Re: Glue, caulk, Strip Planking on small craft, Some Observations

Electri-Cal
 

I have had the "black hand of a Gorilla " too often, gloves or not it's no fun.  The foaming sucks to sand off, mask required !!!   The trick is to have it hold quickly, but have time to tape stripped ( I like the one and a half by say 5/16 inch, makes about 3/16 inch hull ) parts together, from a 2 by 8 straight grain cedar with correct grain for stripping.  We all know how to select boards with correct bending grain so it lays smooth and beads well, that's basic shop talk.

Needs those smooth curves with less lofting effort. Knots and flaws in grain make smooth curves more difficult, and / or break at the chine, or bow rise when bending.   Non perfect grain is way less strength as hard spots, that can pop free when forcing the curves.  I learned that some  $$ wood quality savings make things way tougher to get a smooth sanded flow of hull shape.  Almost have to build one, or a sample  curved panel first, to get the idea.  You can get the strips out in a mornings cutting to do an 8 ft.. dink, only one removable center mould, mine is still in the barn.  Bow and stern pieces are the real ones in most small boats, or a close start.

You tube has ideas and tests, good ones.  I just looked in my shop and the top result is my current stock of 3 tubes (for accurate "beads" ) of  reliable Loktite PL Premium, the 3X stronger type.  It goes on well, wipes ( 2 in. metal spatula ) out of seams to flush off, sands after curing and flexes about like the base strips to hold.  Turns out that's a top  Brand pick from the web site.  I did tests, built boats, decks, bulkheads, and never had a worry on the water.  Rubber gloves and H Freight shop LED light bars are a good idea, and a fan of course.

Did that get it answered??  I have sample panels or cut out pieces around here, or give me a buzzz  !!

Later,  Cal


















On Fri, Jan 10, 2020 at 1:23 PM John Kohnen <jkohnen@...> wrote:
To build something like a Katydidn't, at 6 1/2 ft. long, it wouldn't be
much trouble to get the strips out of ordinary lumberyard wood, cutting
around the flaws. The strips don't need to be perfect anyway. The wood
is just a core. You'd put the bad spots between the good parts of the
adjacent strips, to keep the shape. It's also kosher to cut out the bad
spots and butt shorter strips together when putting them on the boat,
but kinda finicky with 1/4" strips, I imagine.

I've got a bead and cove router bit I'd loan to the Boathouse for a
strip build.

What was that Elmer's waterproof glue, Cal? I don't much like their
"Gorilla Glue" type polyurethane, and I haven't seen an Elmer's
"modified" PVA on the shelves. Lots of strip builders just use
carpenter's glue, even though it's not water resistant, because it's
easy to use. The boats survive fine because they don't live in the water
and it takes quite a while for moisture to get through the glass and
epoxy. Titebond II and III are as easy to use as carpenter's glue
though, so that's what I'd use.

Modern lightweight strip construction is really wood-cored composite
construction and doesn't work as intended without glass on both sides of
the core. For one thing, glassing just the outside of a light, frameless
(the glass acts as the frames) boat isn't a good idea, because if the
inside isn't thoroughly sealed the wood can move with changes in it's
moisture content, warping the boat out of shape. It's even recommended
not to wait very long between glassing the inside and outside because of
the risk of the wood moving. It's also the glass on the inside that does
almost all the work resisting knocks, bangs, and punctures from outside,
since glass is strong in tension, but week in compression. Best to do
what the designers say to do...

On 1/8/2020 5:56 PM, Electri-Cal wrote:
> First off, I did an 8 ft round bottom dink with old growth cedar cut to
> just over 5/ 16 ( to allow for some error ) pretty cost effective for a
> dink.  Used a couple dry 2 X 8 clear cedar boards picked from Jerrys,
> for grain that laid flat to bend correctly cause I could se it easy., 
>   NEW saw blade, cur all with a mask to avoid cedar dust, nasty stuff. 
> I ended up with enough to get me well under way,  Then used a small ball
> and router table to "C" out one side, sand the other to fit that radius,
> so the edges overlapped and rotated slightly as laid up over a couple
> bow, and stern frames L left as was, removed one center frame former. 
>   The bead and cove made alignment almost automatic, and was a pretty
> stiff hull.
>
> I glassed both sides, but it added unnecessary weight, outside is
> enough, in my experience,,  Maybe a floorboard inner pad for steeping
> aboard, or not.  I used elmers waterproof for everything except  glassed
> areas, I epoxied those.  Again I would use lighter than 3 oz. glass and
> less of it, the hull was really stronger than needed.
 > ...

--
John <jkohnen@...>
A learning experience is one of those things that say, "You know that
thing you just did? Don't do that." (Douglas Adams)






--
Thanks, I will reply to all mail as possible ---  Cal

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