Cooktop opening oversized


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Old 07-16-11, 12:08 PM
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Cooktop opening oversized

I want to install a new induction cooktop where my old 'normal' one was. The cutout dimensions for the new one are 29-1/2 wide by 19-5/16 deep. The current opening is 28-5/8 by 20-1/2. I have a solid, faux corean, countertop. Will the extra large opening front to back be a problem? Can I shim it by gluing 1/2" plywood to the existing countertop? The overall dimensions of the new cooktop are 30-5/16 by 21-5/16.
 
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Old 07-16-11, 02:03 PM
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Welcome to the forums! You may be able to dodge the bullet, but the unit will need to be centered in the hole, front to back. How is the unit held in place? Clips, silicone, etc? All your holding power will be from the sides, so be aware of the movement possibility if it isn't rock solid held in place. Your trim ring will, of course, need to rest on the corian or you will have sagging problems.
 
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Old 07-16-11, 03:28 PM
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The extra depth to the opening won't be a problem if, as Chandler says, you center the cooktop over the opening front to back. You're going to need to enlarge the opening length using a router & straight router bit. A 3/8" diameter single flute bit with 1/2" shank will work nicely. Clamp a straight edge to the top to guide the router. After cutting, sand the edge smooth & round over the top & bottom edge with a 1/16" roundover bit. The opening needs to be taped with 4 mil soft aluminum tape to prevent cracking from the heat. Above all DO NOT use a jigsaw to cut the opening larger. To do so almost guarantees the top will crack.
Don't use anything to fill the extra space front & back. Instead, after the stove is set, run a bead of clear silicone around the perimeter of the stove & allow it to cure. This will hold the cooktop in place. Good luck
 
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Old 07-17-11, 08:11 PM
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Thanks for the advice, and the tips on cutting the corian. The particular unit we are looking at is a Whirlpool which has no ring. Can I lay a partial furring strip of silicone along the front and back edges before setting it in place? That would save my back and neck from getting under the cabinets so much.

How about aluminum duct tape. Will that work as a heat sink?
 
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Old 07-18-11, 09:21 PM
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I don't follow what you mean when you say your unit has no ring. The difference between the overall dimension and cutout dimension is the flange or ring. It overlays the opening and lays on top of the countertop. As long as it's bigger than the opening, there's no problem. Aluminum duct tape may work if it's thick enough. I would apply several layers. Be sure to cover the entire inside edge of the opening and under the entire flange area. Make it as smooth as possible, and trim off excess tape after setting the cooktop. Use a utility knife to score the tape, then remove it back to the flange edge. Then fun the bead of silicone around the perimeter and clean up with denatured alcohol. Good luck
 
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Old 07-19-11, 11:38 AM
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As I understand it, the glass top overlaps onto the counter top w/o a ring. It is large enough, though by only about 3/4 in (21-5/16 overall). I should be able to cut the countertop on the ends to the proper 19-5/16 in. depth so the unit will slip into the "notch" on the sides. If I cut it correctly that should hold the unit centered front to back. A good silicone bead in the existing gap should about do it.

Sound about right?
 
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Old 07-19-11, 12:47 PM
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Don't worry about the gap-it will be covered by the stove flange. Put the silicone around the cooktop after it's installed, not under it. First clean around the stove with denatured alcohol. Using clear 100% silicone, cut the tip square, not angled, and apply the silicone by pushing the tube forward at an angle keeping a small bead ahead of the tip to force it into the corner as you go. Then wet your finger with alcohol and wipe the excess silicone in one pass with your finger. Repeat for all 4 sides. A spray bottle makes it easier to apply the alcohol. You can mist the silicone with alcohol before swiping with your finger to keep the silicone from smearing all over. Then fold up a white paper towel, spray alcohol on it, & clean up the silicone with it. Good luck
 
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Old 07-20-11, 09:50 AM
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I thought I was ready to go, but it seems every time I turn around, something new pops up. I was looking at a Kitchen Aid that is supported by brackets attached at the sides. The brackets are glued to the left and right counter top sides, but the install guide directs that the counter top must be 1-3/16 to 2 in. thick. The counter top is Fountainhead and is only 1/2 in. thick except for the edges where extra material was added for the drop down. I can't find the install guide for the whirlpool I was also looking at.

Is this counter top depth a standard cooktop requirement? If so, how does anyone install one in a solid material counter top?
 
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Old 07-20-11, 10:22 PM
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Cut the ends to 19 5/16" centered in the opening, then cut 2 pieces of wood or plywood 1" wide X 19 5/16" or length of the bracket and glue them vertically at each end flush with the opening. Use silicone and clamp with spring clamps if you have them. Let the silicone cure for 12 hours or so, then glue the brackets in place as directed in the instructions. The cooktop then snaps into place on the brackets to hold it in place. Good luck
 
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Old 07-21-11, 05:12 PM
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OK, new confidence with professional guidance.

Let me just say, as a new member, that the guidance I've received here at DIY . com has been superb.

I can't thank you enough.

Tom

P.S. I'll let you know how it goes.
 
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Old 08-06-11, 06:38 PM
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Piece of cake. Counter top cut beautifully, cooktop dropped right in, no sealant around the edges, though. Instructions were quite specific not to do that.

Thank you all for all the help and expert advice.

Tom
 
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Old 08-07-11, 12:14 PM
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I'm glad it worked out OK for you. It's always good to hear success stories.
 
 

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