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Author Topic: Cutting corrugated polycarbonate sheet  (Read 23722 times)
MR GUS
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« Reply #15 on: May 27, 2011, 06:59:08 PM »

there are so many different types of weed blocker you'd be surprised, as a landscaping material there are burying types, covering types etc, woven, fabric, woven fabric.. so do look carefully, i've 3 different types myself, one of which appears to be fabric with glass fibre reinforcement or something, thats definitely a burying type!

google it, someone'll have it as a hobby i'm sure!  wackoold
« Last Edit: May 27, 2011, 07:02:13 PM by MR GUS » Logged

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skyewright
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« Reply #16 on: May 30, 2011, 03:47:10 PM »

Any hints on cutting corrugated polycarbonate sheet as used on greenhouses, etc?
At the risk of totally sidetracking the topic (but I think you have the answers you wanted already anyway?), and just out of interest, if twin-wall polycarbonate had been available at the agricultural suppliers (and reasonably priced) would you have gone for that or stuck with the single wall corrugated?

I ask as I just noticed that back in January 2009 you wrote in another topic:
It's worth experimenting of course, but I suspect that once you start going to triple-wall the losses from the sunlight absorption would exceed the gains by extra insulation.  Some in the US (even in cold and dull parts) prefer single wall because it lets more light in even though it loses more heat.
Do you happen to recall where you saw the discussion about single wall v twin-wall?

Was your local agricultural supplier also able to supply the "wiggle" closure strips to block the ends of the corrugations, or do you have something else in mind for that?
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David
3.91kWp PV  (17 x Moser Baer 230 and Aurora PVI-3.6-OUTD-S-UK), slope 40, WSW, Lat 57 9' (Isle of Skye)
EccentricAnomaly
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« Reply #17 on: May 30, 2011, 06:11:26 PM »

At the risk of totally sidetracking the topic (but I think you have the answers you wanted already anyway?),

Yes, thanks. I've just put a Maplin order in for the same type of rotary thingy as you have. The one on special offer doesn't look too worthwhile given the reviews.

Quote
and just out of interest, if twin-wall polycarbonate had been available at the agricultural suppliers (and reasonably priced) would you have gone for that or stuck with the single wall corrugated?

Part of the game here is to try with various combinations of cover and absorber that come to hand. I think for lightness and so on for the first attempt I'd have stuck with the single-wall corrugated but I'm trying to make it not too difficult to change.

Quote
I ask as I just noticed that back in January 2009 you wrote in another topic:
It's worth experimenting of course, but I suspect that once you start going to triple-wall the losses from the sunlight absorption would exceed the gains by extra insulation.  Some in the US (even in cold and dull parts) prefer single wall because it lets more light in even though it loses more heat.
Do you happen to recall where you saw the discussion about single wall v twin-wall?

I think it was on build-it-solar or somewhere directly linked from it but, sorry, I'm not really sure.

Quote
Was your local agricultural supplier also able to supply the "wiggle" closure strips to block the ends of the corrugations, or do you have something else in mind for that?

Despite the labels on the sheets saying "don't forget your fixings" I forgot to ask. It's possible they don't as they mostly sell this stuff to put skylights in shed roofs: when I asked about it they said "asbestos or tin?" and we talked at cross purposes for a minute or so until the chap twigged and explained that they sell sheets with width/length/pitches to match the typical panels of each type of roof. I assume for that application the end bits wouldn't be needed.

I'm not too bothered, though, as the top end will butt up against a flat surface and the bottom end can be open to act as part of the air inlet. When I get round to getting some insect screen a bit of that will go over it.
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skyewright
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« Reply #18 on: May 30, 2011, 09:20:21 PM »

Quote
Do you happen to recall where you saw the discussion about single wall v twin-wall?
I think it was on build-it-solar or somewhere directly linked from it but, sorry, I'm not really sure.
Not a problem.  Wink I think it may be a matter of horses for courses anyway; local experiments are undoubtedly  a good idea.

With our moderate maritime climate (no lower than -5C this winter) simple temperature differential heat loss may not be so much of an issue as in the parts of the US (or even parts of the Highlands), but one thing that makes me think twin-wall might be a benefit is air movement across the outside skin, for example, last Saturday there was a decent solar resource but there was also a moisture laden wind averaging around 20mph for most of the day right across the wall where the panels would be - I can imagine that leaching heat out of the panels, especially it were raining too (there were times when we had that combination, it was a good day for rainbows!)..

Quote
...the top end will butt up against a flat surface and the bottom end can be open to act as part of the air inlet. When I get round to getting some insect screen a bit of that will go over it.
So you are going for a fresh air intake rather than circulation of indoor air?
I'm sure there is something to be said for less holes in the walls and making any hole through a 2' stone wall is a very different matter to cutting a hole in US style wooden 'siding' walls!

I suppose the ideal would be for a choice of intakes at the bottom, and something at the top  that could be opened for the height of summer to allow 'dumping' of unneeded heat, but that is perhaps getting too complicated, of at least too far ahead...
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David
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EccentricAnomaly
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« Reply #19 on: May 30, 2011, 10:19:33 PM »

So you are going for a fresh air intake rather than circulation of indoor air?

Yes. Circulation would be good but...

Quote
I'm sure there is something to be said for less holes in the walls...

I think my landlady would agree. The idea here is something completely non-invasive that just leans up against the outside wall of the house to pick up a bit of warmth and some experience.

Quote
I suppose the ideal would be for a choice of intakes at the bottom, and something at the top  that could be opened for the height of summer to allow 'dumping' of unneeded heat, but that is perhaps getting too complicated, of at least too far ahead...

For the eventual system I have something like that in mind but quite how it all interacts with MHRV, etc, will need a bit of experimentation. For an east facing wall in NE Scotland I'm not sure a dump will be will needed though. Stagnation shouldn't do much harm I expect, particularly with single wall - might be more of a problem with double.
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skyewright
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« Reply #20 on: May 31, 2011, 09:49:58 AM »

For the eventual system I have something like that in mind but quite how it all interacts with MHRV, etc, will need a bit of experimentation. For an east facing wall in NE Scotland I'm not sure a dump will be will needed though.
Not often, for sure.  Grin

Stagnation shouldn't do much harm I expect, particularly with single wall - might be more of a problem with double.
I'm not thinking of anything fancy or automatic, more likely just something like a well insulated (and waterproofed!) 'plug' that could be removed as a seasonal change and swapped over for something the same size but with a vent mesh (and rain shield)?

Something 'simple' (hysteria, when is anything ever simple!) like that at the bottom might give the option of bringing in warmed fresh air in the shoulder months, with a change to recirculating in the winter when the outside air was colder and there was less solar energy to heat it up.
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David
3.91kWp PV  (17 x Moser Baer 230 and Aurora PVI-3.6-OUTD-S-UK), slope 40, WSW, Lat 57 9' (Isle of Skye)
EccentricAnomaly
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« Reply #21 on: May 31, 2011, 04:03:44 PM »

Yesterday I wrote:

Quote
For the eventual system I have something like that in mind but quite how it all interacts with MHRV, etc, will need a bit of experimentation. For an east facing wall in NE Scotland I'm not sure a dump will be will needed though.

I had a browse around last night seeing if anything would remind of where I saw those comments about single and double wall insulation. I re-read various things by Gary Reysa, Laren Corie and Nick Pine (Google fodder) who all use single wall in various places but didn't come across anything specific. They all have quite a lot of experience of this sort of thing and both Gary and Nick like doing proper instrumented experiments so it's a bit surprising there's nothing written up.

However, reading some messages by Nick Pine I was reminded of one reason why venting might not be the best solution. By, instead, covering the panels in sunny weather (he suggests 80% shade cloth) you extend its life by protecting it a bit from UV.
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skyewright
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« Reply #22 on: May 31, 2011, 06:30:04 PM »

I had a browse around last night...comments about single and double wall insulation...so it's a bit surprising there's nothing written up.
I tried a "+single +twin" search within Build It Solar and came up with the same result, i.e. both get mentioned but no direct comparison, even on the page where glazing materials are compared.

However, reading some messages by Nick Pine I was reminded of one reason why venting might not be the best solution. By, instead, covering the panels in sunny weather (he suggests 80% shade cloth) you extend its life by protecting it a bit from UV.
Good idea. Nice and simple to implement, and no extra holes in the collector that might let water in and air (heat) out...

I already use spare bits of windbreak (the green 'knitted' stuff) as shading on our cold frames. Easy to rig up on a few hooks plus a few tie backs. I think it's only  60% or maybe even 40% shade but that's may be quite dense enough for high 50's latitudes.  Wink
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David
3.91kWp PV  (17 x Moser Baer 230 and Aurora PVI-3.6-OUTD-S-UK), slope 40, WSW, Lat 57 9' (Isle of Skye)
EccentricAnomaly
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« Reply #23 on: June 01, 2011, 05:20:44 PM »

Ordered the rotary tool from Maplin late on bank-holiday Monday afternoon, it shipped sometime in the middle of Tuesday and arrived earlier this afternoon (+1 for Royal Mail in the Highlands - couriers would have taken another day or two in my limited experience). It's a bit wet and windy for working properly, even in the shed, but I had to give it a try and it tidied up my previous attempt very nicely. Thanks for the advice, all.
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MR GUS
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« Reply #24 on: June 01, 2011, 06:20:16 PM »

Small rotary tools, you can't beat em! ..just be careful with those hands & fingers.
What sort of bits & bobs came with it?
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Austroflamm stove & lot's of Lowe alpine fleeces, A "finger" of Solar Sad
Noli Timere Messorem
Screw FITS ..it is, & always has been about the environment (said the penny-pinching Scotsman)
skyewright
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« Reply #25 on: June 01, 2011, 06:36:47 PM »

..just be careful with those hands & fingers.
...and eyes.

A while ago I was (mis)using one of the little cutting disks to do a job it was not really designed for and a bit flew off. I was very glad I was wearing eye protection!

« Last Edit: June 01, 2011, 07:13:17 PM by skyewright » Logged

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David
3.91kWp PV  (17 x Moser Baer 230 and Aurora PVI-3.6-OUTD-S-UK), slope 40, WSW, Lat 57 9' (Isle of Skye)
EccentricAnomaly
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« Reply #26 on: June 01, 2011, 11:11:08 PM »

Lots of bits and bobs: haven't really explored yet, just used a cutting disk. No instruction manual beyond some boilerplate text telling you not to use it in a tiger enclosure, etc.

Yes, I'm fairly cautious with power tools. One reason for not doing more this afternoon was the need for daylight outside the shed (or a few more bulbs) to see clearly enough for accurate and safe cutting with eye protectors over my varifocals.
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MR GUS
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Officially "Awesome" because Frotter said so!


« Reply #27 on: June 01, 2011, 11:56:03 PM »

http://www.dremeleurope.com/dremelocs-uk/category/2735/accessories

this is very useful for working out your requirements with different materials...
Your basic accy's will obviously just clamp on.
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Austroflamm stove & lot's of Lowe alpine fleeces, A "finger" of Solar Sad
Noli Timere Messorem
Screw FITS ..it is, & always has been about the environment (said the penny-pinching Scotsman)
EccentricAnomaly
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« Reply #28 on: June 06, 2011, 10:08:47 PM »

Was your local agricultural supplier also able to supply the "wiggle" closure strips to block the ends of the corrugations, or do you have something else in mind for that?

Was down that way today so dropped in and asked. Yes, they do supply them for the standard size corrugations but didn't seem to have any for the "mini-profile" stuff I have.

The basic box is working quite nicely (saw 50 C and a steady trickle of air out the top in cloudy/bright conditions with very light drizzle this morning - other notes on my blog) so I now have to think about ducting the output into the bathroom window. I was thinking of using wiggle strips for this part but will now have to think of something else. Squirty foam, perhaps.
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skyewright
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« Reply #29 on: June 07, 2011, 09:21:19 AM »

...other notes on my blog...
Interesting read. Thank you.

PS. Last year seemed to be very 'good' for voles around here...

PPS. The PS. will only make sense if you read through the blog...  Wink

PPPS. There is a link to the blog in the first post on this topic.
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David
3.91kWp PV  (17 x Moser Baer 230 and Aurora PVI-3.6-OUTD-S-UK), slope 40, WSW, Lat 57 9' (Isle of Skye)
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