I wouldn't expect there were any blanks available, simply because there wouldn't have been much market for them, and also because that metal is a f**king pain in the ass to cut without a stamping machine or whatnot.

Most ATX boards used one of a few common layouts, though, so it shouldn't be too hard to turn up a suitable one. Assuming it's not a particularly ancient board, you can usually even contact the motherboard manufacturer and they'll send you a new one for a few bucks.

I seriously doubt these are made from mu-metal...

Ok, fine. My point was that there's a reason blank plates aren't available, I really don't care about the semantics of what the material is called. It's some sort of special metal for shielding, which is a pain in the ass to work with... if it's not mu-metal, it's something along the same general lines.

That's nothing special, wouldn't make sense anyway because the case is made from "normal metal" too.

The manufactuers just want us to buy new motherboards instead of new backplates 😜

That's nothing special, wouldn't make sense anyway because the case is made from "normal metal" too.

Well it's certainly not standard steel sheetmetal. It could be some sort of spring steel or something, although I've never seen rust on one, so there's probably more to it than that. Either way, though, it really doesn't matter for the point at hand. I don't know what it is, and I don't care... I still call it mu-metal since it's for RF shielding, in the same way that tissues are 'kleenexes' and soda is "coke".

Mu-metal is especially for low freqencies, no use with RF 😉

*sigh*

This really shouldn't have been a discussion in the first place, nor did I want it to be, since it's completely inconsequential to finding an ATX backplate. So... there... I have edited the "mu" out of my original post. Let's get back to the topic at hand, shall we?

I once got a LX-format Socket 7 motherboard. I never had the LX style IO backplate. I cut out a piece cardboard from an old mobo box to cover the back panel opening. I made a small rectangle opening, just enough to expose the mouse and keyboard ps/2 connectors. (Which are side by side in LX format.) Fixed to the casing with the help of cellophane tape.

It won't look good. But then again, it's on the rear of the casing.