Hi there, what would be the best ways to tackle the following two repairs on my 1977 C3.
Reading up on here, it seems it would be better to use epoxy rather than polyester resin, but would it be best to use glass fibre sheet on the door or just build up with epoxy.

JB weld do a epoxy based plastic weld epoxy putty, has anyone one here used this before?

Any advice would be appreciated as I've never done anything like this before.

 

With a 77, do NOT use polyester resin. Epoxy or SMC specific resins are needed.

The door damage needs fiberglass to provide the needed strength for the repair. The smaller damage on the body can be addressed with a quality filler.

For the door, you’ll need to remove the paint (locally) on both sides, then sand the damage to a feather edge with at least a 1” transition from the edge of undamaged material. Tape a piece of cardboard, covered with aluminum foil, to the outside of the door to act as a mold, then layup the fiberglass in successive layers, each wider than the previous layer to encompass the aft edge of the door by ~ 3/8”. Once cured, rough sand to contour. You may have to apply a second layup after the rough sand if the surface isn’t to the desired contour.

 

Do you have the missing piece? If so something like 3m 8115 panel bond or equivalent epoxy to bond part to the door, if not then you will need to make what you need. As already stated by 69L88 the proper materials for smc repairs are needed.

There are other options of replacing either the outer door skin panel or finding a used door. Me personally would opt for either used door or outer panel replacement because the drivers door gets used more often and prone to possible failure.

 

Thanks for the replies.

69L88, thats just the sort of advice I was looking for, thanks. Like I said, I've never done this before so we'll see how it comes out.

Mr E, no I don't have the missing piece sadly, I bought the car with the damage, it's been sat for 25 years, a solid car, but very neglected. I do have a spare door that came with the car, he was going to take the skin off but never got round to it. The car in never gong to be a show car with stunning paint work, I bought it just so I can learn how to fix up a C3, so far I've rebuilt most of the back end, rebuild calipers, made brake lines, installed new rotors and checked the run out, , new shocks, refurbished the half shafts, quite a lot really, today I've swapped the alternator (that's another thread), installed a new horn, and am nearly finished refurbishing a set of alloy wheels for it. The car basically needs everything doing to it. But at this moment, it drives safe enough and doesn't go too bad, but there is still lots to do.

Going forward I've got a LS1 engine apparently making 580hp and a T56 magnum transmission, so I guess I need to learn how to fix this car as stuffs going to get broken. How much breaks will be depending on how big my ***** are.

I've given the area a good sanding down and have ordered a epoxy repair kit which will come in a few days. Any thoughts on it so far?

 

I say you have jumped in with booth feet and not afraid to get wet...nice! I plan on doing an upcoming thread covering the things that can be accomplished in a home garage with some thought, patience and vison.
Not every car needs to be a 100k resto to be fun and having satisfaction of doing it yourself. Sounds like you off to a really good start.

 

Unlike sheetmetal repairs, fiberglass is far more forgiving and if you grind off too much, you can always lay up some more glass and resin and try again. You can also plan and execute the repair in stages. I’ve done a lot of patchwork by laying up one side, then letting cure before applying layers to the opposite side.

Each repair is unique so don’t overthink too much. Precutting and trial fitting your fiberglass mat and having them lines up beforehand makes everything easier.

Be sure to thoroughly clean the areas with a high quality naphtha product. Not sure what you have in England but I have no doubt some good stuff is available.

 

Ok I had a go this evening, not sure how it will come out yet but I don't think I'm too far off.

On the outside (to keep the lines of the door) I made backing strip out of cardboard with foil glued to one side, and before held it in place I cut a piece of matt the same size as the repair area. I applied this piece first then slid in smaller pieces in to the gap with plenty of epoxy, every piece was smaller.

Then once I'd built up the outside of the door, I cut some strips about an inch wide and put these over the thin steel that was exposed on the inside, the theory being it will be a stronger repair if there's a decent amount of matt on both sides.

I just need to let it cure now for a day or so and see what it looks like when I take the cardboard off.

 

Outstanding!

 

Looks great!

The fiberglass provides the strength to the repair.
Make sure it is similar in thickness to the original.
It doesn't have to be perfectly smooth, just strong.
Then the VPA glass reinforced filler can make it smoother.
Body filler is the last step for glass like smoothness.

 

Be sure to wear a respirator when sanding/grinding the fiberglass.

 

By today it was certainly cured to the touch and seemed solid so I took the backing cardboard off and it's come out pretty good, if I say so myself.

I then got a bit of card and used the crease in the passenger door parallel to the door handle as a datum of sorts and traced the edge of the passenger side door, cut this out and then flipped it over to get the mirror for the drivers side.

Using this I marked out a line on the repair and used this as approximate place to cut, leaving a bit extra on all way round.

Trimmed off the excess with a dremmel, with glasses, gloves and a respirator for safety and I've now got the approximate shape back.

I'm going to leave it all to cure for a few more days to make sure it's 100% gone off before I start to sand it back.

I'm pretty pleased with how it's going so far though.

 

Looking good.

Like playing with mud when you were kid.
Just shape it and shape it again!

This lip concerns me tho.
I would suggest to check and/or repair your door hinges before you do any more door to fender fitting. Are they loose?

 

Leigh is spot on! Relatively easy job to replace the pins and the bushings.

 

If you look at the first post, you can see the door fits up pretty well. In the recent picture the door isn't closed properly and its a perspective trick that makes it look like there is a problem with the hinge.

BTW I do have another C3 with a sagging door but that's a problem for another day.

After a bit of sanding on the edge and the fit up is pretty good. The only bit that needs a bit more work is the top corner which is a bit too rounded for my liking, but other than that I'm happy with the results so far.

 

I looked at your first picture again and agree with your assessment regarding door fit.

To address the corner, follow your original procedures and lay up a bit more fiberglass, wrapping over the corner to ensure you have glass fibers in the repair area. Resist any temptation to just build up with any fillers. The key to strength is the presence of the glass fibers.

You are doing amazing work for first-timer!

 

That's is an amazing improvement vs what you started with!
Nice fiberglass skills.

I would check to see if a small adjustment at the door hinges can fix most of that remaining vertical gap.
It looks much better now that the door is fully closed, but still looks 1/16 to an 1/8" low to me.

The latching of the door itself should not drag the door back upward into alignment.

It should already be aligned, before clicking it latched, and then just require slight pressure to click it, with no vertical movement at all.
Once the hinges wear, it requires a slam.