All Fiberglass teardrop design opinions?

[WesGrimes]

Great site you guys have here. This is my first time posting, and I am new to the Teardrop world.

I am planning to build a 5'x10' Teardrop using all FRP construction.
My plan is to build a female mold out of 2x4s particle board and hardboard.
Then layup the mold as follows:
3 layers of PVA
2 layers of Gelcoat
2 layers of 1.5oz CSM
1 Layer of 24oz woven roving
1 layer of of 1.5oz CSM
1 Layer of 24oz woven roving

I will be using general purpose polyester laminating resin.

The wall thickness should be about 1/8" and about 2lbs per sq ft.
I will glass some 1 1/2" wood blocks on the inside to attach an inside wall of hardboard to. The wall cavities will be filled with 2lb mix and pour PU Foam.

The cost of the FRP materials will be around $600, but in return I believe I will have a very light, strong, watertight, well insulated tear...

Has anyone tried anything like this? Any suggestions/opinions?
Overkill? Too weak? Crazy?...

Thanks!
Wes

[Gerdo]

You may want to change the title of your thread to "Fiberglass".

FRP may be the proper term but here most of us are thinking Filon when we see FRP.

I used a combo of FRP (Filon) and FRP (Fiberglass reinforced plywood)

Sorry, other than that I can't help you with a "fiberglass" build up. There are wuite a few who have tho.

Welcome to the world of Teardrops.

[WesGrimes]

Thanks Gerdo,

Good point. FRP means fiber reinforced plastic to me, but might mean different things to different people...

[mallymal]

Just my 5c worth....

I would imagine it would take a particular thought process to mentally reverse every aspect of the tear as you build the mold. And remember, it's not just the overall shape you have to visualise 'inside out' , you also have to design in 'returns' for the door opening and hatch edges etc.

If you happen to HAVE that type of brain, then go for it, but there's absolutely no room for adjustment. Once that mold is made, and you've painted on the gelcoat, you're committed.

Whereas you build in timber, and you can constantly adapt & adjust as you go along and find problems you haden't anticipated.

Good luck whatver you do, and enjoy your build.

Anyhoo, what do I know.... months of browsing and still no definite profile designed!!!

[kennyrayandersen]

I suspect that you will want to reinforce some local areas where the axles attach with some plywood and also you made no mention as to how you are thinking to attach the body to the trailer, or what type of trailer you were thinking of using. The local attach points are another area that is likely to need some type of reinforcement.

Your technique doesn't sound terrible for the top or maybe even the walls, but after having modeled the floor considering a foam core I think with a solid laminate only in the floor you would either be quite heavy, or structurally deficient.

Checkout the jmedclay thread on how he intends to build his tear, which I think seems a more reasonable approach. It really better or have some kind of core to both insulate and to carry the shear load between the two face sheets. Also, the solid laminate on it's own is not a particularly good insulator.

Also, There are some real challenges to making a female mold, mallymal's 3D concerns aside. Usually, you have to provide some sort of draft so that you can get the finished part out of the mold, or the mold has to be able to split in a way that allows separation.

I suspect that the reason you are contemplating a female mold it to provide a smooth exterior surface, no? I think there would be other ways of doing that (additional coats of epoxy and sanding etc (check on the composite boat building sites which often build using male tooling)). For me, I think building the composite panels separately would be much easier and even considering mixing some plywood (which is in it's own right a composite) and foam with the fiberglass cloth to achieve a much more robust and easier to build body.

It's not that you can't do it that way...