944S damaged door panel repair

The door panels on many pre-plastic-everything era cars are made from what looks like beefed-up egg carton material. The door panels on the 944 fit this description, and unfortunately for us of the Porsche Enthusiast persuasion, this type of door panel material doesn't hold up well under the onslaught of moisture, multiple remove-and- re-install cycles, and car stereo installation weenies.

 

I had promised that the next post would pick up from where the last one left off, but today I was working on one of the door panels and it turned out to be such a quick, simple and strong repair I thought I would share it now, rather than later - icb.

Background

The door panels on 34 year-old Gretchen had a couple of soft, floppy, mushy sections. It was mainly water damage, but also one of the plastic retainers had been ripped out at some point in the past, and was hanging on by a bit of padding that had stuck to it. I had taken the driver's door panel off to replace the broken central locking lever. That fix went great, but I couldn't just put the door panel back on without at least trying to shore up the damage - classic A leads to B leads to C.

I searched and searched, but couldn't find any information on the internet detailing how you could repair this material without replacing it outright. I am planning to replace these panels when I find a good set, but for now I just want these to hold up. I was pretty surprised to find nothing at all online; I can't possibly be the only one who has this problem. And they couldn't be very hard to repair, the stuff is almost like paper mache. As it turned out, these things are not at all difficult to repair.

Here's what I came up with

I had an idea that wood glue and some kind of a similar backing material would be all that I needed, applied sort of like a fibreglass repair, only less messy. This turned out to be pretty accurate. I'm sorry that there are no "before" pictures. I was making this up as I went along, and I only decided that the info could be useful to share afterwards. 

Materials:

• Tite-Bond III carpenter's glue - Any weatherproof exterior grade wood glue should work. 
• Poster Board (Also called Bristol Board in some places), not glossy, about as thick as a business card.
• waxed paper

Tools:

• 1" paint brush (I used a chip brush from Harbor Freight, worth about $1.00) 
• Sharp scissors
• pencil
• small clean stainless steel or brass brush (Toothbrush-sized)
• A couple of 10 Lb weight lifting plates
• a few wood blocks, whatever matches the repair area. Some should be 1.5 - 2" thick to support under the door card
• a 1" rubber roller (i.e. a veneering roller) is optional

Here's what I did

1. Remove the door panel, clean it, and lay it on a table or clean workbench
2. Remove the arm rest (I also had to remove the tweeter that had been installed in my door).
3. Support the edges of the door card with a few wood blocks so the arm rest area is not stressed.
4. Roughen any smooth sections in the repair areas. In my case, these were black-painted areas near the bottom of the door card; I just needed to open the surface up a bit for the glue to be able to soak in. I used the stainless brush for this.
5. Cut out repair patches from the poster board. I went beyond the damage by an inch or two wherever possible, but I stayed clear of the leather that wraps around the edges of the panel and is stapled in place. There is no need to cover that. The glue won't stick well, and the staples will corrode and weaken the repair area.
6. Apply the glue liberally and spread it out with the brush. it's OK to go beyond the repair area. Again, stay off the leather. If you do happen to get any glue on it, it's not a big deal, just dampen a clean cloth and wipe the glue off before it can dry.
7. Press the repair patch on. For the small area, I pressed it on and held it down by hand, smoothing it with the roller and pressing it until the glue set up - about 5-10 minutes. For the large area, I did it in two steps - first I put glue down on 3/4 of the area (the left side), then put a 2x10 under the repair area of door panel, followed by the repair patch, then a layer of waxed paper which prevented the next 2 x 10 placed on top from sticking, followed by 30 lbs of weight. I left this to set up for three hours. Then after the glue set up I glued the right section that curves around the hump of the door pocket area by hand, holding and smoothing it and using the roller as well until the glue had set.

Once the repair dries, you will be surprised at how stiff and solid some thin card stock and glue will make the door panel. 

2x10's are used to support the door card from underneath. This reduces the stress on the armrest area.

 

My car never sees any water, whether from a car wash (I use Wash Wax All to clean it) or a rain shower, and it never sees snow or salt. If you do this repair and your car is driven in harsh weather, it may not hold up very long. 

I plan to spray or brush on some kind of water proofing after the glue has completely dried. This will either be more glue, thinned with a little water, or maybe Thompson's Water Seal (sprayed on). And of course I'll be replacing the vapor barrier before installing the door panel.

 

I pressed this patch into the glue by hand; it set up in about 10 minutes. I also put a 2x10 under this area for support so the door card would stay flat

I stayed away from the edges where the leather wraps around the door card

This area took 10-15 minutes of pressing and smoothing, but then the glue set up and is very stiff now, like the way it was originally. Cuts were made into the poster board patch to allow it to follow the curvature of the door pocket. The green foam on the left was glued down in its original position on top of the patch afterwards.

  A good deal of the inspiration for this repair technique comes from watching Chechaflo videos on Youtube. If you haven't seen his work, you really owe it to yourself to take a look!

Next time, we'll get back to the work that was done to put this car on the road. Thanks for visiting!