fix carbon bonnet?
08-02-2011, 10:05 AM
#1
fix carbon bonnet?
Hi folks...lucky enough to acquire a Carbon Fibre bonnet via evil bay, however upon delivery 3 corners have taken a slight hit and the main inner structure has a hairline crack on one side. It looks ok but these issues need to be fixed for my standards. So, is it repairable with some sort of resin/ glue or do i need to open a hornets nest of blame?
08-02-2011, 11:09 AM
#2
Burning Brakes
Well... whenever I had issues with bycicle frames that had a crack in the frame it was replaced... and never repaired.
I wonder what Boeing and Airbus will be suggesting for their carbon fibre parts.
Anyway: I would have it replaced or get my money back.
I wonder what Boeing and Airbus will be suggesting for their carbon fibre parts.
Anyway: I would have it replaced or get my money back.
08-02-2011, 12:42 PM
#3
Nordschleife Master
Seems the least to do is to drill a stop-crack hole at the end of any crack.
The corners I'd glob on epoxy (+ chopped fiber if the injury was more than dinky), then blend/sand smooth to match adjoining surfaces and repaint.
Further, it seems to me the bonnet is a non-stressed part, so you won't be looking to regain it's full-thickness strength at these injury sights.
I'd check with folks, here, on how to cosmetically patch cracks on composite parts.
...Absent such advice -- and if I had to get it done -- I'd probably grind out a shallow, broad valley along the crack's length (both sides) and throw into it some epoxy + carbon cloth or chopped carbon, cure, sand smooth, (gel coat?), repaint and hope for the best.
(And buy my wife some flowers, cuz black ground carbon dust is likely going to creep everywhere from the garage into the house...)
For a stressed part (e.g. aircraft part), repairs become a more meticulous PITA.
Essentially you grind down in a step-wise fashion, layer by layer, creating broad steps of each layer from one side, (or from both sides to meet in the middle).
Then you lay up prepreg patches to fill in each layer's step, vacuum bag + heat blankets till cured. (The last surface layer patch[s] covers all those beneath and extends well beyond the last step's edge.)
Blend smooth(er), prep surface for repaint.
With steps sized correctly, the repair is as strong as adjacent material.
(And I'd have to be well in the bottle to imagine a hood/bonnet ever demanding such strong repair.)
The corners I'd glob on epoxy (+ chopped fiber if the injury was more than dinky), then blend/sand smooth to match adjoining surfaces and repaint.
Further, it seems to me the bonnet is a non-stressed part, so you won't be looking to regain it's full-thickness strength at these injury sights.
I'd check with folks, here, on how to cosmetically patch cracks on composite parts.
...Absent such advice -- and if I had to get it done -- I'd probably grind out a shallow, broad valley along the crack's length (both sides) and throw into it some epoxy + carbon cloth or chopped carbon, cure, sand smooth, (gel coat?), repaint and hope for the best.
(And buy my wife some flowers, cuz black ground carbon dust is likely going to creep everywhere from the garage into the house...)
For a stressed part (e.g. aircraft part), repairs become a more meticulous PITA.
Essentially you grind down in a step-wise fashion, layer by layer, creating broad steps of each layer from one side, (or from both sides to meet in the middle).
Then you lay up prepreg patches to fill in each layer's step, vacuum bag + heat blankets till cured. (The last surface layer patch[s] covers all those beneath and extends well beyond the last step's edge.)
Blend smooth(er), prep surface for repaint.
With steps sized correctly, the repair is as strong as adjacent material.
(And I'd have to be well in the bottle to imagine a hood/bonnet ever demanding such strong repair.)
Last edited by elbeee964; 08-02-2011 at 12:57 PM.
08-02-2011, 05:17 PM
#4
Thanks for the advice guys. good to know its a non-stressed part...could air get under it at speed and cause it to bend at the crack potentially or is that a bit extreme...i.e. the seals work! I can potentially lay a patch of carbon over it but it seems that would also cost me flower money! Ill see if i can reach an agreement with the PO.