By request I am posting what I know about using silicone to fix pottery. Note, I am not a safety specialist. If need be, consult one.<\/p>\n
The gold schtick of traditional Japanese Kintsugi interests me but does not serve my desires. Its not that a tube of urishi resin is so expensive. On a 50$ pot while it might not be practical it does raise the pot, it becomes more, the story of it longer, more involved. Its the gold thing. It does not suit me. I am a fan of what I call “Just Repair”. Gold is conspicuous and does not fit.<\/p>\n
Then there is the urishol thing. Urishi resin has the same name as urishol for a reason and I have no business playing with poison ivy rash incarnate. I have trouble keeping toothpaste off my nose. I should not use something that requires that much care.<\/p>\n
I read about people using epoxy to repair pots. Its not a great material for this. It does not stand heat. Unless it settles deep into texture it does not adhere that well. Its not wonderful in dishwashers.\u00a0 One day I happened upon food grade silicone.<\/p>\n
They make caulks for making gaskets. I used some on my Datsun 510. It holds up in the cooling system. Under pressure this can be in excess of 100\u02daC (212\u02daF, or 142\u02daT). Its also used with oil gaskets that might be hotter.\u00a0 We bake on silicone. Its a great surface.<\/p>\n
So, I took some of this silicone and used it to repair a mug. The first repair was on a knockoff Victor Insulator mug. It is thick and very vitreous. I bought the silcone on\u00a0 Amazon, it was Food Grade NSF FDA RTV Silicone Sealant Adhesive Red High Temp 10.3oz by Silco Incorporated<\/span> . It says it is good to 500\u02daF<\/p>\n The second silicone I bought was black. Silicone RTV 4500 FDA Grade High Strength Silicone Sealant, Black also Silco.\u00a0<\/span><\/p>\n I finished breaking this cup apart into three pieces. There was a visible crack in the bottom but it had not spread yet. I should have busted that one open too, but I was too timid. I left it. I spread the red silicone onto each surface and pressed it together. I held it while it set with cellophane style tape.<\/p>\n I used this cup hard for two years. I subjected it to over a hundred runs through the dishwasher and probably 50+ times in the microwave. The repaired cracks are still intact. The small crack that I did not repair started to seep. Its important to understand that silicone caulk is not rigid. I took a chisel and a hammer and encouraged the crack to finish going to an already repaired seam. I opened the crack with a thin blade and then squeeged silicone into the crack until it came out the other side. The old seams did not let go. I am using the cup again.<\/p>\n Technique. Cut the top of the silicone with a thin hole. Squeeze it right out onto the clay surface to be joined. In general you want enough to squish out both sides but not much more. Assemble the first to peices. If need be tape them together. Then add more pieces. Wipe off the excess before it dries. You can use just a clean rag, but it is often easier if its dampened with acetone. I do not care what they say about acetone. Use good ventilation and\/or an organic vapor mask. Its hard to clean it up after it dries, do a good job.<\/p>\n For\u00a0 medium chips put some silicon where you need it trying to not have surplus nor a shortage, just right. Dip your finger in dishwashing detergent. Spread it around a finger tip until it is well coated and still wet. You do not want your finger drippy. You do not want it dry. Use your finger in few careful pats to get the silicone where you want it.<\/p>\n Bigger chips. Get some Tin Copper, or Tin Copper Silver solder meant for potable water pipes. Do not use lead\/tin solder. Melt a piece on a piece of wood, or kiln shelf bigger than you need it. Hammer it until it is the right thickness. Cut it with diagonal side cutters or something else until it fits the spot well. Use a file if need be. Its soft. Use a smooth metal working hammer if you want a smooth surface. Glue it in place with silicone.<\/p>\n Food Grade. I live in the US. Things that come in contact with food have to meet FDA standards. Before being taken over by radicals, things had to be shown to be safe. Now? Who knows?Last I looked there were two different certifications for silicon. One was for incindental contact, like to seal a cabinet for food. The other was for planned contact with food like in a mixing machine. You want this second certification or its equivalent. FDA CFR 177.2600<\/p>\n","protected":false},"excerpt":{"rendered":" By request I am posting what I know about using silicone to fix pottery. Note, I am not a safety specialist. If need be, consult one. The gold schtick of traditional Japanese Kintsugi interests me but does not serve my desires. Its not that a tube of urishi resin is so expensive. On a 50$ […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1429","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=\/wp\/v2\/posts\/1429","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1429"}],"version-history":[{"count":10,"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=\/wp\/v2\/posts\/1429\/revisions"}],"predecessor-version":[{"id":1440,"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=\/wp\/v2\/posts\/1429\/revisions\/1440"}],"wp:attachment":[{"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1429"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1429"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/louiskatz.net\/wpt\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1429"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nThis is not something for someone without an inherent ability to work neatly to try.Unless you don’t care about the repair’s neatness.
\nGet your act together. Assemble disposable rags. I use old blue jean pieces and old tshirt pieces. Acetone is nice for cleanup. Get some tape and\u00a0 disposable work surface like an old box. Get some liquid hand washing dish detergent or liquid soap.\u00a0 Put a small amount into a reused container. I use about a tablespoon in an old prescription pill bottle. You want all this stuff easy to get to.
\nPractice putting the pot together Use tape to hold it together. Make sure the joining surfaces are clean.<\/p>\n