1960 Door Fiberglass problem

[Joe M.]

The top of the door on the passenger side is broken out where the threaded stud on the back end of the door pillar inserts. I need to build up this area to create an elongate slot as original. The underside cannot be built up too thick or the short stud will not be long enough to add a couple of washers and hex nut.

I was going to clean the inside of the door skin, apply a piece of glass mat starting on the door skin, and wrap it under the broken area and over the top. Before I wrap the mat over the top, I thought it would be a good idea to mix up a small amount of resin and chopped up fiberglass to fill in the hole on top of the new glass and make it level with the top of the door.

I can get a dremel too inside the door to sand the bottom of the repair flat and reduce the thickness such that the threaded stud will extend through the slot enough to add washers and nut.

Any suggestions on how to fix this problem a different way or improve on my plan of attack?

[Russ S.]

Re: 1960 Door Fiberglass problem

You can't wrap fiberglass mat as it won't accept the bends and still lay flat. I would (and have on this application) lay mat cut to shape on one side at a time.

[Joe M.]

Re: 1960 Door Fiberglass problem

Thanks for the tip Russ. You saved me time and trouble. It appears to me that the only side to add strips is the underside because if I lay strips on the top, I will have to turn around and sand them down, if not off, to restore the original horizontal top surface of the door. I can fill the depression on the top side with resin/chopped up glass. I actually need to do the same repair to the opposite side as well. The other side of the back of the door post has an unthreaded, vertical stud and the glass is completely broken away on that side as shown on the photo.

I am still open to repair tips for this problem.

Glass mat question - I have a crack on the underside of my trunk and I am in the process of grinding down to good glass and back a couple of inches on either side of the crack. I will bevel the outer edges. Do I lay the narrow strips of glass/resin in the bottom of the ground down area? or wide strips at the bottom with narrow strips at the top?

[Richard M.]

Re: 1960 Door Fiberglass problem

Joe, Russ has the right idea......build it up flat.

This is what I would do.......
Bevel the top edges of the open oval area. Bevel as much as possible, but be careful near the outer edge. Mask the area near the outer edge. Sand the underside area clean. Apply some duct tape underneath. Make sure it sticks good. This will act like a flat tray to hold the repair even with the bottom plane. Fill in the gap up top with your mat/resin, extending into the bevels. Build it higher than the flat area for strength. You can use chopped mat or tiny strips here to get it filled. It has to be flat, no folds. This will completely fill the area. Let it cure, then sand smooth top and bottom. Drill the hole for the stud, carefully. You may need it slotted a bit as you'll likely have to adjust the door post fore or aft. Your final repair should be the same thickness as the surrounding original glass. Just don't over tighten that stud nut.

I had a similar repair on a '67 door, where the vent window is attached. As you can see I built up the back with tape to create a mold for the repair. You'll be doing the same but gravity will be on your side.

Pass door shown. Normal appearance. The bolt holds the vent window to the inner door.
P3050003.jpg

Driver's door. Poor, weak repair using epoxy. Broken away.
P3050002.jpg

Prepped for repair....
P3050008.jpg

After mat/resin built up and sanded flush. A stronger repair.
P3060007.jpg

Your second question........Is the crack in the flat area of the trunk cover, or in the reinforcing ribs around the perimeter/hinge areas?
I always use narrow strips in flat cracks and build out on top with wider pieces to cover the smaller strips and the surrounding glass.

Rich

[Russ S.]

Re: 1960 Door Fiberglass problem

If you are doing a repair in an area that will be exterior body finish painted (seen) do not use strips that have blunt edges. Instead tear pieces of mat so you have feathered mat edges. These mat patches will then blend into the outer repair edges rather than have a straight line(blunt) edge that would later show thru your paint.

[Joe M.]

Re: 1960 Door Fiberglass problem

The trunk repair is in the area where the deck lid hydraulic cylinder bracket is bolted down; one bolt in the vertical surface and two on the trunk floor. The crack is represented by the dashed line and the holes where I ground through the glass to remove the crack (I did remove the crack). The repair will involve glass/mat on the vertical surface and wrap around under the trunk floor. Once I get glass mat on the underside, I will fill in the holes on the inside of the trunk with resin and chopped up glass; then sand smooth. I don't want to build up the inside of the trunk with strips of glass mat as it might affect the way the cylinder raises the deck lid. The repair will be behind the cardboard divider. First photo shows the extent of the crack and the second shows the length and location of the crack from inside the trunk. Should I extend the patch a couple of inches on either side of the cracked area? I am creating a structural patch; definitely not a cosmetic patch.

[Richard M.]

Re: 1960 Door Fiberglass problem

Joe, Okay, I thought you were talking about the lid. Now I see.......it's the "trunk".

I would groove out/bevel the crack area itself. Open it up enough to apply chopped mat/resin in the cracks' entire length. If you get the crack filled in properly it'll be strong enough. You could lay in mat outside the area of the crack for added strength. I would extend it just a little, maybe 1/2" or so. I may not make any difference.

Below shows many similar stress cracks on the rear fascia of the '59 I repaired. I grooved out the cracks and filled with the chopped mat/resin. I also added some behind the cracks under the lip of the cracks. The finished result was stronger than original.

PB220001.jpgP1080053.jpgP1080055.jpgP6220027.JPG

[Russ S.]

Re: 1960 Door Fiberglass problem

One thing to remember is that often times surface cracks are just that -surface only not a break thru the glass. In that case you only need to groove out as deep as the crack is often times only a 1/16 inch deep or less. The way too determine if the you have ground deep enough especially for a beginner fiberglass repair person is after you have ground out that 1/16 or less, wipe it with wax and grease remover. If the crack still exists the solvent will dry slower in the crack thereby making it visible.

[Joe M.]

Re: 1960 Door Fiberglass problem

I continued to grind the crack until is was no longer visible with natural light shining through from the trunk side. At that point, the thickness of the uncracked glass was a fraction of an inch. Rich, now that I have the cracked area ground down and beveled, I will fill the cracked area with a mixture of resin and chopped up glass fibers. Since the area is under stress when the deck lid cylinder extends, I am going to overlay the cracked area with strips of resin and glass mat for added strength; about an inch on either side of the crack since that is what I have also ground down and beveled. The attached photos show the progress I made on Monday evening. I have several more short cracks to grind out next. Probably should have kept the break through areas more to a minimum, but should be able to cover the holes from the back side and fill in from the front side with resin/chopped glass.