NAC: fiberglass fabrication

Mon Mar 21 21:57:54 EST 2005

> From: Igor Kessel <KBATPO at>
> Subject: NAC: fiberglass fabrication
> To: Audi S-list <s-car-list at>, Audi Q-list
>   <quattro at>
> Message-ID: <423F73B7.7000807 at>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> Folks,
> can any of you either recommend the literature or better yet personally 
> teach one very receptive (and humble too, I might add :) ) DIY quick 
> learner and Audi fanatic how to fabricate laminated fibreglass panels? I 
> will supply all the beer and junk food that the intensive thought 
> process will require.
The usual method is to make up a form/mold, smaller items have molds cast in 
plaster. Larger molds are made of plywood, or similar, with a plaster liner to 
capture the mold.The form is them coated with a "release agent". This is 
readily available, certainly in art supply stores. The fiberglass cloth (getting 
harder to find in automotive shops in "woven", cloth like, form) is then soaked 
in resin (with catalyst/hardner) and laid in the form. Multiple layers are 
then added until the desired thickness is obtained. Art supply stores can also 
supply coloring agents. If the finished surface is not as desired (there will 
be small voids) the surface can be "painted" with thinned resin (there is a 
"thinner" available. Can't think of a brand name. Once again this is an art 
supply, or woodworking store, product. Auto supply stores won't carry it) and then 
sanded to the desired finish. Wes Products makes very nice stuff, including 
the cloth. Some of their cloth is too thin for automotive use without a lot of 
layers. I have it on my rowing shell, it disappears under a coat of clear 
resin/varnish. This would be found at woodworking or marine supply stores. Nuthin 
to it.

Most modern fiberglass pieces are built up with "chopper guns". Fiberglass 
strands, mixed with catalyzed resin, are shot under pressure into the molds. The 
gun "chops" the strands. Similar to a spray painting technique. Not practical 
for DIY.

Tom Faust

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