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Posted by Cee White on February 5, 2007, 2:49 am
Please log in for more thread options Going back a few decades, I bought a couple huge old platters at an
auction. They were badly crazed, cost near nothing. I fired them in
a very slow bisque fire. I always do hours and hours slowly firing,
and rarely if ever, lose anything. Anyway, the platters came out
beautiful and looked sparkling new. I was amazed, never expecting
such remarkable results. I wish you equally fine luck with your
piddle pot. ;- )
Catherine in Yuma AZ
>>
>>>I have just bought an old chamber pot made by Royal Doulton for not a
>>>lot of money. I'd love to use it as a planter, but the glaze has
>>>crazed, but not too badly I'm thinking that it's cast earthenware, with
>>>a plain white glaze and no decorations of any kind.. What would happen
>>>if I popped it on stilts and took it slowly up to temperature? Anyone
>>>any idea whereabouts that temperature might be?
>>>
>>>I've often come across interesting pots with crazed glaze, but never
>>>been tempted to try this before. Thanks for all your help.
>>>
>>
>>If you attempt this, I strongly recommend that you go VERY
>>slow at the start. If it is earthenware, the pot almost surely has
>>moisture trapped inside it, which will not come out simply by sitting
>>around at room temperature. If you raise the temperature
>>too fast, you'll have a lot worse than crazing!
>>
>>In fact, you might want to use your kitchen oven for this.
>>Start out with an hour or so on "low" (under 200F) and
>>work your way up to (say) 350F over a few hours. I used
>>this approach on a friend's earthenware mug that always
>>got hot in the microwave. I suspected trapped water, and
>>this approach indeed "cured" it... at least until the next
>>time he washed it!
>>
>>Which brings us to the fact that despite your best efforts
>>at reglazing, you pretty much have to assume that water
>>will somehow find a way into the body, which may very well
>>cause new crazing down the road.
>>
>>Nevertheless, this might be a fun project and if you take
>>it slow you don't have much to lose but the pot. As far as
>>re-firing temperature, I'd keep it under cone 04 if you don't
>>know anything about the body. If that doesn't heal the
>>crazing and you are still interested, maybe go to cone 1 or
>>2 max, watching through the peephole for signs of sagging.
>>
>>Please report back here if you try this!
>>
>I have a kiln with a firing ramp starting 25/40/60deg per hour. I
>should be able to crawl at low temperature for quite a while and then
>creep up the range. This should stop the thing heating up too quickly
>and, as you put it, gives me worse problems than just the original
>crazing. The kiln cuts in to full power at 600degC. My kiln's a top
>loader, so there's no way of checking through peephole for problems.
>Time to play safe at the lower temperature, if I go ahead and try this.
>
>I suppose on other way of going about this is to seal the inside of the
>pot with one of the polyeurathene varnishes. Probably a safer approach,
>but not as much fun. Any recommendations, please. From what you say
>Bob, I will probably have to do this after firing anyway.
>
>Of course, Bob, I'll let you know what happens if I do fire it.
>
>Regards
>Susie
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