foam pipe insulation

I'm going to insulate my 1/2" cpvc in my basement. I'm using this balck rubberized foam (like armaflex). Problem is that it is not pre slit. What is the best way to slit it to get a straight line and then seal it? I thought about laying it on the floor and laying a 2x4 edge along the center line and cutting along the 2x4, then taping it with black electrical tape on the ends and in the middle. Thoughts?

The best way to do that would be to return the stuff you have now and buy pre-slit, pre-glued insulation. I'm sure that is not what you wanted to hear but it's better than futzing around.

I'm sure you can get a fairly straight cut by flattening the insulation under the edge of a straight board and then making a horizontal cut along the length of the piece.

Sealing it is another problem. A single strip of tape along the length of the cut would provide the best seal. Electrical tape in 3 places may leave gaps depending on how the insulation fits the existing pipe.

thanks chh, but i can't find pre slit/self sealing...and I have called 3 different major suppy houses here in Atlanta...so I guess I am stuck with slitting and taping it.

That's too bad. The big boxes have it around here. The plumbing supply guys sent me to an insulation specialty outfit when I needed some for odd sized pipe. They had just what I needed but it was $$$ about 5x the big box store.

foam

If you cut it there is a contact cement to glue it together, just like the precut stuff.

hj, what is the contact cement and where can I get it? thanks

if it truly is made for that outside diameter, it will hold its shape very well for a long time after you cut it, and the minor gap of 1/64th" will not be a significant source of heat loss compared to the heat loss at elbows where you will need to cut custom pieces and tape them a lot. So, just cut it any way you like, and tape it enough to make you feel good about its looks, and work on the corners bends and elbows most.

david

thanks david...that is what i will do.