John Forstall on thu 6 dec 01
I'm having a problem with slip flaking off rims of fired bisque. I'm using
Standard 130 porcelain. Slip is sprayed on leather hard ware and fired to
cone 04. Slip is made from 90% clay body plus 10% burnt umber, plus 2% RIO.
Anybody got suggestion for additive to prevent the problem? Thanks,
John
(John Forstall, Pensacola, FL.)
Carla Flati on sat 8 dec 01
John,
Rims are always drier than the rest of the pot even at
leather hard and I suspect this is the problem. The easiest thing you could
try is to just mist them with a spray bottle of water just before you apply
the slip. If you're having trouble with areas other than the rim, try
adding some Darvan 7 or sodium silicate. You won't have to add nearly as
much water to the slip to get it thin enough to spray as you would without
the deflocculant. Just make sure you really rinse out your spray gun
immediately afterward because the stuff gets a bit sticky. Hope this helps.
Carla
In Aliquippa, PA, thinking about how much I DON'T want to wash clothes
today!
Steve Mills on sun 9 dec 01
not necessarily so; if the slip is made of a material different in
character or shrinkage, particularly if it shrinks less it will spall
off the rim before it comes off anywhere else. I have found only two
materials that are reliable as a slip: one is the same body as you have
used, the other is an unusual ball clay which we get in the UK which I
have spoken about before called Hyplas 71 which fits anything!
Steve
Bath
UK
In message , Carla Flati writes
>John,
>
>Rims are always drier than the rest of the pot even at
>leather hard and I suspect this is the problem. The easiest thing you co=
>uld
>try is to just mist them with a spray bottle of water just before you app=
>ly
>the slip. If you're having trouble with areas other than the rim, try
>adding some Darvan 7 or sodium silicate. You won't have to add nearly as
>much water to the slip to get it thin enough to spray as you would withou=
>t
>the deflocculant. Just make sure you really rinse out your spray gun
>immediately afterward because the stuff gets a bit sticky. Hope this hel=
>ps.
>
>Carla
>In Aliquippa, PA, thinking about how much I DON'T want to wash clothes
>today!
--
Steve Mills
Bath
UK
Steve Mills on tue 11 dec 01
Dear All,
In a response yesterday on the above subject I trod heavily and
unthinkingly on the toes of the correspondent I was replying to. I wish
to make it known I am VERY sorry and wish to withdraw any inferences
made by my post.
--
Steve Mills
Bath
UK
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