I originally did this project in 2008/9 to address leaks caused by the OEM front window. In case you are not aware, virtually all of those front windows in this generation of Class C's leaked, causing most RV's that had them to now be in the junk yard. The front cab over just rotted away and most folks did not know how, or could not pay for the expensive repairs.
Luckily, I saw the problem and rebuilt the rig immediately after purchase, when it was already17 years old.
However, in a rush to finish this job, I misjudged how many coats of resin I should apply to the new plywood exterior, choosing 1 coat rather than 2 or 3.
A pin hole in the resin caused a bubble of delamination to appear 8 yrs later at the top center of the 2' x 7.5' x 1/4" fiber glassed panel I had used to cover the window hole.
So now....the rebuild.
Using a heat gun (hair dryer would work as well) I removed the strips top and bottom of Eternabond tape I had used for 2 yrs. to prohibit any more leaking and hopefully postpone this project. Heat the tape and pull. Remove the rest with a scraper and lacquer thinner and small pieces of paper towel.
Sliced the fiberglass with a razor knife and ripped off some to see how bad it was. obviously all this panel would have to be removed.
I set my circular saw at 1/4" depth and made plenty of cuts, then pried the small sections off using a few hand tools.
Cleaning up carefully all of the old caulking and all surfaces is critical.
A slightly different approach and style for this build, but framing is kind of standard.
Cut insulation material to fill the voids and caulked all edges, sealing the sections well.
Covered the framing with a new piece of 1/4" ply screwed and glued, then using fiberglass cloth 4" tape and epoxy resin(could have used polyester for speed, but I had epoxy on hand from my boat work-yrs. prior). All edges and seams were taped, then fairing compound spread over all fiberglassed areas to be worked further. (this is just like automotive body work).
I wipe on a bit of Dykem machinists dye in lacquer thinner (could have used less dye here) to mark all work. When I sand, the color is removed except for low spots. Sometimes I can sand only once to get the surface perfect, but not often. Usually it takes 2 or 3 times of adding filler, then dye and more sanding until I get a paint ready surface.
All edges-interior and exterior- were 'rounded using a router and by sanding and then several applications of fairing material. It's 'sculpting'.
A lot of tiring work, near brutal....especially since the temperatures here have been in the mid 90's and heat index over 100!
Once or twice/day and every night, we had thunderstorms, so I had to cover the work with a plastic sheet often. The weather really slowed me down.
The plywood was then covered with a layer of Filon(shown as the white material) purchased through an Amazon seller, then the filon rec'd 4 layers of fiberglass cloth epoxied over all edges. Then, covered with fairing compound until all was smooth and ready for paint.
December it was in white primer.
Paint completed in my driveway. This was difficult as painting outside....I had to pay attention to wind, rain, bugs etc. By doing it one section at a time, I was able to prep, tape and paint without any negatives. It took some time to complete the entire RV, but now she is finished and every item reinstalled on the exterior. I'm very satisfied with the results!
Any comments?