Just an idea to run past the experts but would it be at all possible to
screw sheets of that polycarbonate stuff on the inside of glass for
winter protection? If I drilled holes in the sheets and screwed them to
the wood structure would it be better than bubble wrap which is a swine
to re use and clean.

janet
--
Janet Tweedy
Dalmatian Telegraph
http://www.lancedal.demon.co.uk

"Janet Tweedy" wrote in message
...
Just an idea to run past the experts but would it be at all possible to
screw sheets of that polycarbonate stuff on the inside of glass for
winter protection? If I drilled holes in the sheets and screwed them to
the wood structure would it be better than bubble wrap which is a swine
to re use and clean.

You might get a better fit and better insulation of you screw wooden beading
to the frame to hold the polycarbonate in place.

You could then leave most of the beading in place and slide the
polycarbonate sheets in and out.

You would only have to remove enough beading to allow insertion/removal of
the sheets.

However I suspect that if you do your costings you will find that it is
cheaper to use and bin bubble wrap each year than to have a reusable
polycarbonate sheet arrangement.

Rolls of bubble wrap are very cheap, but AFAIK polycarbonate sheets are
quite expensive.

Depends if reuse is more important than cost.

HTH

Dave R

In article , Janet Tweedy
writes
Just an idea to run past the experts but would it be at all possible to
screw sheets of that polycarbonate stuff on the inside of glass for
winter protection?

We did ours with acetate. Have had some problems with cracking as the
greenhouse temperature changes, but on the whole it has been successful,
and has been in place for 14 years. Don't see why you shouldn't do this
successfully with polycarbonate.

If I drilled holes in the sheets and screwed them to
the wood structure would it be better than bubble wrap which is a swine
to re use and clean.

We use bubble wrap as well - we have a series of poles going the length
of the greenhouse, and drape long pieces over these for the winter,
tucking the hanging ends behind the plants at the sides. It doesn't take
more than 30 mins to remove or to put up
--
Kay
"Do not insult the crocodile until you have crossed the river"

Janet Tweedy wrote:
Just an idea to run past the experts but would it be at all possible to
screw sheets of that polycarbonate stuff on the inside of glass for
winter protection? If I drilled holes in the sheets and screwed them to
the wood structure would it be better than bubble wrap which is a swine
to re use and clean.

The main insulating effect comes from the trapped air. If you want to
use anything else then the twinwall polycarbonate is the material of
choice. It is however much more expensive than bubble wrap.

The best tactic it to heat only the end of the greenhouse furthest from
the door and add a curtain in the middle. That way you keep most of the
warm air inside the greenhouse aginst the closed end.

Regards,
Martin Brown

"Janet Tweedy" wrote in message
...
Just an idea to run past the experts but would it be at all possible
to
screw sheets of that polycarbonate stuff on the inside of glass for
winter protection? If I drilled holes in the sheets and screwed them
to
the wood structure would it be better than bubble wrap which is a
swine
to re use and clean.

Double glazing relies on sealing the air between the two panes. If
you decide to go ahead, try to seal your polycarbonate panes with
sticky tape round the edges. In fact, if you use a good quality tape,
you probably don't even need to do any screwing at all.

Franz

Jan
Sounds to me as if you have timber frame greenhouse, in which case you could
use bubble film, but try cutting old hosepipe into 2 inch lengths and
screwing through the middle of these lengths of pipe (1 inch from each
end)so it forms a washer of sorts then screw the bubble to the frame using
them. easy to remove without tearing the film.

Janet,
Some polycarbonate roofing sheet has uv filtration and reflective
qualities to cut down the amount of light, so watch which one you go for.
Another factor is cost, polycarb is more expensive than glass. Cutting to
size is easy as it can be cut with any decent saw. To fix, rather than
screwing, on the assumption that you have a wooden greenhouse, either use
glazing bars (from the same people that sell polycarb) or make some plastic
(or aluminium) clips with a single screw hole long enough to support the
sheet across the join (50mm x 20mm say). The sheets are incredibly light and
strong so won't require much support. Ensure that you seal both ends using
tape, otherwise you will find all sorts of insects getting into the
channels,

regards,

David


"Janet Tweedy" wrote in message
...
Just an idea to run past the experts but would it be at all possible to
screw sheets of that polycarbonate stuff on the inside of glass for
winter protection? If I drilled holes in the sheets and screwed them to
the wood structure would it be better than bubble wrap which is a swine
to re use and clean.

janet
--
Janet Tweedy
Dalmatian Telegraph
http://www.lancedal.demon.co.uk

"David" wrote in message
...
Janet,
Some polycarbonate roofing sheet has uv filtration

No polycarbonate of the thickness encountered in horticultural
applications lets through any UV worth talking about. It is a very
expensive business to make transparent objects which will transmit a
substantial amount of UV. Fused quartz is the sheapest one. So, for
any horticultural purposes, you can forget about UV light penetrating
into the interior of the greenhouse or tunnel, whatever they may be
made of. Anybody who waffles of UV filtration in polycarbonate
roofing sheet is therefore performing a con trick.

and reflective
qualities to cut down the amount of light, so watch which one you go
for.

For a transparent material which does not have a surface bloomed to
the accuracies of typical light wavelengths, there is a one-to-one
correspondence between the reflection coefficient and the refractive
index. All transparent polycarbonates have the same reflection
coefficient to within a gew percent. They wiol therefore all have
thsubstantially the same reflection coefficients. How then does the
manufacturer achieve the reflective qualities of which you speak?
Oncd again, I suspect a rip-off.


Another factor is cost, polycarb is more expensive than glass.
Cutting to
size is easy as it can be cut with any decent saw. To fix, rather
than
screwing, on the assumption that you have a wooden greenhouse,
either use
glazing bars (from the same people that sell polycarb) or make some
plastic
(or aluminium) clips with a single screw hole long enough to support
the
sheet across the join (50mm x 20mm say). The sheets are incredibly
light and
strong so won't require much support. Ensure that you seal both ends
using
tape, otherwise you will find all sorts of insects getting into the
channels,

Yes. The sealing of the open ends is very important also to prevent
the ingress of water, which would encourage algal growth inside the
cells of the double walls.

Franz

"Franz Heymann" wrote in message
...

"David" wrote in message
...
Janet,
Some polycarbonate roofing sheet has uv filtration

No polycarbonate of the thickness encountered in horticultural
applications lets through any UV worth talking about. It is a very
expensive business to make transparent objects which will transmit a
substantial amount of UV. Fused quartz is the sheapest one. So,
for
any horticultural purposes, you can forget about UV light
penetrating
into the interior of the greenhouse or tunnel, whatever they may be
made of. Anybody who waffles of UV filtration in polycarbonate
roofing sheet is therefore performing a con trick.

and reflective
qualities to cut down the amount of light, so watch which one you
go
for.

For a transparent material which does not have a surface bloomed to
the accuracies of typical light wavelengths, there is a one-to-one
correspondence between the reflection coefficient and the refractive
index. All transparent polycarbonates have the same reflection
coefficient to within a gew percent. They wiol therefore all have
thsubstantially the same reflection coefficients. How then does the
manufacturer achieve the reflective qualities of which you speak?
Oncd again, I suspect a rip-off.


Another factor is cost, polycarb is more expensive than glass.
Cutting to
size is easy as it can be cut with any decent saw. To fix, rather
than
screwing, on the assumption that you have a wooden greenhouse,
either use
glazing bars (from the same people that sell polycarb) or make
some
plastic
(or aluminium) clips with a single screw hole long enough to
support
the
sheet across the join (50mm x 20mm say). The sheets are incredibly
light and
strong so won't require much support. Ensure that you seal both
ends
using
tape, otherwise you will find all sorts of insects getting into
the
channels,

Yes. The sealing of the open ends is very important also to prevent
the ingress of water, which would encourage algal growth inside the
cells of the double walls.

What an appalling lot of typos I made.

Franz

"Martin" wrote in message
...
On Thu, 25 Nov 2004 05:00:46 +0000 (UTC), "Franz Heymann"
wrote:


What an appalling lot of typos I made.

Gawd! Even you are starting to notice :-)

How about a nice spelling checker for Christmas?

I keep forgetting to use mine. {:-((

Franz
--
Martin