I've made some more progress. the epoxy skin has made me really appreciate epoxy in general. I mean that in more ways than one. it is a GREAT product for specific things. skinning gets a much thicker/stronger coat than urethane, laminating panels together with glass is an amazing way to get a water tight seal. and laminating/ glueing two products together with epoxy allows for joining on a less than perfect plane, something that wood glue does not allow.
I also respect Epoxy as far as its working time and breakdown of materials go. my foam roller would last me right at 30 minutes. if I tired to go longer than that I ended up with specks of foam in my finish... something that required me to take a razer to the shave off, then sand smooth. it also has a viscosity that gives it a life of its own. it will stick to ANYTHING and then find a way to dribble off. all in all, I am glad I spent the money on it. I have 2 coats on the entire trailer (including the bottom), with a third on each side and I still have about a quarter of my 1.5 gallons remaining. If I ever do something likes this again, I will use Epoxy to bond foam to wood rather than the 3M Fastbond. the cost is the same and epoxy gives a better product.
to the pictures!
the galley is all cut flush with wood trim covering the foam. I used 3mm BB ply for that, cut to size and will epoxy over it all. yes there is a slight dip on the main hatch cross spar. I didn't notice it until it was too late. I have not checked to see if this will affect the function of the hurricange hinge. I hope it doesn't but if it does then I will shim/fill in the middle to bring to top back to flat.
another shot from inside the galley on the end cap. it was glued with gorilla glue (to foam) and wood glue to the 3mm ply of the wall. I clamped it where I could and used drywall screws into foam to provide some clamping force while the GG dried.
profile shot of the rear and side together.
after 1 coat of Epoxy. I used Raka UV inhibited slow cure. it has a pot life of 30 min at 77* and was very forgiving to me as a novice. the wet out was quite good on the fiberglass taped seams and it dried crystal clear and colorless.
I cut my own tape from a 1 yrd square of 2oz cloth. I wish I would have paid the extra $15 for a roll from raka. it would have been easier than cutting my own. and the same price as I had to buy 2x 1 yard squares to get everything covered. having said all that, I learned a lot about fiberglass. cut on the bias, a 45* angle, causing the weave to make an XXXXX pattern. that way there is no loose threads at the ends of the piece that fall out of the weave and end up as globs of thread in your project. also I imagin it is stronger because at a 45* angle, you have twice as many threads crossing your joint opposed to only weft of the weave crossing while the other directing in parallel to the joint. and XXX is stronger than an HHH when joining.
two coats of epoxy,
oh no! I ruined my trailer!!! joking...
oh wow that really stops the heart the first time to sand to get to the finish you want. I first washed the amine off, RAKA UV is supposed to be a no blush, and I did it under warm and dry conditions, but I washed anyways out of an abundance of caution. then I sanded with 150 grit. the real goal was to knock down the drips, runs, and tape seams, and then fast pass over the whole surface to provide a good mechanical bond. I oversanded in two spots and had to reapply some stain, left it on for 10 min and wiped off the little bit that hadn't dried. after a coat of epoxy I couldn't tell where I oversanded.
I plan on one more coat of epoxy on the sides and seams and leaving it at that. the roof will be covered in aluminum, and as of now, the sides will be left bare. the wood looks better when wetted out with the epoxy and I don't want to add another 100lbs of aluminum. I may paint at some point in the future, but the epoxy is good enough to get me out the door before camping season ends.
as far as the finish. I just don't have the patience to do a proper job. the tape at the edges is noticeable up close, but it passes the 10ft test after the single pass with the 150. plus half of it will be hidden by the trim. the field looks good and I think I will be happy enough with it. I hope to be campable for labor day so I will go naked epoxy through then. after that I will either paint or put on several coats of spar urethane.