Ron Roy on mon 8 oct 01
One of the issues here is the difference in the expansion/contraction
between the coating and the brick. It is the reason the salt is so hard on
brick - Na2O has the highest expansion of all the oxides we use - take a
close look at any salt glazed pot and you will see the crazing.
The expansion of this glaze is neither low or high but even that will not
be a guarantee the coating will stay put.
One of the biggest problems to overcome with high fired soft or hard brick
is the build up of cristobalite - every time the kiln is fired more
cristobalite forms. Cristobalite increases the expansion and contraction of
clay (bricks) and any glaze coating will not stop it. There comes a point
where the glaze/clay bond is going to give up.
I can see how this might work on shelves - different animal than bricks - I
would tread carefully here and do some long term testing to see what will
happen.
RR
> How about glazing the bricks with my old 70's Oatmeal glaze
>Whiting 300
>dolomite 1050
>talc 1050
>feldspar 2025
>Nep syn 1275
>EPK 1500
>Flint 300
>Zircopax 750
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
Jim V Brooks on mon 8 oct 01
It may not be a good idea to use them as Ron Roy states.. However, you
can sometimes get glazed brick at brick yards for reduced prices.
Occasionally, the gas provider does not get the salt water filtered out of
the gas and the results is a load of glazed brick. Glazed brick are useless
to the brick yards/companies and are thrown away.. .or crushed for grog. SO
if this is what you want..make a phone call or two.. Jim in Denton
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