Hi Sheridan. I'll address your response one item at a time.
1) It isnt the Hardness or softness of the enamel that causes
problems. It is their COE (coefficent of expansion )rates. Hardness
and softness, and COE's are two different things. If you are working
with Thompson enamels you can check with Thompson to find out the COE
for each of the enamels you are working with. In fact, if you do not
already have it, get their Workbook. It costs about $10.00 and is an
invaluable source of
2). 24 gauge is very thin. for a triangle of 1" I use 18 gauge.
3). I avoid sterling, as even if you bring the fine silver to the
surface before beginning to enamel, you usually run into problems
around the 3rdor 4th firing. I much prefer fine silver to sterling,
as one does not have discoloration problems. Sometimes I use copper
covered with gold, or silver foil--depending on what I am making.
4). Regarding the flux you used as the final layer---- it may have
had a COE lower than that of the enamel below it.
Also,remember that the thickness of the counterenamel on the back
shouldbe equal to the amount of enamel you are applying to the face
of your piece.
To sum up, I would suggest you use a heavier gauge metal, and watch
those expansion rates, and the thickness of the counterenamel. Hope