> This is a little off topic but I will ask anyway. I'am helping a friend's
> son with his pickup truck. He has made a "flush with the rails"
> Tonneau cover for the bed of his fancy pickup. He used aluminum channel
> around the primeter of the box and used lauan ply to slide into the
> channel, the underside is reenforced with joists. He wants to cover the
> plywood with glass- epoxy (my idea) and paint it the same color as the
> truck(orange) or black

> The question is: will the sun get the dark colored epoxied-glassed plywood
> too hot and destroy the epoxy? Are there any pigments that will color the
> epoxy that look as good as paint? and finally will the epoxy need to have
> UV protection if a pigment is used instead of paint?

> Thanks,

> Larry C.

First answers to your questions: Will it get too hot and destroy the epoxy? Maybe if you park it in Death Valley it MIGHT get hot enough to do some damage to the top, but I think that would be the least of your problems. Long before then the interior of that mobile greenhouse you refer to as the `cab` could hit temperatures hot enough to melt the plastic on the steering wheel, and turn the plastic dashboard into a puddle. Driving in high heat would provide enough airflow to cool things. Parking in such an extreme, I think I'd look for shade, or rig a loose tent from a cheap tarp, and so create my own shade.

The actual dry pigments that are used in paints can be mixed into epoxy resin. IF you can get them. Automakers routinely make parts from plastic with molded in color that matches the paint job on the sheet metal, so YES, it can be done. It probably isn't going to be economically feasible to do this, though. Consider a can or two of Dupli-color touch up paint from almost any auto parts store.

Pigment in the epoxy is going to create shade ( and block UV light) that will protect all the plastic UNDER the pigment. The small amount of plastic that covers the pigment, though, is totally unprotected from UV, and thus subject to damage from strong sunlight, unless you coat it with something to block the UV light. This could be acouple coats of varnish with a UV filtering agent, or a solid (opaque) coat of paint. Again, consider a can or two of automotive touch-up paint.

Now, some thoughts that go beyond your questions:

The top of a pickup may need to handle a lot of rain, but it should never have to spent time submerged like the hull of a boat. So, why bother with fiberglass and epoxy? A much cheaper and highly durable finish could be obtained by sealing the wood and then painting with (you guessed it) auto touch up colors. You could also used a couple coats of exterior polyurethane. They use polyurethane finished on hardwood floors and it is tough enough for people to walk on it for years. You can get clear, or get some with a color. Black should be no problem to find.

If you need the structural strength of the glass cloth, then consider using the less expensive polyester resin instead of epoxy. Polyester based resin has been used in the auto industry for decades. It has a fine track record and it's properties are well known. It is nowhere near as fickle about UV as epoxy, so you don't need to cover it with varnish. The boat supply store near me has a gallon of polyester resin usually for about $18 ( including the catalyst/hardener), and frequently this stuff is on sale for $13 to $14. That would be more than enough for this project(and one or two more like it) You can add pigments to polyester resin (again the problem is in finding the proper colors and mixing them to match) Or, you can paint over the fiberglass with (must I suggest it again?) automotive touchup paints.

Buying a gallon of epoxy (enough resin and hardener to amke about a gallon) will set you back anywhere from $35 to $60. Unless you have an epoxy-resin well in your back yard, what you would save by using polyester instead of epoxy could cover the cost of the lauan, the reinforcing wood underneath, and of course that auto touch up paint. It might also cover the cost of some of the fiberglass cloth.

Hope this helps

Paul G. Jacobson