ronfire Posted October 19, 2016 Report Share Posted October 19, 2016 I have read that pots with lids usually get fire both bisque and glaze with the lids on. I have always fired them separate but on the same shelf if possible so they get the same heat works. My worry has been breakage with rim lock issues of breaking the pot or lid . Has this been an issue for some or just my worry of a problem. I have fired flat plates stacked and find they break and thought it was due to rim lock so that is why I worry with lidded pots to fire them assembled. I also let them dry separately before firing for the same reason and figure I can always trim the dry lid to fit better if required. With firing the lid separate I have had a couple that did not fit well when finished. Link to comment Share on other sites More sharing options...
Joy pots Posted October 19, 2016 Report Share Posted October 19, 2016 Hi, I have found it best after trimming to dry pot lids on their pots to prevent warping on both rims, likewise they should be fired together always to keep them true. You need to wax both rim & pot connection & wash away any glaze residue in the glaze fire. A light tap with a wooden dowel easily separates hard to lift lids. Joy Link to comment Share on other sites More sharing options...
neilestrick Posted October 19, 2016 Report Share Posted October 19, 2016 Lids fired in place can fuse even if they don't have glaze in the joint. It's best to put a little alumina hydrate in your wax. The alumina is very refractory and will keep the lid from fusing to the pot. Lids can also get locked in place if the pot is not built correctly. For lids with flanges that go into the pot, the flange must angle inward. For lids where the lip of the pot has a lid seating, the lip of the pot must be thick enough that it doesn't move. A very thin lip can move inward due to the weight of the lid and end up locking the lid in place. Link to comment Share on other sites More sharing options...
Min Posted October 19, 2016 Report Share Posted October 19, 2016 Quick fix for sticky / too tight lids after glaze firing. Mix some silicone carbide (I use 100 mesh) with a little bit of toothpaste and smear it around the flange / rim and then twist the 2 pieces back and forth. The silicone carbide is abrasive enough to grind the 2 pieces down to fit. (It also makes the edges super smooth) If you can find water based valve grinding compound that works too. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted October 19, 2016 Report Share Posted October 19, 2016 Min, That is a new one on me. Good idea. I'm with Neil as far as adding the alumina to liquid wax on lids...I use it on feet as well for porcelain. Keeps the foot from grading the shelf and the lid from fluxing together. Marcia Link to comment Share on other sites More sharing options...
What? Posted October 19, 2016 Report Share Posted October 19, 2016 As long as there is no glaze or design issue you should be fine. If the lid sticks use the corner of a razor blade and tap it with a hammer. Safety first of course. Link to comment Share on other sites More sharing options...
Mark C. Posted October 20, 2016 Report Share Posted October 20, 2016 I always fire lids together when I can. I have bisque a few separate to save space-They usually are turned upside down to be shorter in bisque fires and well as something loaded on top of them. Lids are something one learns about and try to master. The alumina in the wax is what I do so they do not stick (porcelain). I measure all lids in metric and write that on underneath in the clay-the glaze covers this later.All my lids of some forms are all alike so making anew one is easy. Butterdishes are 17mm all honey pots 10mm. If you do this you will have less issues as they are all alike. Easy to replace., Link to comment Share on other sites More sharing options...
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