Woman Interrupted asked about the backing situation to this here corkboard:
Here the best explanation I can manage seeing as it's already put together and I definitely won't be taking it apart. Here is the top view of the frame I used - it happens to have a thick border. First layer is the plywood, second layer is the beefy part of the frame, an the last part is the actual decorative frame molding you see from the front. Then there's my fuchsia knit slippers with a little pom-pom which have nothing to do with this post. Anyway.
At first, the Husband attempted to attach the plywood to the inner ridge of the frame (where glass would normally sit) because he kept talking about "you'll be able to see the gap in the frame if we attach the plywood to the outer perimeter." That that didn't work out all that well. I explained that the corks will cover the gap, so go ahead and measure the bigger perimeter - not where the glass and picture normally sit.
He measured and made the cuts. I'm not sure what saw he used. You could use a hand saw but that there'd be a pain in the 'ol rump. Power tools make everything easier. A jig saw is a good all-around saw for small cutting jobs (they sell them at Lowes - cheapest one for like $30 - we have used the crap out of ours and we bought one of the cheaper ones back in 2003). You can even use a table saw which gives the straightest cuts but not everyone has one of those (we do, because I insist on doing things ourselves and the Husband likes power saws for whatever reason. I guess because he's a dude). The plywood you can get at Lowes or HD - they sell smaller pieces, like 4'x4' and 2'x4' so you don't have to figure out how you're going to lug an 8-foot sheet home with you. Unless you have a big pickup then the 8-foot sheet is the most economical. You might even be able to finagle an HD/Lowes associate to cut the plywood down to size for you - I think they do up to 2 or 3 cuts for free. But then if it's wrong you gotta go back (good reason to figure out how to do it yourself). For the plywood thickness, 1/4" to 1/2" is a good range. Here is the back where it's screwed in with 3/4" screws that we had left over from the master closet organizer installation.
Let's say you have a frame like this here Cheap-O IKEA one (that's one of my watercolor paintings. Back when I had an apartment and copious amounts of free time).
With the backing and picture pulled out you can see where the glass sits there's a little ledge in there.
That's not where I'd attach the backing if you're doing a cork board. Measure wider than inner frame. As long as you don't go all the way up to the outer edge of the frame, the plywood won't be visible when you hang it up. You need enough overlap on the thick frame part to be able to screw it down. The appropriate screw size will depend on (1) your frame thickness, (2) your plywood thickness. It's kind of important to get the right length screw so that you don't screw all the way through to the other side of your frame, but you have enough to grab onto some of the wood framing. You may have to remove any hanging hardware from the frame if it's in the way of where you need to screw - usually that's pretty easy. Then you just have to reattach it or buy some new picture frame hanging hardware also sold at Walmart, HD, Lowes, etc.
All in all, this corkboard cost maybe $8. I already had the plywood lying around from the kitchen remodel. The frame was $5. I used about 10 glue sticks that I already had. I did buy a high temp glue gun for $5 (I only had a low temp one). Even if I include that it's like $13. The key is getting a decent frame on the cheap.