If this thread is somewhere else please direct me to it but my search didn’t turn up this specific topic. Otherwise...

I need to re-attach a lower hinge that broke loose when the door slammed open in 20 knots of wind. There had obviously been multiple repairs over the years and now it’s time to fix it right. The pics show where the hinge was attached, the mess that the inside became over the years and the repair we did by cutting the old flange out of the inner door frame and making a doubler with a new flange. We also installed an extra piece of .025 between the outer skin and the new flange which runs aft for about 3 in.

I’ve made a new rear half of the hinge (pin piece not welded on yet) and we were going to move the 2 screw holes forward to go thru the new flange and door material so the attachment would be very strong. I’m not crazy about drilling thru the flange because the nuts on the inside may end up interfering with the closing of the door. I’m leaning toward making a doubler piece out of .0.40, maybe 3-4” sq. and riveting it to the door outside as a doubler to bolt thru with machine screws. I’ve seem a number of different repairs in this area but can’t remember specifically what they looked like.

Does anyone have pics of a repair they are happy with? I realize that if I add a doubler outside, that the new “pin tube” will have to be welded on the hinge piece with a slight adjustment for the change since the hinge will sit slightly higher. I will also have to replace the remaining 3 round head rivets with flush ones.

Could you make the doubler and hinge half one piece, eliminating the off set issues with the hinge pin? I like the idea of coming through from the backside with flush headed screws and threading into the outside doubler or nuts on the outside.

Why not do something like a dime and a dollar patch to replace the section of swiss cheese door skin?
I think the door skins are 0.032 so the hinge could be nutplated to 0.063 worth of aluminum and everything will be spread over a dozen or so rivets. Stop the dollar before the door frame flange so you don't increase thickness there (flange it to the door frame?)

Hummmm...I’m struggling with the dime/dollar analogy. My wife thinks she knows what you mean but I’m not sure. Are you saying I should cut out the Swiss cheese and replace that section with another piece the same shape and then add the larger doubler on top of that? Not sure how the dime portion gets secured.

I guess I was hoping for someone’s photo. I’m thinking if I have the .040 doubler on the outside that would be sufficient for attaching the hinge since I have the extra .025 piece between the skin and the flange. Once I get whatever put together the last thing will be to determine what my “pin tube” offset needs to be before I weld the pin to the hinge. Attached pic of new hinge and “pin tube” waiting to be welded in the correct position relative to the forward hinge.

I dont have any photos but I've always heard a flush patch with a doubler underneith called a dime and a dollar. The dime is the flush part and the dollar is the doubler after the dime and dollar coins.

I'd cut the skin back until I'm at good metal then make a patch to fit the cutout perfectly. This keeps the outside of the door skin flush.
The doubler (dollar) goes on the inside of the skin. Since the skin rivets to the door frame at the flange, you could form the doubler to bend inward so it rivets to the door frame too.

If you're painting the door, the repair could be invisible with flush rivets and a little filler.

I like the "dime and dollar" approach, but would also bed it in a good structural adhesive, such as masterbond or something that is made for aluminum. That will beef things up and spread stress loads. Good stuff. Don't be afraid to make the doubler big.

John

Bagarre...thanks so much for the drawing and the directions. That looks like a good method. One difficultly, and I know you know this from your amazing rebuild photos, is that there are some braces and door structural members in the forward corner to deal with. The access is also extremely restricted due to only one 4” hole and a couple smaller ones.

I will certainly give it some thought though. Thanks again.

hardtail...how about Pro Seal. The goop that RV fuel tanks go together with. That stuff is STRONG.

To get access, you will need to drill out a whole lot of the spot welds that hold the formed structure to the sheet skin. You need to do enough of them to be able to peel it back a bit to get your hand in there. PRC is good stuff to keep the pieces together, that or another structural adhesive like Scotchweld or Hysol. When you put the skin back down you can try double flushing the rivets in the holes you drilled to open the spot welds. You can also source a special drill, body shop types use to drill off one side of a spot weld, kind of like a mill head with a center drill. When your all done with the riveting and such, sand the skin smooth to even up the flush head rivets then fill with some kind of decent aerodynamic smoothing putty (we are not to call it bondo) use a decent one, not the stuff from Autozone, but a paint supplier. Then some high build primer, smooth sand and paint. It should be invisible after that. Having rivet bucktails on the rubber seal side is not a big deal either, patrol doors (glass) are riveted all the way around, not spot welded.

I didn't realize 180 doors were spot welded. 170 door skins are riveted on.

But yeah, you'll need to get the skin lifted in that area, enlarge the access holes or make a bucking bar from a golf club.

The dime and dollar can be riveted together on the bench before going in so at least those rivets would be easier.

With all of that work...would it be easier to just re-skin the door?

Without seeing the entire door, hard to say if and when they transitioned to spot welding on Cessna doors. Later models tend to be spot welded or even bonded. To clarify, the adhesive really firms up a riveted coin/flush patch. It also keeps moisture from wicking between the layers and doing evil corrosion things. It is just a mess riveting patches wet. Gloves help, but when they get the goo on them they start to stick to everything as well. You will need a pile of rags to keep it and you moderately clean. Replacing the entire skin is always an option, depends on your skill level. Doors are tricky, they are curved and almost need to drill the skin installed to keep their shape. Sometimes sourcing another door from a junkyard is a better option from the labor standpoint. Lots of Cessna doors fit lots of models, it is a bit of a puzzle. Kind of need to lay hands on them.

Have you also considered ditching the steel hinges in favor of the later style Aluminum ones? Much stronger and on the bottom, it extends further back.

Id just find another door... be done with it. LOL

I have considered the later style aluminum hinges. A guy here has them on his ‘59 182. They look great,
However,when I asked at the salvage yard here they said they didn’t like them much as they had seen many break at the hinge where the pin goes through. They also said they would be at least $300.

Has anyone seen an aft hinge “bolted” with 10-32 machine screws thru the door flange? Do the nuts on the inside hit the door opening?