Fiberglass: Thin door inner shell (Hinge Area)

[Phil]

I just came across this when I was sanding the (left) inner door half for mating to the outer half.

Apparently the door has a really thin spot close to one of the hinges. I'm guessing the hinge bolts through both halves, correct?

If so, I need to find a way to get this repaired so it doesn't affect the hinge on the tool-side and also doesn't affect the fit on the bag side.

If any of you who are working on your doors, you should keep an eye out for this one. It could get ugly if it's thin and you don't notice.

Anyone have any thoughts on repairing it?

Phil

 

[aerhed]

I'd stuff the backside of that corner with a flox mix just before you epoxy the halves together. If you build up the inside, it will raise your door above the cabin top. I made upholstered aluminum covers over the inside hinges. If you do that you can glass a strip of fabric over that crack. Just don't lay glass where the hinge itself sits or you'll raise & cant the door.

 

[Bob Kuykendall]

...Anyone have any thoughts on repairing it?

Sand-thrus like this are a real problem when preparing thin composite shells for bonding. The contours stiffen the part at the corners so that it resists the pressure applied by the sandpaper better; the other areas just bend out of the way. Consequently, you remove more material from the corners, and less from other areas. Next thing ya know, daylight!

The idea of using extra flox when bonding the shells together might work. Personally, I'd be inclined to patch it on the sanded surface using a ply of 6oz cloth or a couple plies of 3oz or so. Wetted out sparingly, it will add less than 0.010" of thickness, which is probably equivalent to the amount of fiberglass that was removed during the sanding.

Thanks, Bob K.
http://www.hpaircraft.com/hp-24

 

[Phil]

Wow, you can be an assassin with 3oz cloth! When it's wetted out you can't hardly see it. And you can slink it around compound curves like a dream.

Lucky for me, I bought 5 yards of this a few months ago:
http://www.aircraftspruce.com/catalog/cmpages/120fibergl.php

I actually added several layers across the area and I don't think I built it up much at all. Definitely not enough that a single thin layer of balloons wouldn't bridge any high/low spots in the final fitting. Amazing stuff.

Once it cures in the morning I will push on it and see how well I did. But I'm impressed tonight.

Phil