I have only "jointed" one glue up with my track saw. I had to do a single tapered glue up to make this Cottonwood slab deep enough for my cabin countertop. I was concerned it wouldn't be a flush enough cut but it has held up for years. It experiences probably 100 degree temperature changes each year so I was worried about expansion/contraction effecting a less than perfect joint.
Angled joint runs from off the picture in the lower right to underneath about the third wine bottle from the wall.
I also had a badly cupped piece of elm that presented a couple of problems for my plan to turn into a corner bench. First, I was going to lose too much thickness by planing the cup out. I also only had enough length to wrap the corner so I had to cut the miter and flip the fall off piece to match the miter.
So the glue up was going to be the face with the cup facing up and the opposite side of the miter with the cup facing down.
I decided to cut the miter with my track saw on location and was very meticulous at laying out the cut. I knew I had a good chance of screwing things up. But the miter came out fine.
I next used my track saw to make relief cuts on the sides facing down, which gave me enough flexibility to bend the sections flat.
I then clamped old levels onto the panels until they were flat and filled the relief cuts with epoxy. Once the epoxy cured I left the clamped on levels in place and used Kreg HD pocket holes and screws to secure and glue the miter.
So the miter on this bench was cut with a track saw while the slab was still badly cupped. I did no extra prep to the edges before glue up other than basic sanding. I'm happy how it came out.
Pictures before finishing.
