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pinholes and cmc

updated fri 10 feb 12

 

Maggie Furtak on thu 9 feb 12


Hey Carl,=3DA0=3D0A=3D0AGood topic! =3DA0I'm with Lee, I'm a sponger. =3DA0=
I figure i=3D
t gives me a last chance to wipe off any residual clay dust or greasy finge=
=3D
rprints that might cause a glaze crawl. =3DA0=3D0A=3D0AI'm also a fan of a =
handfu=3D
l of Epsom Salts to every five gallons of glaze to help with glaze suspensi=
=3D
on. =3DA0Easy peasy lemon squeezy. =3DA0It dissolves very nicely, unlike be=
nton=3D
ite and CMC, which, as you mentioned, can give you a big lump in the glaze =
=3D
bucket unless you are careful about how you add them. =3DA0=3D0A=3D0AAnd no=
w the =3D
big question... =3DA0Where are your pinholes? =3DA0Just where two glazes ov=
erla=3D
p? =3DA0(Glaze is becoming too thick at that point due to the overlap or th=
e =3D
glazes don't play nicely together). =3DA0In the bottoms inside of mugs and =
bo=3D
wls where glaze is pooling and ending up very thick? =3DA0All over? =3DA0(A=
djus=3D
t your bisque temp, your glaze temp, or your glaze recipe). =3DA0Just aroun=
d =3D
the foot where you have trimmed and roughed up the clay? =3DA0(I like to ma=
ke=3D
a final pass with a rib or some such to smooth the clay back down after I =
=3D
trim and push the exposed grog back under the clay surface). =3DA0Only pots=
o=3D
n the bottom shelf of the kiln? =3DA0(Bottom shelf may be a little under-fi=
re=3D
d). =3DA0Only on the top shelf of the kiln? =3DA0(Top shelf may be a little=
ove=3D
r-fired). =3DA0Only the firing that took forever to get to temperature? =3D=
A0On=3D
ly the firing that went very quickly because there wasn't much in the kiln?=
=3D
=3DA0(Put more in the kiln, or add a hold towards the end of your firing
cycle). =3DA0Can you see pinholes immediately after dipping your glaze, or=
o=3D
nly in the fired piece? =3DA0(If the lid to your glaze bucket doesn't have =
an=3D
airtight seal, maybe a little water has evaporated from your glaze and it'=
=3D
s just going on a tidge too thickly). =3DA0So many possibilities...=3D0A=3D=
0APut =3D
on your mad scientist hat!=3DA0=3D0AMaggie Furtak=3D0A=3DA0=3D0APate Cerami=
cs=3D0Apatec=3D
eramics.etsy.com=3D0Apateceramics.blogspot.com=3D0A781-956-1364=3D0A517 Fel=
lsway =3D
East=3D0AMalden, MA 02148