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Min

Member Since 31 Mar 2010
Offline Last Active Yesterday, 03:28 PM
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Topics I've Started

Crazing, Yes, No Or Maybe?

05 July 2017 - 10:18 PM

There was a bit of a discussion on another thread about crazed glazes on functional pots and whether or not this is an issue if the clay is vitrified. For the most part I make functional everyday pots, vitrified clay, and my glazes don’t craze. I was taught that functional pots shouldn’t craze, significantly weakens them and craze lines can stain.  If the clay isn’t vitrified then crazing causing other issues like moisture getting into the pot, get really hot in the microwave and possible bacterial growth in craze lines. Also, not sure how pleased customers would be if my glazes crazed after use. I’m guessing that for the most part if they didn’t buy a crazed glaze to start with they are not going to want it to craze later on. I could be wrong, I don’t know but I’ve been doing it like this for years and perhaps should rethink this. I think crazing on a coloured transparent / translucent glaze is beautiful.

 

So, if you make functional pots with vitrified clay, for your own use or for sale, what do you think? Crazing inside, outside, neither, does it matter? 


Epoxy Thickener?

09 April 2017 - 12:58 PM

I need to thicken some 15 minute epoxy for joining small pieces of porcelain (unglazed) with driftwood (some pieces are super porous) I’ve never done this before and reading up on it there seems to be a lot of choices for thickeners. It needs to dry clear, is there something that works best? 

 

Thanks in advance for any suggestions.


Glazing

25 February 2017 - 02:06 PM

Came across a glazing demo, covers the basics with quite a few tips. Seems like there are a lot of posts here about basics of throwing but not glazing. This one is kind of a glazing 101 for dipping and pouring. It's long but might be helpful for anyone just starting out. If anyone else has come across any good demo's of glazing it would be nice to see those too.

https://www.youtube....h?v=r3RSJcOfhw8


Element Support Tubes

12 February 2017 - 04:52 PM

Anybody know anything about the pros and cons of supporting kiln elements like they do in some kilns from european and asian countries? My first thought is the likelihood of banging into them with a shelf, higher manufacturing costs and more labour intensive to change elements? Seems the heat loss into the softbricks would be less therefore resulting in lower operating costs. I'm thinking there has to be a reason they are being made like this. The Nabertherm one in the picture below is rated to 1340C.N1500_fmt.jpg

 


Clay Vs Glaze Coe Figures?

03 January 2017 - 01:44 PM

I’ve been running glaze tests on Laguna’s WC-429, I contacted Laguna and was told by Jonathan Pacini that the COE figure (using their methods of testing) is 4.60 x 10 -6. My question is what is a reasonable expectation of a COE maximum figure for a clear glaze to fit this? My current low COE glazes are in the 5.7 area. When I shock tested them they appeared to survive on this clay without crazing but I'm not 100% sure since it's so hard to see crazing on a dark body.

 

Wondering if anybody has run tests comparing clay COE figures with glaze COE and come up with any data on a range where the glaze still fits.  I know that glaze calc COE’s only get you so far and some glazes with a higher COE might fit whereas lower ones don’t always do due to the family of fluxes used but just asking in general terms here. Even glaze coe versus published clay coe figures would be helpful for me to determine a working range of figures.

 

(I asked Laguna for sample glaze recipes that would fit and their commercial MS 29 was suggested, I’m not using commercial glaze though so that was no help) 

 

Any thoughts or insight? Thanks in advance for any help.

 

edit: I know I should run a series of tests from lower to higher coe's but am trying to find out if anyone knows of a window range? Trying to come up with a coe under 5 would be fun.