My trunk area has some good sized rust holes in it.  I treated the rust with Rustoleum rust treatment then fiberglassed the holes.  This is the second time I've ever worked with fiberglass so it isn't pretty, but at least I have the holes covered.  I would welcome any tips for doing it better.  I'm not really concerend with how it looks, just want to keep water and exhaust out.

Before


After

My rust holes looked almost identical. Except I just cut out the floorboards.

My rust holes looked almost identical. Except I just cut out the floorboards.

Did your tintop have rust holes?  I was thinking they were caused by the soft top leaking before I bought it, but if your tintop had the same rust there must be another cause.

I have worked with fibre-glass in boat building.  It is a grim material, with unpleasant properties, and on the whole, I would opt to weld rather than use it (and my welding is really poor).   I think that your efforts are to be commended, firstly for having attempted it, and secondly for having a reasonable result.

In order to get the elusive fat finish that you are probably looking for, I would work from below, cutting a single piece of woven-roven to size and stippling it in-place with resin (dont overdo the catalyst though.   I would then support this with a piece of ply, painted in release agent.

Once this has dried you can work from inside the car, cutting and applying 2 layers, the first should be a thicker layer of matting, cut to fill the hole, and the second a thin (gossamer) layer with a half inch overlap around the hole.   This should be stippled with resin and will give a smoother surface than the woven roven (and it's dirt cheap).   If you want a better finish, paint with a filler paint and then falt b ack and spray.

This is a much more arduous repair than just chopping out  the floor and having a friend (but not me) weld a relacement panel back in.

Cheers

Slim, thanks for the encouragement.  I'm a bit surprised to hear how much trouble fiberglass can be.  I didn't have much trouble with it.  On the other hand I'm not going for a professional look.  I plan to seal the edges better and put 1 more coat over it.

Both of my Trackers have holes in the same place, but my 4 door kick is rust free in that area. The only other suggestion I would have would be remove a few more trim screws and the one bolt that holds the bottom of the seatbelt on both sides and pull that plastic cover off of the wheel well before it becomes permanently glued in place and so you can fix any more rust that is hiding under it...

Just my 2 cents, but fiberglass is for boats and Corvettes. Always replace steel with steel. George; 

I love fiberglass, it's great. I don't use the woven mat anymore, I always use a thick stretchy felt like fabric, it will hold more resin, and the end result will be a thicker piece that is much stronger.

Just my 2 cents, but fiberglass is for boats and Corvettes.

I've always wanted a Corvette.  When I was doing the fiberglassing I told my wife that I was one step closer to my Corvette!

Seriously I don't have welding equipment or know how. But I did have $30 for fiberglass supplies and a little experience, so that is the direction I went.

Yeah, my tintop had holes in that spot, and I think my parts rig (also a tin top) was also developing them. I got both with holes/rust there already, so I have no clue as to the cause.