I made up the plans myself. The biggest science to it (and any fretted instrument) is the fret spacing. I bought a preslotted mandolin fretboard from Stewart-MacDonald. But I also found the formula for calculating fret position in a book, so I could have done it myself.

The pie tin is made of light steel, not heavy aluminum or aluminum foil. I got it at a thrift store. I thought it would be strong enough to withstand the string pressure, and light enough to vibrate well, and I am fairly pleased with it (of course my ears are tin too). But I don't actually play it much, being more of a finger picking guitar & banjo type of guy.

Anyone who wants more details can e-mail me at jdwhitney@wpmail.code3.com.