I figured out how to fix delamination without removing exterior panels. This will make any delam better and perhaps like new, unless the delam is serious. On older RV's with rippled filon sides, it will probably look like new. On newer RV's with flat shiny fiberglas it will probably won't look entirely flat, but it will sure look a lot better. If your RV has composite plastic exterior, it might not work as well. I tried doing this on an older Toyota with some sort of composite reinforced plastic siding -- it did look better but the doggone composite would not compress back fully into place.
What you need:
1. Quarts of slow-set epoxy See: http://www.systemthree.com/store/pc/SilverTip-Epoxy-c10.htm
2. Large-body syringes with smaller tip (drug store). Veterinarians have larger ones if the drug store does not.
3. Length of 1/4" OD vinyl tube (hardware store)
4. Plastic ribbed tees to connect tubing with.
5. Old glass jars, small to medium size
6. Hunks of 1/2" plywood of suitable size to cover the delam area(s)
7. Fat bubble pak (office supply store)
8. Staple gun
9. Popsicle sticks (craft store) or other small stirrer
10. Old vinyl reinforced tarp or plastic dropcloth you don't mind wasting
11. 2x4's in assorted lengths
12. Bungee cords, nice selection, fairly strong ones.
13. Several clean paint stirrer sticks
14. Throwaway rubber gloves
15. Lacquer thinner.
16. Paint thinner
17. Cardboard box cut up into about 18x24 pieces
18. Ductape, don't use the kind that gets really gummy in the heat and leaves a mess.
19. Old clothes and old shoes you don't care about
20. Coathangers -- the 1-piece wire metal style with thicker wire
21. Full roll of paper towels
22. A helper over the age of 12 who has strong arms.
1. park the RV someplace where you can lean the 2x4's against the delaminated area and wedge them into firm ground or pavement while leaning against the RV.
2. Remove something to get access to behind the delam area. The wainscotting strip or perhaps or roof strip can come off. You might have to take a window out if there is no other way to get access to behind the delam area.
3. tape dropcloth sections below the gluing area and lay some under the RV so you don't end up with epoxy running down any exposed sides of your lovely RV or onto your lovely driveway. Put weights on the dropcloth under the RV so it doesn't blow away or flip up.
4. Cut plywood to size if needed. Staple bubble pak on one side of the plywood. If the plywood is warped at all, put the bubble pack on the inside curve side.
5. Cut 2x4's if needed for proper length. I screw shorter pieces together with deck screws to get the desired length.
6. Drill the plastic tees out so they have a larger inside diameter (so epoxy can flow thru them better)
7. Assemble your glue shooter: Cut the tube long enough to get all the way into the delam area. Push it on a syringe and put a tee on the other end. Cut a coat hanger long enough to tape to the syringe and still support the tube all the way to the tee.
8. Temperature should be about 60-80 degrees, but not under 50 or over 95 (epoxy sets too fast when it is hot and won't set when it is cold). Don't try this if it looks like it will rain.
9. If you have a large area that is delaminated, only do about 3'-4' at a time measured horizontally. You can't do the gluing operation fast enough to do a larger area.
REHEARSAL BEFORE GLUING:
1. Have your helper hold the plywood against the side of the RV with the bubble pak facing the RV, while you get a couple of 2x4's wedged into place. The 2x4's should be at a fairly steep angle, about 30-35 degrees arc off the side of the RV. Use bungee cords around the 2x4 and hook them to the underside of the RV to form a clamp. The tip of the 2x4 will push the plywood up against the side of the RV nicely.
2. You need to have an end of a 2x4 at about every 12"-15" of the plywood going both vertically and horizontally in a matrix. Your first time around you need to get all the bungee cords in place so you know you have enough bungee cords. In most cases it will take 3 sets of bungee cords per 2x4 to get it nice and tight. You know it is tight when you push hard on the plywood and it does not move in.
2. Take it all apart, laying the 2x4 in order so you can put them back in the same places later. Lay your bungee cords out so they are lined up and not hooked together in a mess.
3. Ductape 2 glass jars in the center of a piece of cardboard so it does not move around. One of them gets filled part way with lacquer thinner, the other will be filled with as much epoxy as you need.
1. NO SMOKING OR FIRE ANYWHERE NEAR YOUR WORK AREA
2. Put your gloves on, mix the epoxy. Measure the hardener carefully. I suggest using about 10% less hardener than suggested so the epoxy does not set quickly (when epoxy it in a jar it gets hot and sets up quickly). You can put the epoxy in the fridge to cool if off if you are worried about it setting too fast.
3. Mix epoxy quickly and THOROUGLY. From this point on, you are working against the clock so do not waste time.
4. Dip the tee end of your glue shooter into the epoxy and suck the thing full of epoxy.
5. Insert the tee into the delaminated area at the HIGHEST point and start shooting epoxy, moving the tee back and forth to distribute the epoxy. You need to do this fairly quickly. When you pull the glue shooter out to refill, your helper pushes on the side of the RV to flatten the glue out so it doesn't just run down inside the cavity. If there is de-laminated plywood in there, squirt both sides of the plywood.
6. When you are refilling your glue shooter, your helper's job is to press hard several times in the area you just shot glue into to spread the glue around so it doesn't all run out. Your helper keeps track of where you have already shot glue (using little pieces of tape stuck on the side), and then lifts the panel away from the side of the RV with paint stirrers so you can slide the glue shooter back in easily for the next squirt.
7. For some areas you might find it easier to dip a yardstick or paint stirrer into the epoxy and work it into the area. I takes several tries with this approach to get enough in there.
8. Keep shooting glue in there until you start to see it running out at the bottom (if you are working in an area where that can happen) WARNING: If there are hinges or locks under where you are shooting, be careful because the glue might come out at the hinge or into a lock). If that might happen it is best to remove these items before shooting.
9. Rip your rubber gloves off. You do not want to get epoxy all over the RV. Clean your hands off with lacquer thinner if you got any on your hands. Get the plywood sheet into position with a couple of 2x4's and bungee cords so the plywood stays in place. Put the rest of the 2x4 in place with all the bungee cords. Press on the plywood in various areas to make sure it is all snug against the side of the RV.
10. Clean out the syringe by dipping the tee into the lacquer thinner all the way up into the syringe body, and shooting it out again. Do this several times.
11. If you got epoxy on anything your should not have, clean it off with paper towels and lacquer thinner. The usual precautions about your RV paint and plastics apply. You can use paint thinner instead but it takes more rubbing to get it all off.
12. Take the syringe plunger out of the syringe and wipe it clean with lacquer thinner. Leave it out of the syringe.
13. Let it set for at least 24 hours. Save the glass jar you mixed the epoxy in so you can check it to see if that epoxy set. If it is still sticky, do not take the clamping arrangement off until the epoxy in the cup is nice and hard.
By now, your neighbors probably think you have lost your marbles. Who cares, go have a beer.
If you need to do another section, you might want to replace the plastic tee and tubing. If they did not get fully cleaned out it will be much slower shooting glue the second time.