I’ve been asked to make a box to hold a venerable Mah Jong set. Thankfully the client isn’t in a hurry, because I’ve been struggling with the perennial problem of a nice piece of timber, bought from a reputable yard, measuring eight per flipping cent moisture content for heaven’s sake, twisting and writhing like a hungry python when I cut it into boards of the required width.
So I thought, well, plywood doesn’t do that (unless I leave it in a damp shed and then who can blame it?) but I don’t want to encase this ancient Mah Jong set in a plywood box. I could maybe make my own plywood so the whole thing looks more craftsmanlike. Then I remembered an article in a (luckily British) woodworking magazine by a real craftsman called David Oldfield. about sawcut veneering, and revisited the article. It turns out that it’s perfectly respectable to use good quality plywood as your substrate, and put your thick (3-4mm) bandsaw-cut veneers either side of it (which you can bookmatch and all sorts).
My planer/thicknesser only goes down to 5mm, but that’s OK because if I cut a piece thinner than that it can always go through the thicknesser after it’s been stuck to a piece of 6mm Baltic birch plywood. And I’m starting to get the hang of resawing on the bandsaw, thanks largely to a wonderful resaw guide by Magswitch – spensive but what a difference!
Anyway, so the aforementioned twisted boards aren’t so bad when a) sawn in half lengthwise and b) sawn in half widthwise with a view to bookmatching and c) glued to a nice piece of 6mm birch plywood. That’s the plan anyway, watch this space.
I’ve discovered rub joints – gluing without clamps!! This I did find in a magazine article (the one about sawcut veneers as a matter of fact), and it’s worth ranting about here because it has saved a massive amount of time and there is none of the clamp drift that I mentioned last month. I can make a dozen of these joints in an hour; the old way would have needed 36 clamps, which I simply don’t have, and probably at least two hours.
When all you’re doing is gluing flat pieces of plywood together you don’t need to clamp them, just keep moving the pieces against each other until it ‘grabs’ – that is, it stops sliding easily. Then don’t move it any more, because that will weaken the bond by breaking the structure of the glue (if that makes sense). So keep the movements small; you soon get the idea of how long it takes before you have to have the pieces aligned how you want them so that it will grab just when you want it to. In this case I’ll be using the sander to tidy up the fretsaw inaccuracies so obviously the closer the better but a hairswidth out isn’t critical.
Also a tip about the glue squeezout – all the books I’ve seen will tell you to wipe off excess with a damp cloth while the glue is still wet. This is because the glue is water soluble. This means that when you wipe it with a damp cloth you get more diluted glue wiped over a larger area, and that will show when you put the finish on. I mean I sanded the last one and sanded again and sanded again and still there were these white marks where this finely diluted glue that was deposited by the damp cloth had insinuated its way into the wood. So here is a better idea – leave it like you see it in the photo, with the beads of glue sitting there gradually getting harder. Go back to it half an hour later, and poke at it with a screwdriver (or your favourite scraping tool – mine happens to be a palette knife). If it’s rubbery but not leaking liquid glue, that’s the time to take the scraper to it and remove the beads. If you leave it longer you can still remove the beads but you’ll need something sharper and then you’ll be in danger of cutting where you don’t want to cut.