Food grade silicone to seal a lid

[TaliehCarmel]

Has anyone used food grade silicone to make a ceramic lid air/water tight? I am wanting to make a set of apothecary jars of varying sizes and shapes with somewhat elaborate lids, and wondering if I can add a layer of silicone between the lid and the gallery or between the lip and the flange in order to make it seal? I don't know of anyone doing this, and I'm not sure if it's just because no one has really tried it or if it's just not a good idea. My thought is to have the silicone attached to a section of bare clay body and then using a high gloss/smooth glaze for the other part.

If something like food grade silicone is a bad idea (I'm particularly worried about longevity of use), is there another method others have used in order to create an air/water tight seal on a ceramic lid?

Thanks!

[Bill Kielb]

These are very hermetic and glazed virtually everywhere. Fully vitrified porcelain, very low absorption. Food grade gasket is silicone as I recall. Also have made bottle tops with food grade O rings that just push down into the bottle opening that work for non pressurized bottles. There are forms for threaded tops as well wherein which a flat food grade gasket could mate with the top and the gasket could be glued inside the top. Most of what we have done has been to work out the shrinkage then fit the form to some simple sealing method. A bit tedious to start but once worked out pretty easy to repeat.

Food grade gaskets, O rings, corks come in many sizes and provide a bit of  wiggle room for variation.

For the jars what I picture is a round opening that the top fits in. Double O ring seems simple to seal the top effectively.

Just some ideas that may give you ideas

[Callie Beller Diesel]

If you go onto laboratory supply websites, you can purchase black rubber stoppers in the same sizes as a lot of corks. If you can make your design work with a stopper, it’s one way of creating a seal. There’s lots of outfits in Calgary that keep water labs supplied, and I can walk in and while case price is definitely cheaper, they’ll  sell me individuals if that’s all I need.

Good places to get graduated cylinders, mesh for diy sieves, and scales too. You can get soil sieves there, but they tend to have cross supports in them that make them difficult to clean glaze out of.

[GEP]

I use silicone gaskets too. These are not completely airtight, because the lid is not being held closed with pressure (Bill's jar with the wire harness will be more airtight). But this jar keeps my coffee beans fresh until I reach the bottom of the jar. The hard part is to make the lid the right size and shape to fit the gasket, accounting for shrinkage. And to make the jar body fit the lid. 

The silicone gaskets are easily found on Amazon. I have several jars (not hand made ceramic) with similar gaskets, and the gasket does wear out after a few years. But they are easy to replace.