what I LIKE TO USE is my Benchmade folding knife. Especially after I have sharpened it keenly.
But alas .... it too turns dull in time. (too short a time!!!)
Next favorite, and this lasts longer for the results... a cheap kitchen steak knife, Serrated. About $4 in the supermarkets. (free if you take your wife's without her noticing them slowly dwindling.... he he )
Last but not least ... the hacksaw blade. No handle.
But my favorite of all to use is "Jose". Jose is one of the tinners/ installers and he does a really fine job of insulating ACR with Armor-Flex.
The stuff on this job is One Inch Thick!!! So you can imagine it takes quite a bit of work to get the job done.
If you have a S W Anderson in your area, they sell a specific knife which comes in two diffrent lengths. It is sharp on one side only, with wooden handle. I'm sorry I do not have a part # for you. I have one for about 6 years now. I last pretty long between sharpinings.
Anybody have tips or tricks to get a professional looking joint on a tee? The "fishmouth" joints that Pipe Coverer's make on both Armaflex and Fiberglass are truly a work of art and I can't seem to come close as good of quality.