In article .com,
wrote:

Hi,
I'm trying to make a board similar to a skateboard. I'd like to
use 1/4" plywood but 1/2" would work too. The problem is that it's not
strong enough to support a person. I've heard of using fiberglass with
an epoxy/resin that will drastically increase the strength of whatever
you put it on. I was wondering if anyone could give me some advice on
how and what to use to strengthen wood.

Check out http://www.epoxyworks.com/, specifically the article titled,
'Fortifying a spare-parts "Scootboard"'.

All of the strength is in the fiberglass (or, in this case, carbon fiber)
skins. A common boatbuilding technique is to laminate fiberglass top and
bottom skins over balsa. The balsa provides no strength by itself; it just
holds the two skins apart. Think torsion box.