Thread: Fibreglass over plywood.

My experience is all to do with building wooden boats, which covers what you're attempting and I'm happy to share my experience with you. However, I'd suggest you become a member of the Woodworking Forums of which the boat building is just a small subset. You WILL find other nutters involved in your particular insanity and best of all, it's an Australian forum so you don't have to speak 'foreign'. Seriously, you'll find a niche on there that's doing what you want to do. Failing that, ask me.

As Crackers says, what you are suggesting has been done by a lot of boat builders.

It is also used to construct stitch and glue canoes and kayaks.

There are a couple of issues you need to think about. Is the glass and resin there mainly to protect the ply from the elements and from minor scratches or is it intended to add significantly to the structural integrity of the camper?

If it is mainly to protect the ply, then quite light glass, maybe about 85gsm would probably be best. Remember that for every gram of glass, you will have about 2 grams of resin and that heavier cloth will need a greater number of extra coats to fill the weave and achieve a smooth surface.

If the glass is intended to add a significant amount of extra strength, then glass on both sides is much more than twice as strong as glass on one side. Also if the glass is used on both sides, then I would think that 12mm ply is much heavier than you need. You might need very little in the way of frames inside and/or you might only need 4mm ply.

You might need to get some extra information about different types of resin. Polyester is cheap but inferior; vinyl ester has some advantages and disadvantages; epoxy is more expensive, but a superior product. Epoxy needs a varnish or polyurethane or paint to protect it from UV light.
http://www.ncspldc.org/ncspldc/topics/epoxy_resin.htm

My experience with a similar technique involves kayaks built from 4 or 5 mm thick strips of timber glued together and glassed on both sides with 85 or 125 gsm glass, but as crackers said, there are plenty of people on the Woodwork Forum that have built small boats and there are almost certainly people who have built something similar to your camper idea.

another vote for the woodwork forum

Woodwork Forums

I wouldn't use glass unless your needing it for strengthening. It's good for joining corners. If you want to protect the end grain on ply you can use Evadure or thin Epoxy but will need UV protection.

Glass tends to be rigid. Rot proof ply is also an option as water doesn't affect it.
Joins using aluminium extrusions and Mastic may be quicker, stronger and
Look more professional. It's how truck bodies are fabricated.

Post photos of your build.