Hawaii its got fluid  lava in it now and and the fern forest is a great hike.If thats to far away check out metro crater in central Az-I hiked it when I was 12. These craters are more fun than pottery craters which can be easily fixed with a a hammer-

[rissierae]

Thanks for the advice.  I will be bisqueing separately from now on.  I really think that's it.  The batch I did before these didn't have any problems, and I wasn't bisqueing at the same time. 

 

I'm pretty sure these decals need to go to ^04 to be permanent.  I'll check Justin Rothshank's website to be sure, but I've been making these for years, and haven't run into too many issues!  Not this one anyway!

[Marcia Selsor]

Good to know you solved the problem. The firing temperature would simply depend on what type of ink base you're using. Marcia

[Pugaboo]

If she is using the Justin Rothshank website chances are she is using laser Transfers. I do TONS of pieces with laser transfers.

 

I fire mine to cone 05 if alone or I put them into a 04 bisque load. When I do with bisque I put them on the cooler shelves and have never had an issue with craters and such. Have you used this particular glaze before with the Transfers? If so is it a new batch of glaze or has anything else changed? Have you ordered new transfer paper or changed the printer you are using to print the Transfers.

 

I do know some glazes can change color and not to the good all the time so testing will need to be done to figure out just what is going on in the kiln. Some glazes will make the Transfers come out more Orange or even fade away. I would suggest test tiles with a few different glazes, test tiles at different temperatures, different firing schedules, if you have some older Transfers put them on a piece and fire it and see what happens, etc. Basically you are trying to isolate and the eliminate whatever has changed, think back to your last successful transfer firing and think on what might have changed around that time.

 

T

[rissierae]

Yes, laser transfers.  I have used this glaze with the transfers several times.  I did some testing with it first, and thought it was fine.  I did a large batch of mugs that didn't have any issues.  I can't think of anything else I have done different.  I guess I'll have to take a step back, and maybe do some more testing.