Wood – the proper glue to use to bond two pieces of plywood together as a substrate for formica

Cutting the countertop to length:

Try making a custom circular saw jig to cut your countertop to size. 3/4" plywood placed together at right angles with a cleat for guiding your saw should give you a straight cut. Assemble the jig with extra material, then cut it to size with your saw for a perfect fit.

Use a saw blade with a high tooth count and cut the counter upside down. That way, the blade teeth are traveling down (but really up) into the counter surface, minimizing chances for chipping out. Start by cutting the backsplash first, with the rest of the counter pointing towards the floor. Then stop and rotate the countertop so it's upside down and finish the cut. Be sure to support the cutoff material so it doesn't break off a chunk of the laminate near the end of the cut.

As @auujay points out, masking tape can also help reduce the likelihood of chipping.

Source: woodworkingtips.com

Cutting the sink hole:

I crawled several forums looking for advice on this one. Some suggested techniques (in the order that I would try them) were:

• Use a jigsaw with a down-stroke blade to cut out the sink hole. By cutting on the top surface, you have a more accurate picture where your sink hole will be, and the downstroke blade will eliminate chip-out. Start each rounded corner with a 1/2" spade bit.
• Use a jigsaw with a metal cutting upstroke blade. The finer teeth will make for slower work, but have less of a chance of chipping.
• Use a circular saw to cut straight sides from underneath the countertop. Flip over and finish the rounded corners with a downstroke jigsaw blade.

Once again, use masking tape for both cut line visibility and to reduce the chance of chipping the laminate. Also remember to support the cutout section to avoid tearing the laminate near the end of the cut.

There is no reason to glue down engineered hardwood floor to an underlayment. This is just for initial aesthetics. The glue will NEVER last (in a residential setting). The only thing the glue will do is give you fits and make your install seem tighter. Within weeks or months the glue will come loose and you will have a floating floor.

Nothing wrong with a floating floor. But the fact is you should be gluing the pieces together, not under them. The big boxes sell the generic engineered wood flooring glue. Buy that and glue your pieces together, not under them. The only time I have seen gluing to the floor to be an option is thin flooring onto concrete for commercial purposes. The only thing I would glue down in someone home is vinyl sheets/squares.