I have to cut two straight lengths of post formed countertop to make a 90 degree corner. I am planning to use a skillsaw with a very fine tooth blade, straight edge guide, blue tape, etc. (Customer furnished countertop.) Any suggestions?
(Cabinet and Millwork Installation Forum)
From contributor M:
Good luck! Usually this joining technique is done at a countertop shop with what they call a travel saw or a post form top saw. I assume you are talking about a standard 7 1/4 saw? The blade is not big enough to cut the backsplash in one pass. It's possible, but not really the right way to do it. Just take your time. Cut the top upside down, and use a fence. Make sure you clamp everything down.
I have also had to true up my cuts by putting the joint together and running the saw through the kerf again. Sometimes a little back bevel with the old belt sander. Biscuits and cleats to hold it together, or route your own your holes for dog bones (draw bolts). I would much rather have the top precut, but sometimes you've got to do what you've got to do. I would figure about an hour and eight smokes to set up, cut, prep and install. Test your saw on an area that will be the drop off for performance. Slight tipping, dullness of poorly manufactured blades can still chip the PLAM. And sometimes the chipping will only happen on one side of the blade, so pay attention and plan accordingly.
Still my biggest disappointment has been with the actual profiles of the two tops being different. They would not have lined up good even with the factory square cuts. Most of my cutting on countertops is done with down cut jigsaw blades for scribes and sinks and even after scoring the surface, there can still be the occasional chip. It all depends on the "cabinet god" mood that day, and some days I swear that he is out to get me!
Also the major question is 90 the right angle. We install several hundred sets a year and very few times will 90 yield a good install. Try using a Bosch digital angle finder, designed for crown molding, and two straight edges to get the "true average angle" of the walls, then cut your angles.
Here is how I made the cut. Measure and layout the mitre, cover the layout with clear packaging tape on the back side, cover the laminate side with clear packaging tape, flip the countertop over so that the laminate side is down (the saw blade is cutting up), start the cut from the backsplash side, and make the cut in one go. Finish the cut through the back splash with the Japanese hand saw. No chipping of the laminate!
Now for the sad/bad news, forgot to check the runout of the wall. Remember the corner measured 90 degrees (bevel measure had 18 to 24" legs). After cutting and re-cutting the mitre and still not being able to close the gap, we thought to check the square and runout of the room. Duh! The wall had a runout of at least 1"+!
My son was happy (frustrated but happy) and my daughter-in-law is happy with her new kitchen, going from 2 lf countertop to 32 lf of countertop, new window, insulation, airtight wall, new sheetrock walls and ceiling (another story for another time) and paint, new cabinets, dishwasher, sink, 10 new quad outlets, new light fixtures, saved the floor and the stove. All in one week! Not the four days she was promised. Anyway, she let my son and I live to tell the tale.
Just another typical kitchen remodel in a very old house, over time, over budget, overtired. That's my story and I'm sticking to it.