Cutting insulation

[Ermz]

So I'm getting a fairly large order of 15 2.4m x 1.2m insulation panels in. I'll need to cut about 9 of these down to 60cm x 60cm x 85cm triangles to use as superchunks.

What is a good tool and/or method to cut insulation straight? The company recommend an angle grinder but that feels like severe overkill. The insulation is 48kg/m3 and polyester-based.

Any advice would be greatly appreciated. Thank you.

[Nordenstam]

A serrated blade should work well.

[macc]

Electric carving knife!

Best investment for the job by a mile. Like a hot knife through butter.

[Ermz]

Thank you very much!

[Nordenstam]

Does the electric knife make neater cuts than by hand?

[macc]

If you hold a straight edge (bit of wood) against the panel you can get very clean cuts. Cutting by hand always seems to make the fiberglass fragment/fluff up and all that. Especially with 4" panels. If you take your time you can make super clean and neat cuts with the electric knife.

The knife also makes things very fast. I always seem to end up have a bit of a 'Vietnam flashback' and not getting perfectly straight edges, but hacking my way through more fibreglass than I need

[Weasel9992]

The electric knife is a great idea...it'll work great. If you can't do that then a bread knife will work fine. Don't forget to wear long sleeves and gloves.

Frank

[DanDan]

I bought an electric knife recently on the basis of the many recommendations around here. I found it to be absolutely useless. Maybe it was too small or underpowered or what ever but no good definitely. I note some much larger more powerful products recommended here, plus a knife. Cutting*|* HOMATHERM
Speaking of which, a large serrated breadknife works very well. Try to find one which has equal serration on both sides, most are lopsided, scalloped only on one side. This makes the cut lean one way.
DD

[AwwDeOhh]

If this is Fiberglass boards +1 on Long sleeves and Gloves. You will probably want to wear a dust mask approved for blocking insulation too.
It's nasty until it's covered.

When you're done working on the material (do it outside, like in a garage or something)
Wash off with COLD water. This will keep your pores closed and avoid any excessive itchy rashs.

[macc]

Originally Posted by DanDan

I bought an electric knife recently on the basis of the many recommendations around here. I found it to be absolutely useless. Maybe it was too small or underpowered or what ever but no good definitely. I note some much larger more powerful products recommended here, plus a knife. Cutting*|* HOMATHERM
Speaking of which, a large serrated breadknife works very well. Try to find one which has equal serration on both sides, most are lopsided, scalloped only on one side. This makes the cut lean one way.
DD

I've got one of these:

Unexpected error occurred - Tesco.Direct

It works a treat, seriously. Cut loads of insulation with it.

[Wiz_Oz]

I have 12 sheets of tontine acosutisorb3 I have to cut up...after searching around, I went to Bunnings here in OZ and bought a cheap Ozito angle grinder and a metal cutting blade....I cut some this afternoon, it went like a hot knife through butter...

The only problem , is I can see its gonna create a hell of a mess....

cheers

Wiz

[Rossome]

Breadknifes work amazing for cutting rockwool. Not sure how it does with rigid fiberglass though.

[Ermz]

I got an electric knife, and while it does the job, it's a little too underpowered to really cut through it. I can imagine an angle grinder would do the job way more efficiently, if not a little *too* efficiently.

Regardless most of the panels have been cut up, but the electric knife certainly had its share of overheating getting them there.