I have just started doing some enamelling, and I have a question about counter enamelling. I read all 4 of the books on enamelling in the library, and I 'm sure I read somwhere that if the pieice is over 1.2mm thick or domed you dont necessarily need to do it. I have made a few pieces from 1.5mm copper which seem to be fine only enamelled on one side.

But I have having difficulty with some domed bronze I am trying to champleve enamel.
I did a couple of pieces which were slightly curved on the edges or a very shallow dome , they were fine. I dont however know anything about the enamel used for those, it was some anymous stuff given to be years ago by someone having a clearout. I then tried to do dome with a more pronounced dome (think largest cicle in doming block) the middle of one piece is fine but the edges keep cracking . This is using WG balls enamels I have tried using with and without flux as a bottom coat. The other piece which has a more solid metal edge is cracking out in the niddle.

Do you think if I counter enamelled the back it would help? I dont really want to as I like the bronze finish, they are made out of old pennys and you can just about tell this if you look closely at the back. Is the problem the doming , is it ok with a shallow cuve as opposed to an actal dome?

Any advice welcome