advice to lay fiberglass on plastic hatch

[rufus2000]

Hello, I have a proboat miss geico v1 plastic hatch that I want to strenghten (not sure if it's acrylic).

I have z-poxy resin and fiberglass cloth I could use.

Was hoping for some advise on the best way to do it, perhaps just resin or should I apply the fiberglass too?

The fb cloth I have is a medium 2 oz (57g) and also a heavy 6 oz.

Looking forward to your recommendations on what to use since I hear those are a bit bristle and replacements are now discontinued. thanks.

[Old School]

West System G-flex resin is designed to apply fibreglass or carbon fibre cloth over "difficult" plastics like ABS. It is relatively expensive compared to typical resin. The area is scuffed with around an 80 grit paper and then wiped with acetone prior applying the resin mix. G-flex sticks very well if applied this way. I have inlay ed several ABS hulls with CF cloth and suffered no delamination. If you apply just the resin you have then you impart no strength to the hatch as the cloth is needed (think concrete without the steel reinforcing bars). G-flex allows minute flex once cured so does not tend to be brittle if the part is flexed leading to delamination.

[rufus2000]

Thanks for your reply. It might be a bit difficult to get West System in my area. Z-poxy says it should work with most plastics but does not specify if it's good for ABS... Might try it.

Still, I have another idea: Could I use expanding foam? That boat has a tupperware like lid that goes below the hatch. I'm thinking that I could drill a small hole at the top of the hatch and mask the tupperware lid with tape (basically the hatch becomes a mold) then I pour the expanding foam into it. Provided the foam bonds with the inside plastic of the hatch and does not eat it, it could be good for strenghten it. Do you guys think it could work? or is this a silly idea.

[nocebo]

I think the fiberglass would be your best bet. As long as you scuff up the surface you should get a decent mechanical bond with the plastic. The fiberglass provides the strength, the resin is really just to hold it in place.

Probably wouldnt go the expanding foam, sometimes they can continue to expand in confined spaces and blow your boat apart. If you do go down the expanding foam route, I would go for the two part "floatation foam" rather than the construction foam used in houses.

[rufus2000]

Thanks for the heads up regarding the expanding foam. I'll go with the fiberglass then. Still have to determine which one to use. I have the heavy one (6oz), should I lay two of those or more or is just one layer is ok? thanks

[nocebo]

One layer is more than likely to be ok - its strong stuff and a hatch isnt really a structural member. You can always add another later later on if its too flimsy, just make sure to scratch up the surface with some sandpaper first. One thing to watch out for is not to use too much epoxy, only adds weight and not strength

[rufus2000]

Great tips, really appreciate it. Will do as you mention. Thanks!