doorskin laminations

[bromleigh]

Just passing this along for the "Bretherin". Mahogany doorskin, "IF" it is laid-up and
encapsulated properly, (that is, glued with resorcinal and sealed with 2-part epoxy) is
the"CHEAPEST" and strongest, (trust me here I've done some submersion and strength
tests), form of cold-molding extant. Caveat,,, doorskin must be max thickness .120"
and mahogany. For applications over 30' dwl, max strakes are 6" by any length .
Three, forty five degree lay-ups with one exterior long, gives exceptional strength
and puncture resisitance, with a hull thickness of just .4678"

[Bob Smalser]

How do you tell if it's made of the good Luan or the bad Luan?

Don't recall seeing it in Honduras Mahogany.

[Bruce Hooke]

How did you achieve the clamping pressure required for resorcinol and why didn't you just use epoxy? It would seem to me that given the large areas involved when you are cold-molding a hull, and the high clamping pressure specified for resorcinol, that you would be talking about a LOT of pressure -- much more than could be supplied with the usual staples or vacuum bagging...

[Rick Crawford]

Luaun doorskin is not mahogany, but a variety of meranti. Meranti has approximately 25 different commercially viable species, but is not mahogany. Check the book on different wood species in the world for particulars on it. Sorry, don't have the exact title at hand, but a search will bring it up. At any rate, it varies as to hardness, color, and rot resistance. Meranti is most commonly found in pallet wood that looks like mahogany. I've used it in the past to make some very pretty keepsake boxes, and will use it in my 14' sharpie. My two cents worth...

Rick in Asheville, NC...just pacing the cage...

[John Blazy]

Sounds possibly like Bromleigh is referring to buying doorskin stock that was MADE with resorcinol, and THEN using epoxy to laminate in the cold-mould process. Doorskin stock sounds like a great idea for cold moulding. Is it three plies thick @ .120" ? Two plies would be better for bending and sucking up glue to the core.
Seems like a good idea, and cheaper than solid veneers.

[George Roberts]

I also think it is a wonderful idea.

6"x7' is a reasonable size to handle.

I don't know wht the properties are when laid up, but one could look in Gerr's book for cold molding scantlings and see what wood he recommends and what thickness he recommends.

From that one could determine if it is reasonble.

[Tom Lathrop]

Some time ago I built a couple of winding staircase stringers and laminated the interior plys with doorskins, covered with 1/8" ash laminations. It was done to save the work of resawing lots of wide ash veneers and it was also cheaper and easier. While the finished stringers were plenty strong, they were certainly less so than full ash laminates would have been.

I know of several dingys that were built with just a single layer of doorskin and they seem to be ok although no hobnail boots are allowed. For cold molding several layers on a boat, I see no problem although I would want a solid wood veneer for the top layer if the boat is not to be sheathed with a strong fabric and epoxy. The face veneers of doorskins are pretty thin and would tolerate no fairing or sanding.

I would insist on exterior doorskins as I don't believe that epoxy encapsulation is foolproof.