The reason behind this drawing board is that while drawing on the ipad while on a table top or handheld your palm is not naturally resting on the same plane or level surface as the screen. Imagine drawing on a piece of paper, your hand is in the same plane as the paper. So I wanted to perfect this environment.
I purchased a sheet of 16"x24" of near-white acrylic "plexiglass".
I then measured the panel into two equal parts and drew a line. I will cut this in half and use one half as the bottom. On the other half I traced the size of my iPad. It's best to leave the protective film on the panel until your cutting is done to prevent unnecessary scratches.
Next I use a grinder to cut the panel in half and cut out the rectangle ipad area. Be sure to your ear and eye protection. I also used a table clamp to keep the panel secured still while cutting. It does take a steady hand to cut straight.
Next I used a dremel power tool to router the ipad area with a bevelled or curved bit so that the ipad is cradled perfectly. I was sure to cut away less than necessary and check the fitting of my ipad. I did this several times as not to cut away to much and avoid a loose ipad fitting. Using a marker helps mark the areas needed for adjustment trimming. TIP: Use a straight edge and clamp for a more perfect cut.
Next I used very fine sand paper to soften the sharp edges and cut edges of the panel. This created a nice manufactured appearance and feel.
Next I used a specially formulated acrylic adhesive to join the two panel together. Just apply a few lines and drops of the adhesive. Avoid applying to close to edge so as not to squeeze out along the edge when sandwiching the two panels together.
Essentially you are finished. The ipad simply dropps into the 1/4" deep void and is secure enough not to wobble around when drawing, and the panel edges are wide enough for your palm to rest while drawing at the edges of the ipad screem. This whole dimension is also a perfect size for your lap and can serve as a surface when on the go.