I purchased a replacement stove top. The opening in the counter is about 3/4 of an inch too small :( How can I cut the existing Corian countertop. My thoughts are: circular saw with a fine tooth blade, such as for cutting plywood. But I think this would generate great amounts of smoke etc. Or, cut with reciprocating saw, I'd have to rent or buy. I would expect less smoke. Does anyone have an idea?

This is probably best done with a router or laminate trimmer and a carbide bit. Both router and the laminate trimmer and the circular saw all share the problem that you cannot get flush up to the back splash or wall. There is a flush cutting attachment for laminate trimmers but they are expensive for shall we say a "one time" use. I would approach this with the router. Glue an edge guide to the counter top with hot glue and route out as much as possible. I would then use a jig or saber saw to finish the cut. A carbide should be used and I don't think that such is available for a jig saw. With the small amount that has to be cut after routing a regular blade should do it. A reciprocating saw will probably be a little too much of a tool unless you are very skilled at using it. I'm pretty good with one and I wouldn't do it, too much blade.

Many thanks for your tips Harold. I'm afraid I don't have a router. The "Skill saw" may crack the counter, and I really don't want that. Though it kind of bugs me, I suppose it's best I just have Home Depot install it for me. :(

Well you could always try the jig or saber saw. Normally Coran is cut with carbide blades but a regular blade will cut it just will dull quickly. Saber saw blades are super cheap. Personally I would try to find someone own my own rather than through Home Depot. I however, prefer not go into private sentiments in a public form.

The challenge is that you need to make a very smooth cut with radiused inside corners. If you make a jagged cut, then it is very likely that a crack will develop in this area. A router with a carbide bit guided by a straight edge is the best technique. The cut edge should be sanded smooth and rounded over slightly. It is also important to apply aluminum heat conductive tape to the edge of the cooktop cutout.

Do not trust appliance installers to do this work properly. I specialize in repairing countertops and have fixed many cracks caused by incompetent appliance installers.

My website, Top Repair - Your Countertops Like New Again. DuPont Corian and Other Brands has lots of information about these sorts of countertop issues.

Jim,

Don't you mean a heat reflective and/or insulating tape like Nomex? We don't want the heat to be conducted to but away from the Corian.

Hello Ken,

Nomex is an "felt type" insulating tape normally used in demanding commercial applications like corporate cafeterias, and also in repair situations where there has been a pattern of heat related failures. Aluminum tapes such as that made by 3M and sold for this purpose are sometimes called "reflective" tapes but that is not their true function. They actually conduct heat AWAY from the hot spots around a burner in operation and disperse this excess heat into the air space beneath the cabinet. They function like the metal vanes on a car radiator. The purpose is to reduce the dramatic temperature gradient within a solid surface material when cooking is going on, and do so quite effectively. It is the dramatic change in temperature over a short distance that builds up excessive internal stresses that lead to cracking.