Cutting corrugated polycarbonate sheet

[EccentricAnomaly]

Any hints on cutting corrugated polycarbonate sheet as used on greenhouses, etc?

Attempts today with small handsaw, jigsaw with various blades, big and little (though somewhat blunt) hacksaws and even a bread knife all resulted messy cuts with cracking. Googling resulted in suggestions of a fine bladed saw and doing in the warm (bit awkward - though could perhaps warm the sheets inside then take them out and cut them immediately). Any other ideas?

It's for a solar warm air panel, by the way.

[MR GUS]

You need a dremel sir! go look a ttheir website, then if you have a focus (gone down the pan) you may fiind a good price, they're in liquidation.
incredibly handy tools!

[Sean]

google fein tool - every man should have one

[Brandon]

will it cut using the back of a panel saw as a guillotine?  we used to cut corrugated tin roofing like that hammer a fat nail into the end of one side of a saw horse, hook the hole in the end of the saw over the nail (teeth to the sky) and place the tin on the saw horse, with your mark under the back of the saw, just as you would with a slate guillotine.

[billi]

guess i would try an angle grinder with a thin steel disc on ...

But  as said only a guess

Billi

[rogeriko]

Angle grinder with thin disc cuts/melts plastic perfectly correx too

[MR GUS]

..YES A DREMEL CAN DO THAT!

Plenty of bits & bobs to cut plastic, finely not rip it apart, i'v cut letterboxes & the likes out, guttering, poly carb, the control of the rpm is handy & tool small enough to give full visibility as to chasing the line, 2 handed job as they are more powerful than one assumes & cows if you let it slip out of your hands (fingers)
i'd probably opt for a larger grinding disc (around 32 mm) what sort of strength carbonate is it? as obviously there are so many!

NB skiltool are a bit bigger but also by Bosch who own / distribute dremel. ...& alot cheaper more often than not.

[MR GUS]

just looked over your pics on the blog, regular polycarbonate stuff, easy a small disc will simply melt in & through without jagging the edges.

To my minds eye dremels ought to be compulsory house kit!

[Richard Owen]

Angle grinder, thin metal blade for me.

All the heated edgy stuff can be pulled off easily with finger and thumb resulting in nice clean edge.

[skyewright]

It's for a solar warm air panel, by the way.

Very interesting. Thank you.

When cutting corrugated polycarbonate a few years ago for an outhouse roof I clamped batons either side to hold it stiff, then used one of those tool that hold a hacksaw blade at one end only. If I'd had thin enough batons I might have tried a fine bladed jigsaw.

I have a similar project in mind for our SSE gable, but it probably won't happen for months[1].

I'm tentatively considering various designs & materials (taking into account the complication that around here you can't simply pop along to B&Q, and lots of suppliers have riders on delivery charges to IV postcodes).

Interesting point about the reflections.

As an absorber, layers of aluminium mesh screen seem to come out well in a recent BuildItSolar study.
http://www.builditsolar.com/Experimental/AirColTesting/Index.htm
Though I imagine you are probably well aware of that study already.  

[1] a) Very busy. b) By later this year we hope to have a conservatory/greenhouse on the front of the house and that should make a good spot for constructing this sort of thing out of the weather.

[skyewright]

google fein tool - every man should have one

Not seen those before.

If I could have spotted an emoticon for drool, I'd have used it. 

[Baz]

Very interesting link to the panel testing.
Problem of course in uk of mesh screen not being cheap readily available material.
I think the superior performance of the 'mesh' wrt the 'backpass' shows that a limitting factor is heat transfer from the collector material (mesh or aluminium sheet) to the air whereas I was expecting the backpass to have an advantage from the insulating air gap between absorber and galss. The solution to this would be creating high turbulance in the airflow but that also increases pressure loss.

[skyewright]

Problem of course in uk of mesh screen not being cheap readily available material.

When I googled 'aluminium fly screen mesh' I was surprised at the number of possible UK sources. As to price, isn't it at least cheaper than alu sheet (even if several layers of mesh are used)?

I think the superior performance of the 'mesh' wrt the 'backpass' shows that a limitting factor is heat transfer from the collector material (mesh or aluminium sheet) to the air whereas I was expecting the backpass to have an advantage from the insulating air gap between absorber and galss.
The solution to this would be creating high turbulance in the airflow but that also increases pressure loss.

IIRC I saw one study where they had improved transfer in a backpass collector by "roughening" the underside of a sheet absorber by attaching a sheet of mesh...

I was considering using greenhouse twin-wall polycarbonate for the glazing, that would give a small insulating air gap above even a mesh collector.

Most likely I'd need to go for 2'x4' sheets because of the practicalities of delivery (and they seem to be a popular unit of sale). I'd assumed 4 horizontal sheets on an 8'x4' box, but with the 'flute' orientation most people seem to offer that would put the flutes horizontal too. Given EA's thoughts on reflections I'm wondering if even with flat twin-wall there might not be advantage in vertical flutes to make the best of the sun as it tracks round?

[EccentricAnomaly]

As an absorber, layers of aluminium mesh screen seem to come out well in a recent BuildItSolar study.
http://www.builditsolar.com/Experimental/AirColTesting/Index.htm
Though I imagine you are probably well aware of that study already.  

I am, indeed. Wire mesh was my plan A but they didn't have anything suitable at the builders' merchants in Thurso (they'd have to order it in from Inverness) and I forgot to ask at the agricultural supplies place I got the polycarbonate from. I've got some black landscape fabric for initial tests but will probably wind up mail-ordering something more suitable. Apart from anything, I doubt that the landscape fabric is that UV resistant - not a lot of point for something that's supposed to be buried - though the polycarbonate should provide some protection.

Bit of window (well, browser tab) shopping for Dremels today. The beefy ones are quite a bit more beefy than I though, it seems - I'd only really come across the little ones. No rush now as I doubt anything would ship before Monday¹ Tuesday so I'll contemplate overnight.

¹ Bank Holiday - gah!

[skyewright]

I've got some black landscape fabric for initial tests but will probably wind up mail-ordering something more suitable. Apart from anything, I doubt that the landscape fabric is that UV resistant - not a lot of point for something that's supposed to be buried

By coincidence I'd also wondered about using that as I have a part roll in the shed (the woven sort as opposed to the felt/'random fibre' version, whatever that's called).

I have some pieces that have been actively used and reused as a "bed not in use" mulch cover on some raised beds for over 10 years now. That's mainly winter exposure but some summer exposure too. Those pieces are certainly are not as black as they used to be, but they aren't fragile either; you still need scissors or a knife if you want to trim off a length, so the UV hasn't destroyed them yet.

Bit of window (well, browser tab) shopping for Dremels today. The beefy ones are quite a bit more beefy than I though, it seems - I'd only really come across the little ones. No rush now as I doubt anything would ship before Monday¹ Tuesday so I'll contemplate overnight.

I have an "Everise" not-Dremel I got from Maplins. It does a lot of jobs very well.

http://www.maplin.co.uk/variable-speed-rotary-tool-and-119-piece-accessory-set-228660

Maplins quite often seem to have these on special offer (or at least with a "free" tool kit). At present they seem to have an offer on a different one:

http://www.maplin.co.uk/18v-rotary-tool-kit-and-61-piece-accessory-set-223458

Not a Dremel, but at £16 not a Dremel price either...