The most appalling job requires .......

[mtt.tr]

Would a more coarse blade not get a better cut!

That is about as course as you can get at 250mm.

Tbh the cut is sublime one vavummed off there no marks at all.

 

[Martin Hocking]

Great job mtt that’s a great bit of ingenuity. It’s very first world though!

When I built the Frankenshed at our old rented house I was so tight on cash I made a shonky wooden jig to split a 50mm sheet into two 25mm sheets in strips the width of a handsaw. An absolutely terrible plan! But between that and bits I found fly tipped I managed to jigsaw puzzle insulate the whole 10 x 10.

I would never do that again!

 

[mtt.tr]

Great job mtt that’s a great bit of ingenuity. It’s very first world though!

Absolutely it is, I had planned to spend longer building it time didn't allow.

MK2 will be smarter

 

[Martin Hocking]

Absolutely it is, I had planned to spend longer building it time didn't allow.

MK2 will be smarter.

Sorry I meant first world as in a very posh solution compared to my Stone Age bodging!
I hope I haven’t caused offence, your prototype looks like my finished article…

 

[weldingnovice]

Great idea

 

[KimB]

Matt, I’m disappointed you didn’t spend loads of money on a new tool you can use once. What a disappointment

 

[roblane65]

I did suggest in jest and got

 

[gaz1]

Would a more coarse blade not get a better cut!

a coarse blade gives off too much dust personally id rather use a diamond wheel and circular saw

if anything a meat slicing wheel would be better or a pizza cutter to most people as you can cut it with a long knife

a no teeth tablesaw blade

 

[Turbo]

Am I correct in thinking that you have a modified sawzall blade mounted in a jigsaw, a riving knife welded to a plate screwed to to the jigsaw with a blade guide fitted at the bottom?

 

[mtt.tr]

Am I correct in thinking that you have a modified sawzall blade mounted in a jigsaw, a riving knife welded to a plate screwed to to the jigsaw with a blade guide fitted at the bottom?

It's a jigsaw blade

The rest yes

 

[mtt.tr]

a coarse blade gives off too much dust personally id rather use a diamond wheel and circular saw

if anything a meat slicing wheel would be better or a pizza cutter to most people as you can cut it with a long knife

a no teeth tablesaw blade

Depth sir depth

 

[DAPPH]

For my plastisol insulated roof I carefully made a simple sheet metal type marker gauge with a throat that just fitted the depth of the sheets . Then used straight tongue & groove as a ruler / guide after drawing a fine marker pen straight line along the sheet on both sides then used a 4 inch angle grinder with a Bosch cut all blade in it to cut along the well clamped in place guides . cut the steel from both sides and used an old serrated bread knife to cut the foam insulation

Doing the same using Celotec for the inside of the office roof was a doddle this time I used a hard point saw to follow both of the angle grinder cuts . So was making my thermostatically controlled heated UV growing enclosure , cutting it outside with my back to the wind .

 

[mtt.tr]

Let me introduce you all to MK2

As you can see the blade isn't square to the saw base also it has clearance, the out of square is taken up by slop in the blade in the cutting direction. The clearance is to stop burrs building up.


MK3 ideas to add to the drawing, no intention of going past this one.

Will need to 3d print better dust extraction at some point down the line. Will see how it goes on Monday

 

[MetalMonkey]

I quite enjoy cutting and fitting jablite - a bit like doing a giant jigsaw puzzle. Much more preferable to itchy glass fibre for me.

I just used a length of wood and an old handsaw, but I like that jigsaw idea. Tried it once with a circ saw. That was a mistake, cut ok, but the dust and mess!

 

[Agroshield]

MK3 ideas to add to the drawing...

Maybe add a few holes to the 'keel' so you could move the silver guide upwards for thinner sheets and/or use a shorter blade.

Consider adding springs under the tabs that clamp it to the jigsaw base so the tabs rise as you undo the nuts. Makes it much easier to install.

 

[GRW]

I think that MkII Tool looks like the dogs danglies for the job. Very nice

Idle musing reading through this had me thinking about a giant-bladed oscillating multi-tool version (more whether it'd actually work very well or not, not as a MkIII or anything).

 

[Gareth J]

Our builders made an open plywood frame 100mm and 150mm wide (or whatever thickness the insulation was) with a slot both sides the thickness of a hand saw blade. Put the guide over the insulation and line up the slot with the place to be cut, slot the saw blade in above the insulation and saw down through.

Yes, dust, but less than a motorised tool and the slot guide worked simply and well.

Your setup looks like another level of precision though!

 

[mtt.tr]

I think that MkII Tool looks like the dogs danglies for the job. Very nice

Idle musing reading through this had me thinking about a giant-bladed oscillating multi-tool version (more whether it'd actually work very well or not, not as a MkIII or anything).

It's a notoriously difficult material to cut,
it's full of tension and grabs terribly.
It's falls apart creating the most god awful dust.


I've tried most methods available to cut it, typical thicknesses we cut are are 120-150mm. Less than 100mm you can score and snap.

 

[mtt.tr]

Our builders made an open plywood frame 100mm and 150mm wide (or whatever thickness the insulation was) with a slot both sides the thickness of a hand saw blade. Put the guide over the insulation and line up the slot with the place to be cut, slot the saw blade in above the insulation and saw down through.

Yes, dust, but less than a motorised tool and the slot guide worked simply and well.

Your setup looks like another level of precision though!

I want to get the job done fast and accurate. Any fettling to fit it is dust inducing.
Dust extraction and accurate cuts are the only way.

 

[pressbrake1]

I think houses are suffering from over use of steel because no one knows how to do a proper structural roof . Just put in steel everywhere. I suppose the other cause is weak not tied brick walls , they put thermal bridging ahead of structural integrity