MK9R
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| posted on 29/4/10 at 07:19 AM |
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Flexible fibreglass
I had a shunt (or 3) on track last weekend, and the bonnet survived pretty well, purely down to the fact that the exhaust had heated up the bonnet so
much it was very rubbery and flexible. When i came in the bonnet was all pushed up and crunched, but not cracked, as soon as i released the bonnet it
sprang back into its correct shape. Before anyone says anything, I know i need to add some heatshield here and its on the list to do. But this has got
me thinking, is there an additive or a special resin than means the fibreglass remains flexible. I have read that adding 5% acetone works, but
wondered if there is a specific resin or additive for sale out there and if anyone has used it.
The side of the bonnet was pushed in about 30cm when i returned into the paddock, but it just popped out! If it had been hard it would have shattered
to pieces
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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RazMan
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| posted on 29/4/10 at 07:59 AM |
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Generally speaking, the thinner the skin is, the more flexible it will be. Heat will also makes things move - leave your car in the direct sun and
things really start moving around. It usually stabilises again when it cools though.
Painters put plasticiser into their paint to make it less liable to cracking - maybe there is some sort of wax additive (like flow coat) for
fibreglass?
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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iank
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| posted on 29/4/10 at 08:14 AM |
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Flexibility will also depend on the lay-up, i.e. whether chopped strand or mat is used, and what orientation mat's are applied.
I'm sure both CFS and East Coast would be able to advise.
http://www.cfsnet.co.uk/
http://www.ecfibreglasssupplies.co.uk/
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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Neville Jones
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| posted on 29/4/10 at 08:30 AM |
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To answer your direct question re plasticisers; Yes, they are available, but rarely used as they affect the heat deflection temperature
(Tg)greatly.
Also, the low to average quality resins used by the vast majority of manufacturers, due to low price, have relatively low Tg's. Some as low as
45~50c. The good poly resins can be as high as 85~90c, but are twice the price and not far short of the price of the low end epoxies, which would be
the preferred resin in this application.
Cheers,
Nev.
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britishtrident
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| posted on 29/4/10 at 10:29 AM |
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The resin matrix gets progressively stiffer/harder/more brittle as it ages.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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suparuss
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| posted on 1/5/10 at 08:44 PM |
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ive done all my bodywork with normal loyds approved resin (ie- not cheap remixed stuff) and a lamination of about 3.5mm with alternating csm and twill
weave. when i chop any excess off the panels, say a 2" wide strip 400mm long, i can bend it right round so the ends touch each other then it
springs back, takes a fair bit of humph the break fibreglass if it is done properly, not need for additives.
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