Hello all and Happy New Year! First post, but have been reading and learning for quite some time now.

I have a 1969 Mustang that I re-skinned a door and in one spot the panel flexes more than I am comfortable with, is there a suggestion to reinforce an area of a door panel? I thought about panel bonding a panel to that area but wasn't sure if that is really a smart or correct way to do this. I really do not want to spring for an entire door if I don't have to. Any help would be appreciated.

Tough call to make. Personally I think you are opening a can of worms if you try to solve a loose or flexing door skin by adding more elements to it.

Can you reopen the skin and try to tighten it up?

Thanks for the reply, I am not exactly sure how to do that but it is already welded & bonded. I might wait for a decent sale on a door and/or search craigslist etc. The flexing is in the mid to lower area which I do not think will be touched all that often, I am concerned mainly with it flexing and cracking the paint etc. Do you think with a couple of coats of epoxy primer, sanding primer and the BC/CC it might tighten up some? May just get another skin and try again LOL.

Original skins move in and out some they are not all tight or stiff over the frame, depends on the shape of the panel some are stiffer than others a little flexing is normal when pushed on. Being an after market skin your gonna have to shrink or stretch to tighten it knowing wear to do witch is hard to read on bigger panels get it wrong and you risk opening up a whole new can of worms like a an oil canning situation.
An Oil Can effect would be bad.

I would go to your local autobody supplier and ask for some sound deadening sheets.They come in a 12x12 sheet or larger or smaller depending on application.Trim down one of these sheets larger than your problem area and apply it to the backside of the skin.This will cut down on flex and add a bit of strength to the area.If you have to do bodywork over the area then you will have to look at other options like something was missed when you installed the skin.HTH

Thank you all! I ended up tapping with a hammer and dolly around the edges a little more and put a heavy bead of panel bond were I could reach inside. I am going to put some dynamat inside as well, but the little bit of work I did tightened it up more to my satisfaction. There is a lot smaller area now that flexes and hope the sound deadening material will improve that even more.