Originally Posted by
BobF
Tripton,
1/2" birch ply will work for a skin, but you may want to use 1/4". I say that because you probably don't want to use the ply as a spoil board. You will need to add a layer of MDF to act as spoil board. If you have a traditional lumber yard, or a sign shop or cabinet shop in the area, they may have some. They can probably tell you who in the area has quality material. If they order theirs from a distant yard, they may add a sheet or 2 to the next order for you.
You want something you can surface with the machine to make sure it is level with the machines travel. I used 3/4" MDF because that is what I had. Useing thicker material means I either loose a little Z travel, or have to surface it down to original dimension.