People wil want more info.

Is the 500 x 500 the size of the sheet, size of the angle or contact area that you have.

Any load involved or just cosmetic. temperatures, chemicals, etc.

We glued the VC10 aeroplanes together with araldite – seemed to work OK ! Just follow the instructions on the packet.

Bob

What I heard in the Interwebby was to put some epoxy on the part and sand through it. It would keep the aluminum layer from oxidizing. Sounds messy but might work.

Permabond is a brand not a type of adhesive.

Lumiweld, or similar? Permanently bonded at normal temperatures.🙂

When I was involved with the design of railway carriage doors, the makers of the things used Redux 609 adhesive, which is an epoxy with a cotton scrim. It comes in easily-cut sheets, so you cut the size and shape you want (scissors), clamp it between two sheets of aluminium and apply some heat. I’ve just enquired on the Interweb Thingy and it’s still apparently available. If you’re only after one piece, perhaps a request for a sample?

The rubber tyres on my Clayton steam wagon were stuck on with the stuff; I think 100 Celsius sort of temperature was required and simply I popped them into the domestic oven.