How do you cut sheeps-wool loft insulation?

[Dave Rove]

How do you cut sheeps-wool loft insulation?

100mm Thermafleece loft insulation to be precise. Large scissors are
stopped dead. A Stanley Knife just scrapes small lumps from the
surface. Even a single-edge razor blade from a windscreen scraper just
glides over it. It can be torn, but very untidily.

Finally, I put down two boards with a couple of millimetres gap between
them, laid the insulation across them, placed two matching boards across
the top, stood on the upper boards to compress the insulation, trying not
to wobble and needing several attempts to get the alignment right, then
cut between the gap with a large sharp straight-edge carving knife. That
worked.

So now I'm intending to build a cutting jig so that I can do the above
without falling through the roof. But am I missing something? Should it
really be that difficult?

(I had previously asked this group about putting extra insulation under a
section of flat-roof but was dissuaded by warnings about moisture so I'll
think about that another day. However, sheeps-wool insulation was
mentioned, and that seemed an excellent choice for replacing the dirty
old itchy 1" mineral-wool insulation in the main part of my loft.)

[Andrew Mawson]

"Dave Rove" wrote in message news:pan.2014.02...@dr.invalid...

Good luck chum :)

When tidying up our ewes before lambing they have to be 'dagged' which is
trimming the (usually shit encrusted) wool from their rear ends. For this we
use 'dagging shears' . Dagging shears need sharpening VERY often as you get
through the flock, so good luck getting through 100 mm thick compresed
stuff.

Sheep shearing uses a shearing head very similar to the one used by your
barber - though the good ones are self sharpening. However there you are
cutting at approximately 90 degrees to the wool staple and it is being held
firmly at the other end by the animal !

Andrew

[stuart noble]

I'd try a handsaw

[Tim Lamb]

In message <pan.2014.02...@dr.invalid>, Dave Rove
<da...@dr.invalid> writes

>How do you cut sheeps-wool loft insulation?
>
>100mm Thermafleece loft insulation to be precise. Large scissors are
>stopped dead. A Stanley Knife just scrapes small lumps from the
>surface. Even a single-edge razor blade from a windscreen scraper just
>glides over it. It can be torn, but very untidily.

Cut it with a sharp blade while it is still rolled up? Only done this
once myself and that was rock wool. I actually used a bow saw with the
teeth ground off the blade to leave a reasonably straight sharp edge.
You need the ubiquitous angle grinder:-)

>
>Finally, I put down two boards with a couple of millimetres gap between
>them, laid the insulation across them, placed two matching boards across
>the top, stood on the upper boards to compress the insulation, trying not
>to wobble and needing several attempts to get the alignment right, then
>cut between the gap with a large sharp straight-edge carving knife. That
>worked.
>
>So now I'm intending to build a cutting jig so that I can do the above
>without falling through the roof. But am I missing something? Should it
>really be that difficult?
>
>(I had previously asked this group about putting extra insulation under a
>section of flat-roof but was dissuaded by warnings about moisture so I'll
>think about that another day. However, sheeps-wool insulation was
>mentioned, and that seemed an excellent choice for replacing the dirty
>old itchy 1" mineral-wool insulation in the main part of my loft.)

--
Tim Lamb

[Dave Liquorice]

On Mon, 10 Feb 2014 17:41:21 +0000 (UTC), Dave Rove wrote:

> How do you cut sheeps-wool loft insulation?

<snip>

> Finally, I put down two boards with a couple of millimetres gap between
> them, laid the insulation across them, placed two matching boards across
> the top, stood on the upper boards to compress the insulation, trying
> not to wobble and needing several attempts to get the alignment right,
> then cut between the gap with a large sharp straight-edge carving knife.

I think that is the only way compress between boards. If you have a
couple of clamps and thickish boards it might be easier to clamp the
wool between the boards and use them as a guide for the knife, a
scolloped edge might be better than straight.

--
Cheers
Dave.

[Bill Wright]

Dave Rove wrote:
> How do you cut sheeps-wool loft insulation?

An electric kitchen knife of the type that has two opposing deeply
serrated blades.

Bill

[PeterC]

When I was cutting the glass insulation for my loft I found that an old
Kitchen Devil, with the scollops worn down to undulations, well sharpened
was easy to use. I cut the rolls before unwrapping them - don't need to be
dead accurate of course.
With only a 10" blade, the main skill is in avoiding the dreaded spiral!
--
Peter.
The gods will stay away
whilst religions hold sway

[Dave Rove]

On Mon, 10 Feb 2014 17:41:21 +0000, Dave Rove wrote:
> How do you cut sheeps-wool loft insulation?

Thanks for the comments. I decided to go with making a cutting jig:

http://imgur.com/a/rZM5R

A powered kitchen knife would have worked I'm sure, but I might have
bought the wrong type and blown it up.

[Brian_Gaff]

Well there are people here who would answer Angle grinder even if the
question was about brain surgery!

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Dave Rove" <da...@dr.invalid> wrote in message
news:pan.2014.02...@dr.invalid...

[Martin Bonner]

On Monday, February 10, 2014 5:41:21 PM UTC, Dave Rove wrote:
> How do you cut sheeps-wool loft insulation?

A board of wood underneath, a board on top, cut along the edge of the boards with a carving knife.

In other words, your original scheme, but only one board top and bottom.

[Bill Wright]

Martin Bonner wrote:
> On Monday, February 10, 2014 5:41:21 PM UTC, Dave Rove wrote:
>> How do you cut sheeps-wool loft insulation?
>
> A board of wood underneath, a board on top, cut along the edge of the boards with a carving knife.

Forget the carving knife. Use an angle grinder with a thin blade. Or a
stil saw.

Bill