Karl P. Platt on fri 4 oct 96
Joe --
You must be living right. I'm sitting here chartreuse with envy? Free
Zirmuls? Free Tamuls? Have you priced these? No way! Do they have any
more??? I'll buy 'em.
These brick are usually found happily serving as glass tank paving.
Zirmul, as the name suggests, is ZrO2 in a mullite brick. You've
probably noticed that they're very heavy.
These things do not do cyclical heating well at all as a result of the
zircon, which undergoes changes similar to those seen in quartz, but it
occurs at much higher temperatures and can be of substantially larger
magnitude. I would expect either of these bricks to deteriorate in a
ceramic kiln in a fairly short time as a result of thermal cycling.
Tamul is similar to Zirmul, but I notice my North American Refractories
catalogue isn't here on the shelf, so I lack specifics. North American
or Didier Taylor has an office in Ohio -- either Cinci or Portsmouth.
They could fax you details.
I built this little melter here for making colored Pyrex. When running
it is constantly above 2,700 :F and while melting sees sustained
temperatures above 3,000 :F for periods in excess of 8 hours -- Pyrex is
a bitch to melt well. In this furnace the walls above the glass are made
of Tamuls and they look now as good as they did when they were put in --
whereas the 90+% Al2O3 Korundal brick right next to it slumped under the
heat. When melting Pyrex one really learns the true limits of
refractories, and maybe some of the things we saw are another post.
Suffice it to say these are very serious refractories. However, in the
potmouth (door) of the furnace I placed a Tamul split to keep glass from
getting in between the bricks below. This brick died as a consequence of
thermal shock -- cracked, split, etc. I had to chisel it out just a few
days ago while doing maintenance for the next campaign.
I suppose you could use them to build a really nice little frit tank.
This has wonderful possibilities.
Regards,
Karl -- shaking his head in disbelief.
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