I have a free corian countertop, which is exactly the correct length for my kitchen countertop over my cabinets. However, the integrated sink is in the wrong place. I want to cut off one end and then take that piece and add it to the other end. I have the corian adhesive, which I bought over the internet. Is there anything special I need to do? Do I just put the adhesive on one piece and then butt the other against it? Do I have to clamp them together; if so, how - this is a 10 foot length of countertop? I've read not to wipe the adhesive of when the seams are put together, but let it dry and then sand it? Any special preparation to each end before applying the adhesive - sanding, etc.

Put counter top on saw horses such that it is very stable. Clamp a piece of 3/4 plywood under the counter top at the place you are going to cut. This is to support the piece you are going to cut off such that it does not chip at the last moment. Use an edge guide to make the cut. Set the blade depth to ¼” greater than the thickness of the counter top. Cut with a 40 tooth carbide blade in a circular saw. Cut like you would hardwood. Do not cut to fast and cause chipping. Do not cut too slow and cause burning. Take cut off piece and the plywood to the other end. Clamp plywood to other end. Butt cut off piece to other end and clamp to plywood. Set up your edge guide and cut down the seam between the ends of counter top and cut off piece. This will give you mirror cuts on the counter top and cut off piece. Lightly sand edged of both pieces.

Cut and install a piece of ¾” plywood about 4 to 6” wide across the cabinet top to support the counter top at the seam.

Install counter top using silicone on the top edge of the cabinets. If you are going to use a full sheet of wood underlayment, cut into sections and allow for movement. Wood expands and contracts with changes in humidity. Corian expands and contracts with changes in temperature. Usually these are in contradiction with each other.

Place a strip of aluminum tape on the plywood support. This is to prevent contamination of Corian adhesive.

Place cut off piece on cabinet with about ½” gap between. You can either glue clamping strips to top of counter top and cut off piece using hot glue, or you can drive wedges between wall and cut off piece to clamp together.
Clean the edges with alcohol. Insert Corian adhesive and push pieces together. Clamp with moderate pressure or tap wedges in. Remove squeeze out of adhesive with sharp chisel after dry. Sand seam flush, then sand surrounding area.