Mug Posted October 27, 2014 Report Share Posted October 27, 2014 Razor stand/brush holder and a razor brush mug stand sagging. The stands are made in two separate pieces of Standard white stoneware cone 6 casting slip. The top and bottoms are simple one piece molds. The handle for the cup is two pieces, and the cup is a one piece. I have to remake the mold base to keep the razor from slipping out of the stand, this was an unseen in the prototype... Note to self: Hard glaze is slippery. Overall I like the design and would like to stick with it. The top needs to be flat to keep the intended aerodynamic look. I new these would sag a bit when I test fired 6 of them. In the pictures the blue one with the cup was left to sag unaltered, the other two were bent up slightly over a thickness of wood after they were cast to compensate for the sag. The sagging was more unpredictable than expected. The blue brush razor stand is an example. I would assume that some unevenness of the bend and possibly unevenness in the kiln temperature might be the problem. My kiln seems to heat pretty even according to the cone packs. I was thinking about firing them unassembled on a kiln shelf, then gluing them together to keep the tops flat. This would suck up space in the kiln. Any suggestions to keep this flat would be appreciated. Thank you ...Fred... Link to comment Share on other sites More sharing options...
Chris Campbell Posted October 27, 2014 Report Share Posted October 27, 2014 I like the way it looks. Sorry, not helpful for anti sagging tips. Link to comment Share on other sites More sharing options...
bciskepottery Posted October 27, 2014 Report Share Posted October 27, 2014 Maybe make the top piece from a slab -- but make the clay toothier by adding some grit/kyanite for strength. Maybe add a wedge/triangle underneath the brush side to give the top a bit more support -- large enough to support but small enough to not interfere with the cup or brush. Link to comment Share on other sites More sharing options...
High Bridge Pottery Posted October 28, 2014 Report Share Posted October 28, 2014 Love the iron over seaweed glaze. Making me drool Could a little half arch going from the vertical piece to the horizontal combat some? Maybe. I think the bending in the opposite direction seems to have worked. Link to comment Share on other sites More sharing options...
Chilly Posted October 28, 2014 Report Share Posted October 28, 2014 Like Chris, I love the sagging. However, if you don't want that, maybe try a different slip. One that vitrifies at a higher cone might not sag at ^6, or fire to a lower cone. Do they need to be ^6? Link to comment Share on other sites More sharing options...
Mug Posted October 28, 2014 Author Report Share Posted October 28, 2014 The wedges underneath would stiffen it up, I could not think of a simple way to incorporate them into the mold. I was wanting to keep the drip trays under the brush and razor. If I were to add wedges it would have to be in a way that would release from a mold. I have been thinking about wedges for days, and as I am writing, I may have just figured out a way with a two part top mold. Brainstorming works better when there is more than one brain. grit/kyanite, may help I'll have to look that up. The seaweed glaze and some others were in on this test run. The seaweed is a dry mix from Standard. The Iron is messy and easy to transfer to unwanted places with your fingers. I brushed on the glaze for this sample in various ways to see how it would look. Learning from this test the next run will be dipped and sponged and should be better. Overall I like the colors and think the glaze is a keeper. I hope others will like it as well. I had some misting on the kiln shelves from a couple of the glazes...not real crazy about that. The slip would not have to be a cone 6. I would like it if the stands could survive the dishwasher multiple times. ...the glazes are 5/6, but they would need a longer soak time at cone 5. This batch was fired pretty quick with a cone 6 bar in the kiln sitter, the glaze would probably look better with a 7, but I was aiming to reduce the sag. Link to comment Share on other sites More sharing options...
neilestrick Posted October 28, 2014 Report Share Posted October 28, 2014 You're experiencing pyroplasticity. The clay is approaching its melting point and is starting to soften. Any large overhang like that is going to sag. Either figure out a way to support it, or fire lower. Link to comment Share on other sites More sharing options...
Mug Posted October 28, 2014 Author Report Share Posted October 28, 2014 Yep... looks like some new molds today. Thank you Link to comment Share on other sites More sharing options...
Stephen Posted October 28, 2014 Report Share Posted October 28, 2014 great piece and as others have said I like the slight sagging, gives it a kind of tired look that matches the mug that is fixing to shave. Hey have you thought about just doing the tops like tiles. Sandwich them between drywall for 24-30 hours with weight on them and then air dry flipping every so often. Like you said you could then just glue the final piece together. Link to comment Share on other sites More sharing options...
Mug Posted October 29, 2014 Author Report Share Posted October 29, 2014 Thank you, I would have never though the sag would be attractive. I solved the problem by designing a 2 part top mold that includes the wedges. The top will assemble 3/4 of the way up right below the wedges. I just hope the seam line will clean up easy and look seamless when assembled. I avoided this in the original because the top piece is 3/8" thick. Filling the mold is simple. Getting the slip to drain out well, is the part where I'm troubled. I will vent it, and hopefully the vents will remain open. My other thought was to cast the top in a pre-bent curve, but that would still mean a two part mold. The original was an open pour mold. The top part was U shaped viewed from the underside. I thought this shape along with the ridges in the top would make it stiff enough to keep it from sagging. I could make the top from solid clay, but that may make the stand top heavy. Link to comment Share on other sites More sharing options...
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