Slippery glue makes it hard to keep pieces aligned during clamping. Solve the problem with your biscuit joiner.

While laminating two pieces of 34 " medium-density fiberboard (MDF) to make a router-table top recently, I ran into the problem I always run into when gluing two large pieces face-to-face: The slippery glue makes it hard to keep the pieces aligned during clamping.

I solved the problem with my biscuit joiner. I made matching index marks on two adjacent edges of the stacked workpieces, as shown, then cut biscuit slots into the mating faces of the pieces. After spreading glue on the surface, I put a little glue into each biscuit slot, dropped a biscuit into each slot in the bottom piece, and put the top piece in place, fitting it over the biscuits.

Using this technique, there was no slippage during assembly. And I saved time by not having to retrim the edges with my tablesaw.
Jim Morgan, Dickson, Tenn.