How similar to RTV silicon is Selley's gap-seal silicon?

Just curious, after watching a demo at the local hardware of rtv silicon mold making, the end result looked very similar to what I get when using gap sealing silicon.

Reply to
Wayne
Loading thread data ...

If it's a solvent-based (one-part) silicone, it will shrink as it hardens, whereas two-part, catalyst type RTV does not. Most tube silicones are also adhesives, so a master part will have to be generously coated in mold release or it will be permanently bonded in the silicone when it hardens.

Gerald Owens

Reply to
Gerald Owens

I know about the shrinkage part - had to redo around the shower because of it.

That satisfies my curiosity.

Reply to
Wayne

While others have pointed out the shrinkage and adhesion problems, I do remember seeing, several years ago, an article in FSM about duplicating very small parts using the tube stuff to make the molds.

Reply to
Don Stauffer in Minnesota

Does silicone have solvents? I thought it was a hydrolysis thing, where the rubber is somehow held in solution by being an acetate, but exposure to water in the air makes the acetate come off (thus the vinegar stink) and the exposed sites on the rubber polymerizes. I'm pretty fuzzy on the details, obviously.

Reply to
z

You are essentially correct. The one part hardware store silicone sealant isn't actually disolved in acetic acid. It cures by absorbing moisture out of the air which allows it to polymerize. Acetic acid vapor is (smelly) a BYPRODUCT of the reaction.

Greg

Reply to
Greg

Since we're a bit off topic anyway....as an aside, DO NOT use run-of-the-mill tube silicone around showers, windows, doors, etc where there is contact with mortar. The acetic acid reacts with the lime in the mortar and deteriorates it, making it crumble fairly quickly. Use only non-acid silicone for these applications. Even the paintable caulk "with silicone" is acid based,so beware.

Reply to
Disco58

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.