Another door panel thread

[grannyknot]

I'm about to start working on the door panels to try and repair some age damage before re covering.

I thought perhaps some kind of a fiberglass repair kit from Amazon, any suggestions?

Thanks,

Chris

[psdenno]

Looks like a big crack to fiberglass.  I'd probably bond in a thin sheet metal or aluminum panel under the fiberglass cloth  patch for added structural strength.

Dennis

[hr369]

If it were mine, i'de  mount it on the door and get it to fit as close as possible to how its supposed to fit and then i'de glass up that big tear.  If you patch it up with it off the car, it might not fit the

door correctly because the panel will not be as flexible with fiberglass over the top of it.  Let it dry overnight and pull it off and lay 1 layer of matt over the whole door panel.  I'de get the thinnest matt

you can find too.

ultra thin fiberglass matt here

Edited March 20, 2016 by hr369

[grannyknot]

Good points, I have never FG over anything like the fiberboard that these panels are made of, should I soak them in resin first and let it soak in and cure then coat again and glass it?

[Namerow]

There are two different types of repairs required here:

For the clip hole areas, why not approach this the same way that you would with a rust repair.  That is, cut out the bad part and 'weld in' (glue) new material , cut to shape.  Although it would definitely be easy, I'm not sure that a fibreglass repair is going to give the clip the right kind of surface to 'do its thing'.  My idea would be to start with new, 1/8" masonite panel stock.  Create a hole of the correct diameter (hole saw?), then use a small file to add the 'notch'.  Now cut out the patch panel, complete with hole, and lay it over the door card so that the hole locations line up. Trace the outline onto the door card, then cut out that area.  Now bond the patch panel into the cut-out area, using a fibreglass overlay on the 'back' surface.  While I have not tried this myself (yet), I think it could work nicely.

For the big tear, I agree that an f/g cloth-and-resin overlay will probably be the way to go.  Here's an additional idea, though --

To temporarily bond the torn edges prior to applying the fibreglass, my notes include a comment from another CZCC member to the effect that a 'thin' cyanoacrylate glue used by model airplane hobbyists works well with the door card material.  He referenced a brand called, 'Great Planes PRO CA' (packaged in the usual 1-oz eyedropper-style bottle).  I'm not really sure how they manage to make this stuff thinner than plain old Crazy Glue, but it's promoted as having 'superior wicking action'.  The label on the bottle says, 'Great for tight-fitting parts, tacking and CA hinges'. The Z owner in question said that he used it successfully to firm up 'mushy fibreboard around the holes' and reported that it resulted in an area that was 'super-hard and strong'.  So:  If you can figure out a way to press your torn edges together and flat, this glue might just do the trick.  If you've got a spare piece of door card, maybe use that to experiment with first.  Alternatively, try cracking a piece of masonite sheet and the use the glue to try to re-set the crack. 

Let me know if it works .

[Patcon]

If it were me I would go fiberglass for the whole repair. I think you're right to use some resin to wet down the board first. I would use resin to make the initial repair to the crack and hold it close with screws or some weight over wax paper as a release sheet. Then back up the repair with some light weight matt. I think HR's recommendation for using the door as a jig is a great idea too. Once the initial repairs are done you can remove it and back it up from the back side if necessary. I get a magazine from Epoxy works and they do all kinds of projects with fiberglass and resin. It should do fine for all the repairs you need to make. At the holes I would thin down the board around the holes for the repair. That makes room for the repair material without too much overbuild. Whenever you patch holes in fiberglass you all ways try to make transition areas for the repair, same principle..

[charliekwin]

Fiberglass resins will bond to that stuff until the end of time, no need to soak them beforehand.  If you do glass them, you'll want to set up some kind of jig to keep the panel from going out of shape and/or shrinking during when it cures.

If it were me, though, I'd head down to Home Depot and get a half-sheet of masonite and a flush trim bit and just bang out a new one.  Fiberboards weaken over time and it's likely to tear out again.

[Captain Obvious]

How would you handle the bend near the bottom? Flat is easy, but have you bent/formed/contoured Masonite?

Sounds like you've got some experience working with the stuff? Soak it and dry it in a press? Maybe a little heat?

[sweatybetty]

im curious also. whats a flush trim bit? my panels are junk, and ive been trying to figure a way to make new ones

[Captain Obvious]

I believe the flush trim bit is the cutting tool you put in your woodworking router to shape edges on stuff.

As in: "Rough cut to shape with a saw and then use a flush trim bit in a router to cut the edges to final shape."

[charliekwin]

Yes, it's a router bit that's a straight cutting bit with a bearing are the bottom (or top) that rides against a template piece to produce an (almost) perfect copy.

As for the curve, I haven't pulled my door cards yet, so I'm judging just by outside appearances here, but the Masonite may be flexible enough to bend and stay there with the door clips alone. If not, a couple of relief kerfs and a little resin would do the job.

[Captain Obvious]

Maybe I'm underestimating the flexibility of the stuff, but I give it about zero chance of success trying to use just the door panel clips to retain that shape. And I'm not sure relief kerfs would do it either. The word "snap" comes to mind. Followed by the word "$^!#!".