This thread got the ball rolling for me, so I thought I'd share how I went about it. Pretty decent approach for any regular surfboard construction with a plate attachment, although I would think that foil conversion is best suited to rather tough built boards that are some kind of sandwich construction like mine. This is basically done on an outdoor deck space with no tools beyond an electric sander, a drill, and a digital scale for measuring epoxy. Dust masks and gloves of course, but I have no shop, or garage and did it in spare moments when the kids were out. Took just over a week, but could probably be done in 3-4 days.
Basically its a glass patch on the deck (6 layers of 6 oz), a patch of glass on the bottom (9 layers of 6oz) with 1" solid rolled 6 oz glass inserts bonded to both deck and bottom patch. This is a bolt through method with a washer on the deck as to eliminate traction forces within the inserts and fully capitalize on the strength of the " I beam " structure.
board with deck sanded
the bottom sanded... I ended up going a little further up the board than that, but you get the idea.
The inserts were made in a mould made from 1" PVC pipe with end caps. The bolt hole is a small gauge PVC pipe that I wrapped in about 10-12 layers of wet glass before placing in the mould.
Glass then sand
Epoxy with light filler for fairing
sand
and paint
I made sure to use plenty of mechanical bonding filler in the mix to insert the inserts that were mounted on a jig to ensure alignment. Also important to do the inserts when the deck has gelled but not fully cured to get a good chemical bond. All glass is layered in progressively bigger patches in order to properly taper the strength and flex. All tolled, it added about a pound to an already heavy board. It now weighs 9.4 lbs or 4.25 kg.
Turned out well, and killed some time while waiting for the foil!
Much thanks to Bigdog and Tkettlepoint for advice and guidance.
