What's this silver stuff (rubber like) under my canvas?

[CharlieCobra]

I have a small patch of canvas to repair. The bottom of the piece that came up had a silver rubber looking paint under it. What is this and where can I get it? The rest of the deck looks Fab, even after 46 years.

[jimmy]

I suspect the reason you aren't getting any replies is that it doesn't sound like your deck has been canvassed using any of the standard/traditional methods and it's hard to guess what the silver rubbery substance might be. If the deck is 46 years old the product is probably not available anyway. It think all you want to do is find a product that is chemically compatible with what is there and has similar properties. I know that is difficult if you don't know what it is. Try posting a photo, people love photos. Some thing I know about that are often under canvas decks are white lead paste, felt, and paint, none of which match what you describe. It might just be some rubbery deck paint.
James

[CharlieCobra]

Yeah, it almost looks like the rubberized coating used on mobile home roofs back in the 60's and 70's. Apparently it worked pretty well. I don't think the deck's ever been redone on this boat.

[Plover]

I know just from history and a lot of reading that those old timers that built boats used just about anything they could get there hands on, that worked and was cheap. At first guess would be that some along the way did the canvas and if not it should have a heck of a lot of paint on it. If it is silver roof coat you should be able to still smell the asphalt in it you scrape it. Pete Culler, the guy that built my boat was notorious for using tar and asphalt. I do have white lead paste under my canvas (which all does have to be replaced) and he used roof patch (asphalt tar) as seam compound below the water line. When you pull up the nailed edge look to see if it has extra nail holes and what kind of nails were used that should help you age the stuff to see. Find a small area near the edge and scrape down to the wood and see if there is a layer of white. The white lead paste doesn't really dry under the canvas. Yes, in time it sure does. If it is roof coat and none bled down into the cabin, I'd use the same stuff. Best of luck on that one.
Paul

[Seagull]

That rubbery stuff may be one of Callahan's(spelling?), miracle products, Serapne or a name similar to it that was a rubbery liquid intended to waterproof hulls, decks, cabin tops, you name it. I'm talking 50s 60s time period. It worked pretty good on flat tops but mostly failed in hull application. It would separate from wood hulls eventually. As for bedding canvas, we often used material that settled to the bottom of a large drum of kero we used to first clean paint brushes. That thick goo at the bottom of the drum among other ingredients contained lots of white lead. Worked great under canvas, protected the underlying wood without hard gluing the fabric to the wood allowing for the canvas to drum tight after edges fastened and lightly sprinkled with water. l

[Bob Adams]

I suspect it was "Aluminized Roof Cement". Just because it doesn't say marine, doesn't mean it's not good. Just not as expensive.

[CharlieCobra]

Thanks Guys.