RE: Build with magnets (instead of pins)
My building board is the one that I DO NOT RECOMMEND by Great Planes. I called around to local metal shops and found that I can get a piece of the same metal for less than $10. A sheet of 1/4" x 3' x 6' steel PLATE was about $80. I have no idea if that is a good price or not, because I only called one place to get a rough idea.