Posted by schooner on October 8, 2005, 5:05 pm
Found it at Halifax HD. $9 for the 26" X 8' sheets. They have all the
"Bert Menkveld" <bertATreentronicsDOTcom> wrote in message
Posted by Morris Dovey on October 7, 2005, 2:39 am
Gary (in firstname.lastname@example.org) said:
| Morris -- if you are watching, maybe you can provide a little
| insight on using the twinwall polycarbonate glazing??
The stuff I'm using is called PolyGal
(http://www.polygal.com/HTMLs/subject.aspx?C1011 012&BSP005). I
use it with the channels running vertically. It needs horizontal
support at top and bottom (8' span is no problem) and vertical support
every 2' of width.
The top photo at http://www.iedu.com/DeSoto/collectors.html shows a
6'H x 12'W panel with vertical supports at 4' intervals. This glazing
exhibits a slight bowing; but has held up well since installation a
little over two years ago. Vertical supports every 2' would have
eliminated the bowing and would have helped aesthetically.
I sandwich the PolyGal panels between the wooden panel body and an
piece of flat or angle aluminum with stainless screws through the
aluminum and PolyGal into the wood.
The top two photos at http://www.iedu.com/DeSoto/sc_materials.html
provide a close-up view of a scrap left over from my first use of
twinwall polycarb back in 1980. It's still flexible and doesn't seem
to have discolored with age. I /think/ that sample was cut from a GE
My spec sheet for PolyGal is at the shop; but so I can't provide
melting or kindling temperature info - but I do recall that both
temperatures are fairly high.
DeSoto, Iowa USA
Posted by Gary on October 7, 2005, 9:28 pm
Morris Dovey wrote:
Thanks Morris -- good information.
Do you think that the PolyGal would be OK as a collector glazing if
the collectors were installed on a 45 deg pitched roof? I would
support them on the 2 ft intervals in the direction running up and
down the roof slope, and (say) 3 ft intervals in the other direction.
They would have to take a bit of snow load from time to time.
"Build It Yourself" Solar Projects
Posted by Morris Dovey on October 8, 2005, 12:29 am
Gary (in email@example.com) said:
| Do you think that the PolyGal would be OK as a collector glazing if
| the collectors were installed on a 45 deg pitched roof? I would
| support them on the 2 ft intervals in the direction running up and
| down the roof slope, and (say) 3 ft intervals in the other
| direction. They would have to take a bit of snow load from time to
I'd guess that horizontal supports every three feet would allow it to
support at least enough snow to keep the collector in the dark. I
think I'd worry more about the supporting structure than the PolyGal.
Assuming that you're planning a DHW setup, I can't remember having
seen a critical angle published for polycarbonates. Depending on
latitude, it could make a difference...
DeSoto, Iowa USA
Posted by Brian Graham on October 7, 2005, 6:37 pm
That's a great tip!
Our local glass supplier has a
whole stack (I'm guessing more than 500 sqft) of double glazed glass
that was cut wrong or has blemishs that he is willing to sell very
cheap -- maybe your local dealer does to?