stress fractures/cracks spreading in fibreglass panals
daz928sb - 17/7/15 at 10:55 AM
hi, i just wondered if anybody has this problem!
i have a mac1 zx10r worx which the bodywork ( bonnet ) and nose cone ect seem to be spreading with splits ect.
i have even attempted to wrap the bonnet to maybe stop the spraed but you can obviously see them through the wrap!
i guess its because of the vibration from the engine and obviously a bit of the hard set-up suspension!
its doing my head in!
i guess i will eventually have to get a new bonnet and cone but wondered how this can be prevented and also repaired in
some places.
has anybody else experienced this??
loggyboy - 17/7/15 at 10:56 AM
Just the Gel coat cracking?
Charlie_Zetec - 17/7/15 at 11:39 AM
Sounds to me like it's just the gelcoat cracking. You can repair yourself, or get someone to do it, it's not a massive job. But
understanding why this has happened is a bit difficult without knowing the materials used in the construction of the bodywork ie. the type of glass,
weight, resin etc.
My guess is that it's a chopped strand glass with gelcoat outer, made using polyester resin. You can fix by using epoxy resin (polyester
won't stick to polyester) either mixed with colour pigment to try and colour match, or have it filled and sprayed.
jossey - 17/7/15 at 05:54 PM
Drill a tiny hole where it ends to stop it spreading firstly. Just 1mm drill bit will do. Repairing is then much easier
daz928sb - 27/7/15 at 12:05 AM
Thankyou gents for the replys
twybrow - 27/7/15 at 12:41 AM
quote:
Originally posted by Charlie_Zetec
Sounds to me like it's just the gelcoat cracking. You can repair yourself, or get someone to do it, it's not a massive job. But
understanding why this has happened is a bit difficult without knowing the materials used in the construction of the bodywork ie. the type of glass,
weight, resin etc.
My guess is that it's a chopped strand glass with gelcoat outer, made using polyester resin. You can fix by using epoxy resin (polyester
won't stick to polyester) either mixed with colour pigment to try and colour match, or have it filled and sprayed.
Nearly right. Polyester will stick to polyester, but only as a keyed surface (mechanical adhesion) - when laying up fresh you get chemical adhesion.
Polyester won't stick to epoxy but epoxy will stick to polyester. Otherwise I agree!
Charlie_Zetec - 27/7/15 at 11:29 AM
quote:
Originally posted by twybrow
quote:
Originally posted by Charlie_Zetec
Sounds to me like it's just the gelcoat cracking. You can repair yourself, or get someone to do it, it's not a massive job. But
understanding why this has happened is a bit difficult without knowing the materials used in the construction of the bodywork ie. the type of glass,
weight, resin etc.
My guess is that it's a chopped strand glass with gelcoat outer, made using polyester resin. You can fix by using epoxy resin (polyester
won't stick to polyester) either mixed with colour pigment to try and colour match, or have it filled and sprayed.
Nearly right. Polyester will stick to polyester, but only as a keyed surface (mechanical adhesion) - when laying up fresh you get chemical adhesion.
Polyester won't stick to epoxy but epoxy will stick to polyester. Otherwise I agree!
Correct - but to try and get a properly keyed up surface on polyester and then fill/smooth over is incredibly difficult! I've tried it on rigid
structures and it's a PITA, so on 7 bodywork I'd say it was *near on* impossible to make good a repair that will last, hence the use of
epoxy for a better finish.
Out of curiosity, do you work with GRP/fibreglass professionally then, or just dabble when necessary?
twybrow - 4/8/15 at 06:08 PM
It is my job. I lead a team for one of the largest suppliers of composite materials, with a dedicated focus alupon automotive applications. Name a F1
team, or supercar and chances are my team will be behind it.