Flattening

Pete Newton came round the other day for a natter. When we went out to the 'shop we had a look at the progress of the Big Woodie. All bits are done but I had'nt done anything with the sole as I've got this bit of glass on order. Anyhow, Pete said that he'd being having a few thoughts about the sole so we put my big steel straight edge against it and it was pretty good, straightish, not in 'wind', acceptable over most of the length...'cept for a little bit of snipe from the P/T which meant that the sole is, in effect....convex...28" and its convex. Bugger.
To cut a long afternoon sideways (a very enjoyable afternoon by the way) Pete took me thru' the metalworkers way of truing to obtain a surface by using a marking medium on a dead flat surface (my long piece of 10mm glass) and then scraping away the high spots, which as he explained, is mighty tedious but safe, so no danger of making the convexity more pronounced. Which is what might have happened had I gone straight onto the sandpaper, which don't really bare thinking about on a plane this big.
After a little bit of experimentation, we found a suitable marking medium. More difficult than you might think as the glass is dead smooth and won't 'hold' a medium very well, but we eventually found something that I hope will work very well. So next task will be to make up a jig to hold the glass (already bought the mdf) so that I can tediously get the sole scraped flat. I'll then be able to just put some 150g paper into the jig just to finish off, and then it's final assembly and finishing.