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Nancy S.

Member Since 05 Sep 2012
Offline Last Active Jul 21 2015 11:21 AM
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Topics I've Started

Mold On Leatherhard Clay

15 January 2015 - 10:10 PM

I've read all about what to do with mold in your slopbucket, but what about spots of mold on leatherhard pieces? I have some little ornaments that I put in a damp box, and they now have spots of mold after a year. I want to paint them with underglaze before bisquing but am not sure if the mold is going to affect the Amaco Velvet underglaze.

Should I scrape it off? Just paint on top? Use some diluted bleach to sponge them off? Thoughts, ideas, and suggestions are welcome!!

Glaze Flaking Off

29 November 2014 - 08:26 PM

I looked around and didn't find any other posts on this, so hopefully it's not a stupid question.

I have a bowl that I glazed today with two others. They were all bisqued to 05, all made of Standard 630. I sponged them all off and glazed them in Coyote black, then one got a few layers of Plum Shino, while the other two got Leopard Shino. One of the latter two...well, it looks like the Shino flaked but the black is still on. What caused this? Too much water when cleaning them off? Or something else? Also, what's my best option to fix this one? Scrape off the flaky bits and reapply? Or do I have to wash it all off and start over?

Standard 630 - Glazes Crazing

06 November 2014 - 09:32 PM

I've been throwing with Standard Clay 630 (^6 white stoneware) this year and have really been enjoying using it. However, I used a few different commercial glazes with it and have found that some of them are crazing. For example:

 

Amaco HF-9 Zinc Free Clear

Amaco PC-40 Celadon

Amaco Sahara Yellow

Coyote Light Blue Gloss

 

All of these are translucent, so maybe that's the common thread? Because Amaco's Ultramarine, Amaco's Amethyst, and Coyote's Buttercup didn't craze at all. But I tried my local studio's zinc-free clear, and it didn't craze.

 

It's not the cooling, because nothing is being fired any differently than other pieces that don't craze. So I'm thinking it's a COE / glaze fit issue...but I am a total newbie at glaze chemistry, so I bow down to the collective knowledge of the forums and ask if there's anything I can do to my commercial glazes to make them fit.

 

Other than changing clays, of course. Which is probably what I'll have to do, but I like the 630 the best out of the ones I've tried and I really love the celadon and light blue glazes...

 

Also, how serious is this breed of crazing? Is it really *that bad* when it comes to using them for food/drink??

 

 

(Regarding clays.....I know some of you swear by clays made by Highwater, Laguna, etc., but I live in Pennsyltucky and getting anything other than Standard isn't an option right now. Also, I am a hobby potter and porcelain is out of my current league.)