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how do i repair bisque cracks

updated wed 15 may 02

 

Jeff Tsai on tue 14 may 02


Well, what you propose might work, but the b-mix will simply shrink againand
the crack will not totally fill. But you say this will be okay because it
will just take a few firings...well, why not make the thing again. If it
isn't a super-complex teapot with the colliseum carved into the side, to
scale of course, you can probably remake it in the time it would take to
rebisque a few times.

However, this is a great learning experience, and for shame to your teacher
if he or she doesn't let you explore it. I would try this...I filled a crack
doing this and it worked in one fire.

Take some bee-mix and dry it real fast (flatten it and sit it in the sun).
once it is bone dry, crush it into a powder, put it into a previously
bisqued
bowl and bisque the powder. (make sure you have enough to fill the crack)

once it is bisqued, the powder may have clumped a little again, but it
should
be easily breakable...you just made a fairly simple kind of grog out of the
same clay your teapot is made of. Mix this grog together with a very small
amount of dry, unbisqued clay, add some vinegar, and patch the hole.

The breakdown of this patching recipe that I recently used to some wonderful
success was simple:

3 parts grog
1 part clay
add some vinegar and there you go.

(I also put a little bit of Duncan underglazes "patch attach" which is, I
think, mostly glue, fine grog, and clay) but you probably don't need it. try
doing this, see if it works...if not, well, while you are re-bisquing, throw
another teapot.

-jeff