What is 525 Aluminum?

I'm not specifically familiar, however if I had to take a guess, I'd say possibly some old aircraft material spec? try www.matweb.com for today's material database. IF you could say what the part will be used for and subject to, maybe someone could recommend a suitable replacement material.

Thanks for the reply. It looks like you made a good guess. The material is actually 52S (not 525) - someone else looked at the drawing and pointed out my error. A search for that number brought me to an old Aircraft Mechanics Handbook.

The part is actually used as a front panel for a rack mounted matching transformer, which is used in conjunction with other rack mounted electronic test equipment. There are some binding posts and and switches protruding through the front. It will have a clear iridite finish, then painted on one side.

Check out the table at http://www.tpub.com/content/aviationmaintandmisc/TM-1-1500-204-23-6/css/TM-1-1500-204-23-6_114.htm. The table shows conversion from old alcoa alloy designations to current designations.

Are you sure it is not 5250?

that is a fairly common alloy, for aluminum filler at least.