Re: [PSUBS-MAILIST] Composites Question

[Ed Greany <crest25@attglobal.net>]

Hi Chris,

I once owned a fiberglass manufacturing business building fiberglass
boats which were all hand layup. We cured the resin at room temperature
(is there another way?) Is there something specific I can help you with
in the process? I'm not sure what you need unless it is simply
literature or DIY books of fiberglass work. If that is the case, many
automotive repair manuals and auto restoration books cover the
subjectmatter pretty good.

Basically, there is mat, cloth, resin, and catalyst. The mat and cloth
comes in various weights. The mat is for regidity - the heavier the
weight, the stiffer the final product.  The cloth is for flexibility and
allows more bending rather than breaking as cloth does. The best is a
combination of both. Two layers of mat and one layer of cloth works best
for me.

The resin is what you saturate the cloth and mat with. Saturate the mat
layers (one at a time) well then lay the cloth on top and do not apply
resin directly to the cloth but allow the cloth to soak up the resin
from the mat. This gives a nice finished product without a shiny glossy
cloth finish caused by too much resin. The catalyst is what creates the
resin to chemically react and giving off heat and hardens. The more
catalyst, the more heat and the faster it "cures".

Fiberglass is like building a car but in reverse. Auto building works
like this:
First, Detroit takes a frame, adds a body to it, paints it, then
polishes it spotless.

Boat/Sub building in fiberglass works just the reverse. First polish it
spotless, then paint it, then add the body, then finally add the frame.
HUH, you say? Let me explain.

You will first need a mold. A mold is built using a "plug" or an exact
of the final product. I won't go there for this discussion.

Take the mold and Polish it shiny. Remember? This was the final step
with autobuilding. Polish it with release wax many coats. You DON'T want
the resin to stick in the mold. It ruins the product AND the mold.
Now paint it with gel coat. Gel Coat is like a fiberglass paint. The
finish is exactly equal to the amount of shine you have after polishing
so polishing is the most important step.

After the gel coat, apply the mat and then the cloth using resin. After
it cures (from 3 minutes to about 1 hour depending on the temperature
and/or weather) using resin as glue, position wood as a frame to the
parts that will require reinforcement for fiberglass is flexible and
doesn't stand up well without support of some kind.

You now have the entire process. Save your money on the book. Go out and
but resin but be educated for there are different types of resin. You
don't want casting resin.

Good luck. Hope this was helpful and answered yoru question.

Ed Greany, STS2-(SS)

Chris Crouch wrote:
> 
> Hi all, I have been lurking in the shadows for a while and am starting an
> unrelated project but I was hoping someone here might be able to help.
> Does anyone know of some good practical literature on constructing a
> composite mold?
> In particular resins to be used for the mold surface for a hand layup with a
> room temperature cure?
> 
> Thanks in advanced
> 
> Chris Crouch