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Re: Fiberglass bonded to body question

To: Fred Talmadge <fredtal@industryinet.com>, british-cars@autox.team.net
Subject: Re: Fiberglass bonded to body question
From: Barney Gaylord <barneymg@ntsource.com>
Date: Sun, 16 Jun 2002 20:11:32 -0500
At 09:16 AM 6/16/02 -0500, Fred Talmadge wrote:
>On my Elva Courier the fiberglass body is bonded to the steel 
>chassis.  How was this done?

I believe what you have is here and there a metal part (maybe a flat plate) 
laminated into the fiberglass.  I would rough up most or the surface of 
such a metal part with maybe 30-grit sandpaper, slop some of the mixed 
plastic resin on the part to wet it first, and then lay the fiberglass on 
and around it using either random mat of woven cloth fiberglass, and enough 
of the mixed plastic resin to saturate the material and eliminate all air 
pockets (commonly applied with a brush).  Build the fiberglass material to 
sufficient thickness to provide the required structural integrity.

>Can a guy (not neccesarily me) do it in his garage?

Yep.

>And finally how do you remove the body from the chassis?

These assemblies are generally not meant to ever be disassembeld.  However, 
if you insist, ....
Cut, grind and/or sand the fiberglass material off of the metal part.  To 
reassemble later, follow proceedure above to laminate the part back into 
the fiberglass body.

For structural parts (like suspension mounting points for instance) it 
takes some experience or some understanding of the general properties 
(strength and crack resistance) of the fiberglass material in order to 
determine how much material is required (and where) to provide the desired 
strength.  If you have a prior example of a successful assembly, you might 
make some sketches and notes prior to disassembling it, and then do you 
best to reproduce the same arrangement later for reassembly.

When in doubt, add a little more fiberglass for increased strength.  If the 
additional weight bothers you, and you are shooting for the most minimal 
weight reasonable, then you might consult an expert in this 
field.  Fiberglass boat builders come to mind.  Also possibly a body shop 
that specializes in repair of fiberglass car bodies.

Lots of fiberglass bodied cars have a removeable body just dropped onto a 
structural fame, which is much different thay having the fiberglass 
structurally holding the suspension parts with out any other 
framework.  One such car that I am fairly familiar with is the Lotus Elite 
(1960's vintage?) which has a fiberglass body shell with localized metal 
plates laminated into the body for attachment of the suspension parts, and 
no metal framework connecting the four corners of the car.  I seem to 
recall that car was very light, like maybe 1200 pounds complete.  It is 
also a Coupe body type with a hardtop roof, so the complete shell like a 
closed box for better rigidity, and even the roof is providing part of the 
structural stiffness of the chassis.  Think of it as a stressed skin 
assembly similar to modern airplanes where the shell itself is reinforced 
in critical points to attach structural parts.  There is more to this than 
simply providing a strong joint for the attached part.  The body shell of 
the car must be strong enough to hold and resist and transmit the 
mechanical loads of the moving suspension parts.

I am not very familiar with open top cars of this type where all of the 
structural rigidity must come from the floor pan and sidewalls.  But I 
guess if I was to race one regularly I might learn this stuff quickly (like 
the first time it was involved in a serious shunt).

Barney Gaylord
1958 MGA with an attitude
http://www.ntsource.com/~barneymg

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