Here's a link to a site with info on DIY wooden air diffuser. It's what gave me the idea to try making my own. The procedure is a little different (more complex than mine) since it uses super glue to hold things together and once wet, you can't let the wood dry out. I just use hand tools (miter box) and Gorilla Glue which actually needs some water to set properly. I assembled my first one dry, except for wetting the area to be glued in accordance with Gorilla Glue instructions. It hasn't failed at any of the seams and is still in service, forget how many months. As mentioned in my previous post, I'm in the process of making another one now. I'll take some photos this time.
http://www.hawkfish.org/snailman/kwairstone.htm