Zonda Carbon hull repair

[Nismo400rgtr]

Hello everyone,

I'm not proud to admit I crashed my Zonda this weekend while slowing from a full speed run into a rubber buoy. I will say I am impressed with the strength of the carbon fiber. I have some 2 part marine foam filling the front of the boat as well so perhaps that helped in reducing the damage. It just appears to be cracks in the clear gel coating of the exterior of the hull. I've never been in this situation before and have no idea how to fix it. Or if I even should do anything? Here's some photos so those of you with experience can decipher.

103736
Left front lower side of sponson
103737
This is a chip right off the tip
103738
Bottom front left sponson
103739
Bottom front left sponson

All cracks can be felt by hand but there are no risen edges. Thanks in advance for the help.

[grsboats]

I'm sorry for your bad luck but the best way to make sure these cracks are repaired is to laminate carbon fiber from the inside,not an easy task but it can be done with some experience...the problem is that you filled the front with two part foam.quick solution is to use epoxy glue 30min on the cracks just to make sure there's no water leaks. Gill

[Nismo400rgtr]

Thanks for the reply Gill. What exactly does re-laminating carbon fiber entail? With the foam, as you mentioned, I doubt it'd be possible. Guess I'll just have to repair from the exterior, hope for the best and try and avoid objects on the water ;).

[blowNover]

Please someone that is more experienced chime in here if I am wrong. But won't acetone or something similar turn the foam into a slimy liquid. If that's true you can in theory remove the foam.

[twissted]

In your case, I would go to the hardware store and buy some epoxy spray paint and mask off the damaged areas then match the other side and paint light coats until you have a about 6 light coats that will seal the hull. Then do a water test in a tub' then drive it like you stole it. Your foam will have to make do. you could take the foam out as best as you can and redo the foam as it will help make stronger again.

[grsboats]

BlowNover depends on the type of foam but with the two part marine there is nothing that makes it liquid.The solution is work carefully from the outside using a good slow set epoxy glue that can be warmed to better penetrate the cracks .The foam in the inside is structural so with patience this kind of injury can be repaired with no future issues.Gill

[grsboats]

Re laminate means aplly one or two laywers of carbon fiber cloth with epoxy resin over the cracks to seal and reinforce the affected áreas .How much foam you have in the boat? Sometimes is better try to remove it to have a good repair.Gill

[Nismo400rgtr]

Re laminate means aplly one or two laywers of carbon fiber cloth with epoxy resin over the cracks to seal and reinforce the affected áreas .How much foam you have in the boat? Sometimes is better try to remove it to have a good repair.Gill

That's what I thought -the lamination- just double checking. Just the very front of the boat has foam. Maybe about 8 inches towards center from the front tips. I think about 80ml of total foam used (in liquid form obviously).

If I was to go the route with an exterior fix, as you mentioned with warming the hull. What type of epoxy would work best? I have some Zpoxy PT-40 on hand, but I'm not sure if that's best.

[Fella1340]

Hello there, I have never made this type of repair on a RC boat but on the full size boats I would the same epoxy resin that the hull was originally built with. You can use the west system epoxy resin or another high quality resin. Its quite runny. Fill the cracked areas with the resin from the out side, let it set up and sand and polish out. If your unable to get at it from the inside this is the route I would go. When its all said and done the repair should be barely noticeable. The resin will be able to flex withe rest of the boat. Just my 2 cents worth. If you go the standard epoxy route find the slowest curing type you can find. I find the quick set epoxies end up being quite brittle in the long run. Like I said I have never done this on RC boat, just the big ones. Jeff

[grsboats]

Well considering that foam expansion is about 30X you can guess how far it went in the hull.Yes use the same epoxy resin of the boat is a good idea but my guess is that the Zonda is made from poliéster.Anyway you can use a good slow cure epoxy glue to solve this issue.The Zpoxy PT 40 is not my favorite product.If you can get West System resin you will have the best product in your hands.Gill

[Nismo400rgtr]

Thanks gentleman.

I've never made this sort of repair before and I'd like to keep it barely noticeable. After I let the epoxy set, what grit sandpaper should I use to smooth the texture? Wet sand correct? And then what product to polish?

[grsboats]

Take care with epoxy as its hard to sand so be gentle with your repairs...try to use tape to isolate around the cracks.You can use wet sandpaper 600 to start and go to 1000,1200 and finish with 1500.To polish any good paste from 3M will work.Gill