3/4" is preferable, but if all you can find is 1/2, you can always double it up. Also, 5/8ths inch MDF would be acceptable for such a small enclosure, no bracing is needed either. Best tips I can give you to box building :
1. Make sure all your cuts are square and spot on, don't trust the guys at home depot to give you perfect cuts. If you use them, make sure you give them dimensions that are about 1/4 inch too big, because more often than not, they find a way to **** up, so have them cut big, and then finish cut at home to exact specs.
2. Use Titebond or Titebond III glue to hold the box together. NOT screws. Screws are there to keep the box's shape while the glue cures and keep a constant pressure. Yes the screws add strength, but they should NOT be what holds your box together.
3. I guess this is a continuation of part 2. If you're going to use silicone anywhere on your box, it goes into the corners once the box is built, NOT in between two pieces before they go together to fill in huge gaps or hold the box together.
4. Lastly and probably the most important, invest a bit of money or borrow some wood clamps and 90 degree braces. No matter how exact your cuts are, if a wall on the box is put up and it's sloping a tad, it'll throw every other measurement and piece alignment off and you'll have to start over.
Hope that's not too much of what NOT to do lol //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
Good luck with the build //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif