Date: Sat, 15 Feb 1997 14:04:02 -0500
From: Bill Low <billow@capecod.net>
To: baidarka@lists.intelenet.net
Subject: Re: Skin boat coverings
Russell wrote:
>
> I've pretty much decided to build the boat described in Wolfgang
> Brinck's book but I have one major concern....I've read the postings
> sent here over the past few days and I've seen some comments on the
> nylon skin STRETCHING after the boat is put in the water...has ANYONE
> got a definite solution for this?..how about pre stretching the skin
> before sewing it on the frame?....maybe wetting the material, then
> stretching it on some sort of frame and keeping it there till it
> dries...anyone know if this might help the stretching problem...I've
> thought of buying a piece of nylon and testing this idea, but if there
> is anyone that KNOWS if this will (or not) work I'd appreciate an
> answer...Russell
Since this has been a bug-a-boo for me and I have been trying to get a
definitive answer myself so I'll throw in my 3 cents.
My first boat was nylon. I tried the wetting the skin before sewing. I
don't think you can put it on to tight. My skin was wet during sewing so
it would shrink tight. It did. The nylon does absorb water and it will
expand. In fact you have to dry it before you injection mold nylon. It
does shrink on drying but it has a limit on how far. It takes a set but
it will not crack ribs or anything else. (Personal experience) It looks
great after sewing and coating. I used polyurethane and it has held up
very well.
Now the problem! As soon as it hit the water the nylon absorbed more
moisture and went slack. There are wrinkles. One rug rat made the
comment it looked like a prune. If left in the hot sun it does begin to
tighten up. If left in a dry heated basement in northern Maine all
winter it returns to its initial shape only to reabsorb and slacken when
it hits the water.
I tried coating the inside of the boat with polyurethane to seal it. To
no avail.
It looks a little weird but it works fine. It is now three years old and
is used regularly. No problems
I have not used canvas so I cannot comment on it. I now use a polyester
material available from George Dyson. It is more difficult to sew but I
am very satisfied with the results. Based on the look, strength and
finish I would not change to back to nylon. Even though nylon is much
much easier to work with.
It has been suggested that heating the nylon after sewing with a steam
iron will set the nylon and reduce the effect. I have some friends who
are going to be building two boats with nylon this spring. I have
advised them to wet during sewing, as tight as possible and then steam
heat before coating. We’ll see how that works
Bill Low