# Best way to cut blueboard insulation



## fabguy01 (Aug 5, 2009)

I'm going to get started insulating my crawlspace with 2" blueboard and was wondeing if there are any good way to cut it? thanks


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## Gooserider (Aug 6, 2009)

Most foams will cut very nicely with a utility knife - use a sharp blade and a straight-edge, score it deeply and then snap along the score line.  Some of the faced boards will also need you to cut along the face on the opposite side to separate the sections.  Not sure about blueboard, but that is what any of the other insulation products I've used did.  (and so does sheet rock, cement board, and many other composite boards of that sort.

If you have to cut small notches or other cutouts, it's a bit trickier, some times you can cut all the way through with a longer bladed knife, or use a very fine toothed hacksaw blade.  

Gooserider


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## Reggie Dunlap (Aug 6, 2009)

Table saw for ripping, utility knife or handsaw for cutting depending on the thickness.


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## pybyr (Aug 6, 2009)

Try to find a "bread knife" that, instead of having fine serrations, has a rounded wavy blade profile-- they work well.  Don't use or borrow a decent knife- for some reason, foam dulls knives to a degree that you'd never believe until you experience it.

Or, if you can get a blade like the Bosch T313AW for an electric jigsaw, it has the same wavy serrations that mow through foamboard really well.  Only place I have found that blade, though, is the one that came with my small Bosch hand-held utility saw:

http://toolmonger.com/2007/09/01/an-inexpensive-but-useful-pocket-hand-saw/

That special wave-ground blade works really well on foamboard even with the hand-held handle.


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## sweetheat (Aug 6, 2009)

we use a lot of it, most is ripped with a crap table saw blade on my contractor saw. dust collector hookup works great, other tools of the trade, wide blade putty knife, hand saws, sheetrock saws for holes, surform, utility knife with a long snap blade. sweetheat


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## velvetfoot (Aug 6, 2009)

I used a router to make grooves for firring strips and outlet boxes and also to for grooves for wire.


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## fabguy01 (Aug 6, 2009)

Have used a utility knife before, works OK but the blade seems like it sticks and wants to do like a perforated cut. Table saw works great but realy messy. any one heard of using a hotwire? a pice of wire with electrical current runing through it?


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## Highbeam (Aug 6, 2009)

I just used the pink XPS board (same as the dow XPS blue board) for concrete forms and had to cut them both the long way, the short way, and also had to cut the tops of all forms at a 45 degree angle so that the floor wouldn't be uglied by the top of the forms. Anyway, a plain jane circular saw worked fine. Don't cut too fast or you'll gum up the blade, just allow the saw to do the cutting.


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## brad068 (Aug 6, 2009)

velvetfoot said:
			
		

> I used a router to make grooves for firring strips and outlet boxes and also to for grooves for wire.



 VF

 You just gave me an idea.  I wonder if you could get a big enough router bit to cut slots for pipe say 1" or 1.5" the sandwich two pieces together to make an insulated box for hot water pipes.  It would be cheap and just think how many feet you could cover with one 4x8x2" sheet. 24' maybe?... supply and return 4" on center.


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## velvetfoot (Aug 6, 2009)

Wait a sec, I just had a flash.
It's been so long that I forgot what I did, duh.
I was going to do the grooves for the firring strips with the router but I found that was pretty tedious.
Still tedious, but less so, I got an inexpensive wobble dado blade for my crappy table saw, and made successive passes.
I'm not sure what the max is, but you could take the board and flip it around (I did that too).
I'd go though a batch of boards, and then start over after adjusting the fence for the next pass 'til I got to 3" or so.
You could put some polyurethane Gorrilla glue or something and put some weights on it for a while .


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## d.n.f. (Aug 6, 2009)

I sharpen a 4" putty knife.  Hone it razor sharp.  Cut along a drywall t-square.
For cutting details I use a bread knife but it does not cut as well.

I tried a saw once.  What a freaking mess.  Maybe if you had some kick ass dust collection system it would be ok.


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## velvetfoot (Aug 6, 2009)

I found that the stuff doesn't travel too far, unless there's a breeze of course.
Stepping in it though, you can track it over the house.
I've tried mounting the table saw blade (not the dado) backwards, which works, but the thing still kicks back.  
I've used pusher sticks to get close to the blade and that helps with the kickback.

I put a few layers in the rim joist area.  I'd think about having a foam guy do that.


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## EatenByLimestone (Aug 6, 2009)

I have a 7tpi Disston that works well.   

Matt


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## fabguy01 (Aug 7, 2009)

EatenByLimestone said:
			
		

> I have a 7tpi Disston that works well.
> 
> Matt


Whats that?


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