Replies

1. 
   Rockmanblue | Jan 12, 2009 12:48am | #1

   You can buy fittings molded from expanded polystyrene at most big box stores.  I have tried to hand cut the neoprene rubber sponge ( the black flexible insulation) but have had limited success.

   RMB

1. 
   sunsen | Jan 12, 2009 12:50am | #2

   Thanks, I didn't know that. The guy down at the local Woodcraft store says people use bread knives. Even electric ones. I didn't know that either. I'll have a look into those fittings.

2. 
   DanH | Jan 12, 2009 01:17am | #3

   Try a pair of utility scissors for cutting the stuff. Depending on the weight of the stuff used it might work.

   God is REAL, unless explicitly declared INTEGER
3. 
   Jeff_Clarke | Jan 12, 2009 05:46am | #4

   You're talking about Armacell's Armaflex - great product.    http://www.armacell.com/us

   View Image

   While the adhesive edge type works well, the trick to making it work around elbows and bends is to use black cable ties to keep it closed - without binding it too tightly.

   Jeff

4. 
   Justin Cooke | Jan 12, 2009 10:48am | #5

   Hi,

   You may want to try an auto-service radiator hose cutter if you can find/buy one. It's a rather specialized car tool, but is designed to make very clean, straight cuts in tough hoses. I used one for years when I used to work on cars. I don't really know if it's what you need for pipe insulation, but it seems it would do the trick (if you can find one :) ). (This would probably only help with the miters.)

   Here's a link to one made by Lisle, just to give you an idea of what it looks like: http://www.lislecorp.com/tool_detail.cfm?detail=23

   Good luck,
   Justin

5. 
   DaveRicheson | Jan 12, 2009 02:21pm | #6

   Filet knife and keep a sharpening stone handy.

   I worked with a couple of union insulators on a job last winter. They let me try my hand at a few cuts while they supervised. The long blade sharp knife make all the difference. They both kept a long handled wet stone near by. At the first sign of the knife dragging in a cut they would strop the stone a few time and go right back to it.

   They even wrapped a 400 gallon water tank with foam sheets. It was one of those tanks that was rounded on both ends, so they had compound curves to deal with and multiple pipes and legs welded to the thing. After they were done it was hard to find a seam.

   Rubatex is the adhesive you want to use. These guys never use a plastic wire tie. Just cut, cope and glue.

1. 
   sunsen | Jan 13, 2009 07:39am | #7

   Thanks everyone. Interesting suggestions.

   I figured I'd try the serrated knife trick and see how that goes. It would be pretty easy to make a wooden miter box for it. Also, I'm thinking I could use a hole saw and cut the ends of the miter box to the radius I want and use it as a jig for the coping aspect of the job. This might even work.

   The job I saw that looked so clean used ties in the manner suggested here. I'm thinking I'll go that route too.

1. 
   Riversong | Jan 13, 2009 08:25am | #8

   I figured I'd try the serrated knife trick

   A thin, sharp non-serrated knife is best (the serrations will tear the foam). This is really a very easy job to do neatly. Just practice a bit and you'll get it. 

   Riversong HouseWright

   Design *  * Build *  * Renovate *  * ConsultSolar & Super-Insulated Healthy Homes

6. 
   Jeff_Clarke | Jan 13, 2009 09:17am | #9

   This will work for you:  View Image

   http://www.olfa.com/UtilityKnivesList.aspx?C=39

7. 
   fingers | Jan 16, 2009 12:36am | #10

   A friend of mine owns a large insulation company that does industrial/commercial, marine, and residential.  (in fact he just bought his 4th foam truck to the tune of 250K each)  Anyway, he helped me insulate all the copper in my basement, and wrapped a sedimentation tank.  For the hot lines he used a white fiberglass insulation tube with a self adhesive strip on it.  To cut it we used serrated stainless knives (about 7 or 8 inch blade length) made by Dexter I think.  They were nothing special, kitchen grade stuff.  For the cold lines we used the black sponge stuff described here also with a self adhesive strip down it.  To cut that we used carbon steel knives (about the same length blade) and kept a coarse sharpening stone handy.

   When I mistakenly used the serrated knife to cut the black stuff it tore it very roughly.  The micro serrations from the coarse sharpening stone on the carbon steel knives cut very cleanly thru the black sponge tubes.

   For 90 elbows he had plastic shells stuffed with loose fiberglass for the hot.  You sort of fit them around the copper elbow then held the two halves of the shell together with a ring shank thumbtack.

   For the cold, we just mitered the black sponge tube.  Some times we made the joints look a bit neater with black electrical tape. Not too tight though.

   Hope this helps.

1. 
   gigi | Jan 16, 2009 05:43pm | #11

   i use 2" tin snip's they cut thru with one cut.45's and 90's.they also work great for cuuting to fit around shutoff's and tee's.