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lifeofreilly57 · 17-09-2018, 21:10

Quote:

Originally Posted by er9

interesting. on my 1980 boat they used butyl between the hull and deck and between the keel and hull. im really curious what the bond between the keel and stub looks like when i eventually drop the keel. so far no signs of water intrusion in either yet. i wonder does butyl come in a semi liquid form?

Unfortunately no, it only comes in tape form as far as I know, although others contributing to this forum may know otherwise.
One of the boats I owned also had butyl rubber between the hull to deck joint, it was still flexible and totally sealed 30 years after the boat was built.
I've never heard of it being used for a keel joint, but then again I only know what I've seen in the boats I've owned and worked on.
From my experience in the chemical field, most substances like butyl rubber are formed and processed as a finished product, often times rubber products are finish formed by being run through giant calendars that form it under extreme pressure to a finished dimension while also imparting some of the characteristics of the finished product.
Most liquid or paste type sealants are actually catalyzed types, in some cases requiring being mixed with a catalyzing agent or in the case of silicone and other sealants of that type using the moisture or other components in the air to act as the catalyzing agent to start the chemical reaction to a semi-solid state. Which is why they usually suggest that you give the sealant some time in open air to start the reaction before putting the sealing surfaces together. I can still remember taking apart a small block chevy motor in the 70's that a friend had assembled, the silicone was still soft in the area he had bolted on the manifold too quickly without allowing the silicone to react, it was still liquid 6 months later with only the outer skin set up. It was a hell of an oil leak.