Chris Campbell Posted December 31, 2017 Report Share Posted December 31, 2017 I have been experimenting with laminating super thin slices of colored clay patterns onto both sides of a white sheet of clay. All went well until after bisque firing ... when I rinsed them in water small confetti shaped pieces popped off with enough force to travel a couple feet away. Woke me up! Glazed and fired them to Cone 7 and washed them again using a little more caution ... and a couple more zinged off. Needless to say, none of the work is for sale ... ... my prime suspect here is very tiny air pockets since the pieces were dry enough to fire for a couple weeks just waiting indoors for a kiln load. But ... there were no visible air pockets while in process. I might need to try slip between the color and the white to fill those little gaps. Any other ideas? Link to comment Share on other sites More sharing options...
Rae Reich Posted December 31, 2017 Report Share Posted December 31, 2017 Magic water? To keep the amount of clay to a minimum. It's a beautiful idea! Link to comment Share on other sites More sharing options...
Min Posted December 31, 2017 Report Share Posted December 31, 2017 Is there one colour it's mostly happening on? I don't think it's because of air bubbles/pockets. Think it's shivering. Link to comment Share on other sites More sharing options...
glazenerd Posted December 31, 2017 Report Share Posted December 31, 2017 Chris: earlier this year I was experimenting with 04 porcelain frit ware. I was trimming slots and in laying different color bands. The bands would crack, with some sections falling away. So I used some 04 clear glaze, watered down with an additional 50% water and lightly coated the areas where the bands were applied. The problem ceased after that; so I wrote it down as a bonding issue due to a lack of flux. You could simply add equal parts of sodium and potassium spars to water to accomplish the same goal. You do not want or need a lot, just enough to fuse the overlaid pieces. I do however find it curious that the problem did not show up until water was used to rinse. Sudden shock/ change in expansion? The yellow and blue bands are 1/8" in depth. Not exactly what you are doing, but along the same principle.. Removed pic.. Still cannot figure out how to down size them. Link to comment Share on other sites More sharing options...
Chris Campbell Posted December 31, 2017 Author Report Share Posted December 31, 2017 I got a reply on my ‘Color/Colour in Clay’ Facebook page from a person who is also experimenting with this. She was using vinegar in tap water and had the same issue. She switched to plain distilled water and it went away ... she thought maybe it was ‘lime pops’. Going to try it since I am using vinegar in tap water also. Link to comment Share on other sites More sharing options...
RuthB Posted December 31, 2017 Report Share Posted December 31, 2017 Hi Chris, I took a course with Curt Benzle this fall and learned a ton about working with thin colored clay. He leads a fantastic workshop. Problems with things falling apart are usually that the clay is either too wet or too dry when joining. Since you're having problems with delaminating, my guess is that it is too dry when applied, or not evenly wet and you've got wet and dry areas. How are you wetting the clay. Which side. How are you sealing them together. One idea that might help would be to place all the layers between two pieces of cotton sheeting and gently roll and flip them, and roll again. And you you might start a bit thicker than you want the finished product to be and roll it down to the final thickness. I'd love to know if this helps. Ruth Link to comment Share on other sites More sharing options...
Chris Campbell Posted December 31, 2017 Author Report Share Posted December 31, 2017 I keep all of the clay on a damp towel under plastic so they match each other all the time. This is why it was so unexpected ... my clays played very nicely together during building ... I thought my problems would come from other places. As usual, Clay is the teacher! Thanks !! Link to comment Share on other sites More sharing options...
Min Posted January 1, 2018 Report Share Posted January 1, 2018 3 hours ago, Chris Campbell said: I got a reply on my ‘Color/Colour in Clay’ Facebook page from a person who is also experimenting with this. She was using vinegar in tap water and had the same issue. She switched to plain distilled water and it went away ... she thought maybe it was ‘lime pops’. Going to try it since I am using vinegar in tap water also. Are you using plaster in the process somewhere? Unless you are contaminating the clay with plaster I can't see how it would be this. Jeff Zamek article on lime pops here if you haven't already read up on this. Link to comment Share on other sites More sharing options...
Chris Campbell Posted January 1, 2018 Author Report Share Posted January 1, 2018 No plaster anywhere in my work area. Maybe it’s not lime ... I have no clue. Never have seen a pop like this ... it shoots out from the surface with an audible pop and travels a couple feet from the force of it. Happened as soon as the pot got wet. Going to try losing the vinegar, use distilled water and see what happens next time. I do love mysteries. Link to comment Share on other sites More sharing options...
Sputty Posted January 1, 2018 Report Share Posted January 1, 2018 . Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted January 1, 2018 Report Share Posted January 1, 2018 I was thinking maybe some bits dried uneven and created tension in the lamination or some little bits were missing slip/ air bubble and made tension. Link to comment Share on other sites More sharing options...
glazenerd Posted January 1, 2018 Report Share Posted January 1, 2018 Sputty/ Joel: noted that above. Why did it occur when water hit the piece? A " safe" assumption would be the shard was already loose, and just that mild shot of temperature change finished it off. Stains change COE, but to what degree has yet to be tested. (To my knowledge) nerd Link to comment Share on other sites More sharing options...
Chris Campbell Posted January 1, 2018 Author Report Share Posted January 1, 2018 OK ... this new image might help better chemistry minds than mine. This is only happening under one pattern, the others are fine. From the image it looks like air bubbles but if my application process is off, why is it only off under one pattern?? I'm not saying I do it all correctly, but all the others are fine. Most of the action is happening under the pink which is Mason #6020 ... Manganese Alumina Pink Corundum, an inorganic pigment, is a reaction product of high temperature calcination in which Aluminum (III) Oxide and Manganese (III) Oxide in varying amounts are homogeneously and ionically interdiffused to form a crystalline matrix of corundum. Its composition may include P205 as a modifier. This needs brighter minds than mine chemistry wise. Link to comment Share on other sites More sharing options...
Sputty Posted January 1, 2018 Report Share Posted January 1, 2018 ' Link to comment Share on other sites More sharing options...
Chris Campbell Posted January 1, 2018 Author Report Share Posted January 1, 2018 Super easy to copy and paste! Link to comment Share on other sites More sharing options...
andros Posted January 1, 2018 Report Share Posted January 1, 2018 So weird... Looks like a kind of blistering... the behavior almost seems to suggest the presence of particles reactive to the water, like burnt lime (from calcium carbonate). This defect (even if not always is a defect) can occour in some clays for bricks, roof tiles and other outdoor objects. But hardly I can see this in a stain... Link to comment Share on other sites More sharing options...
Mark C. Posted January 2, 2018 Report Share Posted January 2, 2018 looks like lime pops whats in the water or slip for joining layers again? Link to comment Share on other sites More sharing options...
Sputty Posted January 2, 2018 Report Share Posted January 2, 2018 . Link to comment Share on other sites More sharing options...
oldlady Posted January 2, 2018 Report Share Posted January 2, 2018 gee, chris, people like blue, dump the pink and use cobalt. (please do not hit me.) Link to comment Share on other sites More sharing options...
andros Posted January 2, 2018 Report Share Posted January 2, 2018 5 hours ago, Sputty said: Someone who has a clue might find some explanation in there, but that person is not me... Here I can see no clue... Corundum is just aluminum oxide "doped" with other elements that give its color (in the case of the involved stain appears to be manganese)... sometimes corundum crystalline lattice can be tensioned and cracks because of big doping elements (i.e. chromium in ruby, and this is why it's so rare to have big rubies) but this is likely to happen only in big mono-crystals, and in this case, In my opinion, there is no explaination in the composition of the stain. Some foreign element\agent should be involved... Link to comment Share on other sites More sharing options...
Chris Campbell Posted January 2, 2018 Author Report Share Posted January 2, 2018 8 hours ago, Mark C. said: looks like lime pops whats in the water or slip for joining layers again? About 1 tbsp plain white Vinegar in 2 cups of water. Another potter said they had this problem and they used the vinegar water combo too. As I try to remember process ... this was all done before Holiday madness ... I think this was strung out over days so the water application might have been oftener with time for the solution to sink into the clay .... maybe I actually had layers of vinegar?? Link to comment Share on other sites More sharing options...
Sputty Posted January 2, 2018 Report Share Posted January 2, 2018 . Link to comment Share on other sites More sharing options...
glazenerd Posted January 2, 2018 Report Share Posted January 2, 2018 Taking a brief look, I see several things that could cause or contribute. 1. Corundum has an unique crystal structure as Andros pointed out. 2. It also has a very unique molecular mass at room temperatures; much different than " normal".which would translate to differing COE to surrounding materials. 3. Synthetic corundum ( which stains are synthetic) can also produce pockets of mica crystals with the right conditions of flux/heat. These might or perhaps not play a role. If I would venture a guess, I would go with door #2. Although it is a problem, one that doesn't.t fit the text books is always interesting to ponder. Link to comment Share on other sites More sharing options...
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