The Ultimate DIY thread - Ubuilding (Pics)

and yet NASA is using metric system,go figure.

Yup...NASA, the military, medicine, engineering....
I started grade one in '77 and that was the year of the official change here. It was great because I grew up learning metric in school but everyone around me was still using Imperial. Most folks around my age that I meet are 'bilingual' that way.

As far as the finishing (called fairing) goes, you normally mix up your fillers and adhesives using your laminating resin as the base. If you mix one additive, you wind up with a glue. Another gives you a lightweight, easily sanded filler with a texture and hardness similar to drywall mud. There are other additives (low friction, high heat, non skid, pigment, etc) but those two are the most used. That ensures that there are no compatibility issues between products.

It is a lot of work at first but once you learn the process you begin to develop tricks and techniques that cut down on your fairing time. My panels are all flat, so as long as I maintain their flatness and their alignment to each other (hence the temporary formers inside), fairing should be minimal.

One thing is to squeegee out as much resin as possible - after it hardens, dragging a dry squeegee across it should sound like a zipper.
Then one needs only a very thin skim of filler to fill the weave in the cloth and a light followup with a sanding board. The filler is normally made by mixing thickeners to the same resin used for the layup. That way, there are no compatibility issues. The filler has a texture like drywall mud and sands really easily, especially when you use only enough to fill the weave. Just like anything else, one could get it glass-smooth...it just takes time.

I'm likely going to use an industrial (epoxy) floor paint inside and out. The one I've used before (Interlux) goes on pretty thick but not so much that it'll be a problem on the sides. I'll probably do a few thin coats on the sides if the self-leveling nature of the stuff will hide the roller tracks - it does on the floor and gives you a nice smooth finish since it takes a few hours to gel.

I think thin coats will be the key...but I won't know for sure till I try it !
If not, there are a lot of paints that are compatible with epoxy - latex house paints being the cheapest and simplest to use. Let the epoxy cure, wash down with a ScotchBrite pad and lots of water to remove the blush (waxy byproduct of curing in humidity), prime and paint.

One great site to poke around is the West System website. They are the best known resin formulator, have been at it for years, and have devised all sorts of ways to test their products. Most interestingly, they publish the results: even the failures !
Here's a page on priming over epoxy. Their user manual is a good start for anyone wanting to play with the stuff - there are some things I do differently, but it all works...especially for a beginner.