Unisaw Torsion Box Fence Table #5: 7 coats of polyurethane and counting.....

The day after my last post, I routed the rabbitt around the edge, and glued in the Bubinga border. I used a block plane and scraper to get it even with the rest of the top. I gave up on sanding out the tool marks from the surfacing operation, thinking the polyurethane would make them disappear. Almost, but not quite.

From what I’ve seen, it appears that the epoxy didn’t actually seal the end grain, it just ran right through it. I applied the first coat of polyurethane very heavy. Two hours later, and I saw that it had all soaked in completely. But it did seal it a bit. Subsequent coats have started to build, but it’s still soaking into the spots from the CA glue. Very, very strange. I was applying one coat, then the next day, sanding smooth, and another coat. After 5 coats, I thought I was getting close. After the 6th coat, I waited two hours, and applied another. Due to the heavier coat, I need to wait a bit longer for it to cure. It looks like it may take up to ten to fully fill all the end grain. Once filled, I’ll wet sand with mineral spirits and 400 grit on a flat block, and finish with 600 grit, for a satiny smooth finish. Then, I’ll throw it back on the CNC, and open up the holes to reveal the 30+ threaded inserts, and remove a little more material around the router plate opening. It wasn’t quite deep enough the first time. 3 coats of poly soaked into the MDF rabbitt, so it should just need a light wipe on coat for the final sealing when re-cut.

While waiting for polyurethane to dry, I figure I should design the cabinet that’ll go under this new top. To get a really good idea of what it’ll look like, I figured I should model the whole saw. Here’s a little bit of AutoCAD work.

-- Gerry, http://home.comcast.net/~cncwoodworker/CNC_Woodworker.html