Black Sealer

[Jastafford]

In disassembling multiple places on my 1972 42 classic I am finding the use of some type of black sealer. Some places have brown which I understand is Dolfinite. The Dolfinite is still soft in some places but hard in others. I picked up Dolfinite and have used it in a few places like bedding the quarter round trim between the deck and cabin sides. Also used it to bed a new front fixed window. The black stuff is soft, stretchy and sticky everywhere I have run across it. It almost seems like the same stuff that is between the teak strips that make the deck. I just pulled the rear companion way frame and some of the middeck. The used it on top of the "rafters" before the laid down the plywood for the mideck. In pulling cabin sides it is again between the plywood and framing.
Anybody know what material this is? It has performed so well I would like to use it in my repairs if it is still available.

[Richard Werner]

May be something like this - https://www.bestmaterials.com/butyl-rubber-sealant-caulk-1103.html

[gsanchez]

Maybe Life Calk or similar?

[Jastafford]

the stuff used could never be sanded as its still soft after 47 years

[gsanchez]

¿soft and deformable or soft and elastic?

Life Calk is a polysulfide sealant that is not very adhesive but will remain elastic.

[Sangraal]

I would look at using Bed-it butyl tape for windows. It will not set and will allow differential movement between the hull and the frame. A thin bead of caulk can be applied along the edge for cosmetic / secondary seal. The same goes for all fittings. The stuff works.