lakabarra Posted July 21, 2019 Report Share Posted July 21, 2019 Hi, I'm new to the forum and new to ceramics as well! I just made three hanging baskets over metal kitchen bowls. I thought some cooking oil is all I need to release the forms, but I start doubting it. When is the right time to release? Letting it dry over night? (I know it was a silly idea to not put anything between the bowl and the clay). The bowls are not flat either- is there any chance to release them in one piece? Link to comment Share on other sites More sharing options...
Bill Kielb Posted July 21, 2019 Report Share Posted July 21, 2019 Hopefully the profile allows them to release as they shrink. Sump molds, no problem, slump molds can catch, shrink and crack as they shrink. Most of the hand builders I watch use cornstarch or simply put a nice smooth fabric sheet over first and separate as soon as their clay will retain its shape. Your pictures indicate you have a hole in the bottom of your clay which would prompt me to gingerly (really slowly) blow air in the hole as this stiffened a bit in an attempt to gingerly get these to separate. I am sure there will be many and probably better ideas by hand builders here as well. Link to comment Share on other sites More sharing options...
liambesaw Posted July 21, 2019 Report Share Posted July 21, 2019 In school we either used newspaper or plastic bags between the mold and the clay, anything works though... Link to comment Share on other sites More sharing options...
lakabarra Posted July 21, 2019 Author Report Share Posted July 21, 2019 Thanks for that, even if they crack I learned something! I will blow into the hole (it was meant to be a drainage hole...) Link to comment Share on other sites More sharing options...
lakabarra Posted July 21, 2019 Author Report Share Posted July 21, 2019 btw it was big fun to do these Link to comment Share on other sites More sharing options...
JohnnyK Posted July 21, 2019 Report Share Posted July 21, 2019 5 hours ago, liambesaw said: In school we either used newspaper or plastic bags between the mold and the clay, anything works though... I think the plastic would work better here since the texture on the inside of the planter would not be critical...Murphy's oil soap might work too... Link to comment Share on other sites More sharing options...
PSC Posted July 21, 2019 Report Share Posted July 21, 2019 I have used veggie oil as a release but i once used old veggie oil and it actually seemed to adhere it to the shape worse so make sure the oil isn't real old. Also dry cleaning bags, cling film or silk make for a good barrier to sticking. Link to comment Share on other sites More sharing options...
lakabarra Posted July 21, 2019 Author Report Share Posted July 21, 2019 This morning I did put them out, one was cracked (thankfully clay can be recycled). The first one I made was good, but the second one I probably smash too because I think the wall is too thin (a bit under half a centimeter. I guess next time I'll try to use thin fabric or newspaper or plastic. And I will make the walls thicker, maybe using two pieces of wood on either side. Is there a rule of the thumb between diameter and thickness? Link to comment Share on other sites More sharing options...
lakabarra Posted July 22, 2019 Author Report Share Posted July 22, 2019 I did one with plastic, the release was possible but difficult. It sticks like mad. I guess the reason why all these youtube videos on soft slabs are with shallow molds is because shallow molds are more suitable for that. It has to be taken out early because of the shrinkage and then the whole bowl is still very pliable. Link to comment Share on other sites More sharing options...
Magnolia Mud Research Posted July 22, 2019 Report Share Posted July 22, 2019 I have found that the best results (for me at least) come from using three layers (one to stick to the mold, one to stick to the clay and the middle layer to NOT stick to both) of paper (newsprint or paper towels) between the mold and the clay. Link to comment Share on other sites More sharing options...
Min Posted July 22, 2019 Report Share Posted July 22, 2019 Another approach would be to use the metal bowls as slump rather than hump molds. Use a spray vegetable oil on the inside, remove the clay when it's leatherhard then attach the texture pieces to the outside. Don't have to worry about the clay shrinking on the mold and cracking if you slump the clay inside the bowl. Link to comment Share on other sites More sharing options...
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