"two_k2003" wrote in message
om...
Hi All -

I occasionally come across the phrase "lay-up" when I read about
kayak construction - usually having to do with fiberglass boats.

Typically it is in the context of problems having to do with a
particular boat's "lay-up".

Could someone please define that term for me?
And what are the usual problems associated with it?

Thanks,
TwoK

Lay-up refers to the actual physical process of hand "laying" the layers of
reinforcing material into or onto a mold used in the construction of
composite (fiberglass, kevlar) products. It is a term used almost
universally by people that make all types of composite products by means of
hand laying the matt or woven cloth in place. Another method of
construction is referred to as a "spray-up". That's when small strands or
pieces of the reinforcing material are blown or sprayed into a mold rather
than laid in by hand in sheets of matt or woven cloth form.

Problems with lay-up can range from negative characteristics such as
extremes (one way or another) in weight to inconsistency from one part
sample to another to faulty construction such as too much cloth and not
enough of the resin or epoxy that binds it all together or vice-versa.

The layer that makes all of this yucky stuff look nice and resist damage is
called the gel coat. Sometimes the gel coat, which also gives the finished
part its color, can have pin holes or bubbles or tiny patterns of cracks
called crazing. Defects in the lay-up are often also referred to as
problems with the lay-up.

I hope this information is helpful to your understanding. I'm getting a
headache and itchy all over just thinking about it!

DV