Stellaria Posted April 6, 2014 Report Share Posted April 6, 2014 If you wanted to make bread loaf and oblong (like a 9"x13") pans, and could not locate plaster hump or slump molds for either, how would you go about it? I have access to a slab roller, metal baking pans, and glass baking pans. I have done no handbuilding since returning to pottery this year after 22 years away, and never worked with hump or slump molds then. I know I can look up techniques, and experiment, which I will do....but I'd like to hear how experienced handbuilders would go about it. How would corners and edges be addressed, what release agents would you use, when would you remove it from the mold, would you hump or slump, etc. Link to comment Share on other sites More sharing options...
Pres Posted April 6, 2014 Report Share Posted April 6, 2014 I would probably build a form out of cardboard if it were a short run of 10 or so. Otherwise I would make a square plaster block, and carve it before it were completely set up. Fine sand and finish with a plaster screen when stiffer. Link to comment Share on other sites More sharing options...
Min Posted April 6, 2014 Report Share Posted April 6, 2014 It's not handbuilt from a slump/hump mold but from thrown and rolled pieces if that would work for you? I throw the wall with a small flange on the inside bottom edge and a rolled rim to help grip the pot when taken from the oven.These are quick to make up and not much trimming. Throw a baseless wall with a flange on the inside of about 1/2". Form the rectangular shape of the wall while still quite soft. Throw or roll out a base and let it stiffen up slightly. Foam batt on top of the wall piece, and flip upside down, I do this as soon as the wall is dry enough to support itself. Put the slab on and mark where the join will be. Flip back over so bottom of wall is again on top, remove slab, score and slip the wall and base. Flip right side up again and secure and smooth flange on inside edge, trim outside edge and compress with a pony roller or rib along the outer edge plus where the wall and base meet. Use low expansion clay and glaze and avoid sharp corners, round the inside edge as much as possible. The one in the picture is years old, it has stood up well with no cracking. Link to comment Share on other sites More sharing options...
Chilly Posted April 6, 2014 Report Share Posted April 6, 2014 Cover outside of existing tin with cling film fill inside of tin with scrunched up cloth/paper to hold clingfilm in place, roll out clay, press around outside, "welding" corners/sides. Allow to firm up, remove tin, smooth inside and out. WD40 also makes a good "release" agent for non-absorbent moulds. Works well for "one-offs", for multiples, make cardboard mould and pour plaster to make hump mold. Link to comment Share on other sites More sharing options...
Bob Coyle Posted April 6, 2014 Report Share Posted April 6, 2014 I would get a chunk of 2" x 12" from a lumber yard (sometimes they have trim ends that they are throwing away. Cut it 9" x 13" and cut a bevel on all sides. /___\ This forms an inside mold that works great. I use them for my senior center beginning clay class. They release almost as well as plaster if you dust them with corn starch. Link to comment Share on other sites More sharing options...
Pres Posted April 6, 2014 Report Share Posted April 6, 2014 Bakers spray works well as a release agent also. Link to comment Share on other sites More sharing options...
Karen B Posted April 7, 2014 Report Share Posted April 7, 2014 If you have a specific size in mind, account for the clay shrinkage before making the mold or, as you probably remember, you will be quite surprised when you take your tiny pan out of the kiln. Link to comment Share on other sites More sharing options...
DarrellVanDrooly Posted April 9, 2014 Report Share Posted April 9, 2014 I've only made a few baking pans (must make more!) when i did, I just got a real baking pan at the thrift store, coated the inside with petroleum jelly, and then plastic wrap, then just pushed a thick slab into the pan, let it dry then cleaned it off and added handles. Darrel Link to comment Share on other sites More sharing options...
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