How heat resistant is fibreglass?
I'm running a turbo not far from the bonnet, anyone have experiences of this what they combat heat with turbo blanket? Or reflective heat stuff
on underside of bonnet?
Or cut a hole above the turbo and mesh it over
id give it plenty of room. even sunlight on a hot day can mis-shape a bonnet
Haha,
Best do something about this then
The flash point is very high but it softens significantly earlier.
Some Fury's have set fire to the exhaust side pod/sill. As far as I know the exhausts in question were wrapped which keeps the gas temp higher. I
also suspect they then had a crack blowing exhaust direct onto the GRP as Welderman on here had a hole/crack in his exhaust almost set fire to his
side pod/sill.
I've heard of one that got road chipping collected in the sill, that retained enough heat exhaust to blister the GRP and seen another smoking
after an "enthusiastic" run up the col du Turini, and a Pheonix bonnet (race weight) fold in half when being opened, after being left in the
sun over lunch in Italy.
Heat proof mat and good ventilation are the best solution. In particular think about ventilation and air flow when stationary as thats when the temp
really rises. My sill is open at both ends but got very hot when stopped. Opening up the bottom made a huge difference as then, fresh cool air came in
the bottom as the hot rose and exited the ends, giving a through flow that didn't exist with just the open ends.
Heatproof mat (CBS stuff is cheap and works well, get their adhesive too as you don't want to skimp on the glue).
I have a heatshield and mat on the underside of the bonnet. Before the heatproof mat the bonnet got to 95degC (measured with one of those IR heat
things after only a gentle run). It is quite old so was flexible but didn't deform. Newer fibreglass starts to get wiffy at those
temperatures.
Seems good now, although my aluminium heat shield (just shown at bottom) keeps breaking free of the manifold from vibration.
Matt
My locost solution was to use a piece of fire resistant soffit board (kinda like asbestos board) attached to the ex. manifold by two of those big
springy tool clips but standing off from it by packing them out with some of the board.
That stops the ex. heat rising directly onto the underside of the g/f bonnet.
Pics if you want them.
HTH.
Cheers, Pewe10 
Does depend on the resin you are using and if you have actually had it post cured also.....
Most 'GRP' tends to use polyester as the matrix. Polyester is at the bottom of the scale in terms of properties - but due to this, usually
the laminate will be thicker to increase strength. Adding thickness and mass helps dissipate the heat better. You can buy flame retardant polyester
and high heat versions, but if you wanted better over all performance I would move to a different matrix type. Cost does play a big part though....
Something i am working on at the moment for the locost is going to be made from Vinylester to improve the properties as mentioned above.
If you use as suggested a heat shield and give as much space as possible then i would expect your bonnet to be ok.
Rob
ill post a pic tonight of how it looks,
going to have to sort something anyway i want to keep away from wrapping or using a turbo blanked too if im honest as i dont think they are good in
the long run
thanks
Seen the pic - it's way close, you do need to do something about it, else you'll be having a melty car! (IMO)
quote:
Originally posted by matt_gsxr
Heatproof mat (CBS stuff is cheap and works well, get their adhesive too as you don't want to skimp on the glue).
I have a heatshield and mat on the underside of the bonnet. Before the heatproof mat the bonnet got to 95degC (measured with one of those IR heat things after only a gentle run). It is quite old so was flexible but didn't deform. Newer fibreglass starts to get wiffy at those temperatures.
Seems good now, although my aluminium heat shield (just shown at bottom) keeps breaking free of the manifold from vibration.
Matt
here is what im up against, engine does not run yet but will in the next few weeks
bonnet on
Interesting thing about fibreglass - when it gets hot enough it will burn, and once alight it's almost impossible to extinguish.
Wow, that's way too close for comfort!
Reckon you'd be better cutting a hole in the g/f around that area and putting a mesh bulge over the top.
Having run turbo tin-tops for years they really do throw out a huge amount of heat.
HTH.
Cheers, Pewe10
i would cut a hole in the bonnet and mesh it
then alot of the heat will escape upwards
quote:
Originally posted by tomgregory2000
i would cut a hole in the bonnet and mesh it
then alot of the heat will escape upwards
quote:
Originally posted by Macbeast
Interesting thing about fibreglass - when it gets hot enough it will burn, and once alight it's almost impossible to extinguish.
quote:
Originally posted by beaver34
quote:
Originally posted by matt_gsxr
Heatproof mat (CBS stuff is cheap and works well, get their adhesive too as you don't want to skimp on the glue).
I have a heatshield and mat on the underside of the bonnet. Before the heatproof mat the bonnet got to 95degC (measured with one of those IR heat things after only a gentle run). It is quite old so was flexible but didn't deform. Newer fibreglass starts to get wiffy at those temperatures.
Seems good now, although my aluminium heat shield (just shown at bottom) keeps breaking free of the manifold from vibration.
Matt
Matt have you a pic of the turbo and where it sits inline with the bodywork
thanks
Thanks,
Think I'll look at getting some of the mating for the bonnet, it's not cheap for the very high temp stuff but it's better than a new
bonnet or car