Biscuit joiner? Sander?
I thought this was a hand tool thread?
In all seriousness i have used biscuit joiners back when i worked with power tools and they weren't really my thing. They are helpful for aligning long pieces in glue up, but after a while i ditched the joiner and used cauls. For caul's, i just flattened two boards and wrapped them in packing tape so they wouldn't stick to the glue and then clamped them cross grain on the top and the bottom, and this helped prevent cupping from the clamping pressure.