Not a Boat but its Fiberglass and I need Help

Hey all. I am having trouble trying to find a specific Fiberglass forums for automotive projects. I would like input and a buddy told me to post about it here.

I have a 1973 Jeep cj6 which is essentially a 20" longer Cj5. I bought a replacement body in fiberglass to get it back on the road . I am limited to to one manufacture of fiberglass bodies for it. They aren't known for being the best made but they get the job done.

I got the tub up and onto the frame but it has a dip in the top rail on the drivers side.. This is a pretty long area ...something like 25" is dipped down. Its about 1" wide on the top of the lip.

I have attached a pic of the top rail (albeit on the passenger side and on a cj5) to show you the area in question. In stock form Its just flat on the topside. Mine is tapered to a low point and then tapers back up towards the back end of the jeep. The last pic is the actual low spot on my cj6 tub. That's the longest straight edge I had. There may be another low spot towards the end of the jeep. At the lowest spot it is maybe .250" deep. All of the other panels on the Tub are fine it's just this one top rail.

What would the fix be for this to level it out? Should I Just grind away the gel coat and build this up with layers of stranded mat? Or should I just cut a bunch of 1" wide strips of woven cloth and start layering it? I assume i will need to gel coat this afterwards before paint?

This is a Knock around Jeep and will get a cheap garage paint job but I would really like to get this side rail straightened out. It catches the eye pretty quick. I am not sure if this body was manufactured with resin or epoxy if that matters.

Any advice on how to correct this? I'd like to try and tackle it. Anyhow, Thanks for any input you guys can give me to help sort it out.

First pic of area in question on a cj5 tub.


Second pic showing how the top of my lip is tapered down. The second lip/ledge on the outside is actually pretty straight and I am not going to mess with it.

 

Your best bet is to grind off all the 'sticking out' bits with a grinder, then build it up again with a mixture of resin and fillers.
I would bet that the body is made with Polyester resin, which would stick to the old body pretty good if you roughened up the surface, but since its such a small area, I would be inclined to use Epoxy Resin instead of Polyester. Its not that much dearer, but it sticks much better.
The 'filler' in the resin could be stuff called Microballoons that look like talcum powder, but Talcum Powder or even fine dry wood dust would work as well. It will make the Resin bulky like peanut butter if you add enough. Your local Fibreglass shop will give you lots of advice.
You would just slather it on to a close fit, then sand it precisely with wet and dry paper on a straight edge. Add more if any areas are still a bit flat.
Painting it is straightforward as you would any auto body, if you sand it smooth enough.
Good luck

 

As mentioned you can simply bulk it up so it's straight, though I'd be inclined to fix it.

To fix it, make a mold of the other side, as it too is just a straight section and flip it around to use what you cast from it, on the side with the dip. If both sides are screwed up, you can (again) just bulk it up or make it right. Making it right requires a mold, which a pain in the butt for a one off.

It would be nice if a heat gun and some cussing would do, but it's probable the mold was distorted or some other flaw in the manufacturing process, caused this and the dip is a permanent feature.

The easy way is just to bulk up what you have, to make it straight. You can make a guild from some plywood or flat bar stock to help you get it straight. You also might be able to make several cuts in what you have, prop up these sections to straighten things out, then fill in the gaps when satisfied with the body line's position. This is what I'd do. I'd make some key location cuts, separating the bad spots from the body. I'd then use some square tube stock as a guide and wedge/brace or even pop rivet the cut up pieces into their appropriate positions, using the tubing as a guide to keep it straight. This might require some temporary blocks on the back, to hold it in position, while the first round of goo goes on. Once you've got everything where you want it, "tack weld" the cut up pieces in place with some resin and mat. When this dries, you can remove the temporary blocks and guide, so you can finish filling in the gaps, holes, etc.

This is standard fiberglass repair stuff and there's lots of information online about the various processes and material choices.