The cover on my 5*10m poly-tunnel (approx) ripped one night in a strong
gale. (right across the circumference, and half way along the length)

Taking some thick twine, and punching holes in each side every 2cm or so,
and then lacing up the split edges has worked well.

Start out with a fairly loose gap, and then you can gradually bring the
edges together.

So far has lasted about 3 months, in fairly strong winds.

Tips.
Use a blunt pointed object to punch the holes - a sharp one will mean
it's easier to tear the string out.

Start with a long length of string - twice as long as you want to work
with, pull halfway through, then work to the ends - this will make
it easier to tighten up later.

I found it easier to lace it so that it on the outside, it looks
like dashes along the sides, with string crossing on the insides
directly across the cut.

I used baler twine, which is a 3mm or so plastic string, which can easily
be melted into a nice point.

Not advocating this, just thought that others might find it interesting.

Tips.
Use a blunt pointed object to punch the holes - a sharp one will mean
it's easier to tear the string out.


Another tip. (But not 'truly' related to the above but does apply)
Any material or metal which is 'tearing', can be stopped going further, by
drilling a hole at the end of the existing tear.

Mike

"Mike" wrote in message
...

Tips.
Use a blunt pointed object to punch the holes - a sharp one will mean
it's easier to tear the string out.


Another tip. (But not 'truly' related to the above but does apply)
Any material or metal which is 'tearing', can be stopped going further, by
drilling a hole at the end of the existing tear.

Some kind of eyelet, even if only one or two washers, would also help to
take the strain on the cord and prevent splitting.

Mary

Mike

Mary Fisher wrote:
"Mike" wrote in message
...

Tips.
Use a blunt pointed object to punch the holes - a sharp one will
mean it's easier to tear the string out.


Another tip. (But not 'truly' related to the above but does apply)
Any material or metal which is 'tearing', can be stopped going
further, by drilling a hole at the end of the existing tear.

Some kind of eyelet, even if only one or two washers, would also
help
to take the strain on the cord and prevent splitting.

I'd guess that you could make very effective eyelets for the purpose
by punching holes in squares of gaffer tape or Duck tape. (Actually,
I'd consider doing the whole repair with this kind of tape.)

--
Mike.

"Mike Lyle" wrote in message
...

Some kind of eyelet, even if only one or two washers, would also
help
to take the strain on the cord and prevent splitting.

I'd guess that you could make very effective eyelets for the purpose
by punching holes in squares of gaffer tape or Duck tape.

Oh yes, of course! I expect I would have thought of that, given time ...

(Actually,
I'd consider doing the whole repair with this kind of tape.)

Looks awful though!

Mary

--
Mike.

Mary Fisher wrote:
"Mike Lyle" wrote in message
...

Some kind of eyelet, even if only one or two washers, would also

help

to take the strain on the cord and prevent splitting.

I'd guess that you could make very effective eyelets for the purpose
by punching holes in squares of gaffer tape or Duck tape.


Oh yes, of course! I expect I would have thought of that, given time ...


(Actually,
I'd consider doing the whole repair with this kind of tape.)


Looks awful though!

You can buy a special tape for this. It is like a very strong sellotape,
at least as strong as Duck tape but clear(ish).

One further thought re making holes for lacing (interesting idea, this).
If you melt the holes (small gas soldering iron?), the plastic will melt
out from the centre, leaving a plastic collar as a reinforcement.


--
Howard Neil

"Howard Neil" wrote in message
...
Mary Fisher wrote:
"Mike Lyle" wrote in message
...

Some kind of eyelet, even if only one or two washers, would also

help

to take the strain on the cord and prevent splitting.

I'd guess that you could make very effective eyelets for the purpose
by punching holes in squares of gaffer tape or Duck tape.


Oh yes, of course! I expect I would have thought of that, given time ...


(Actually,
I'd consider doing the whole repair with this kind of tape.)


Looks awful though!

You can buy a special tape for this. It is like a very strong sellotape,
at least as strong as Duck tape but clear(ish).

"ish" is the operative word. It's not the same colour as the poly and if it
is to start with,in my experience, it yellows.

Lacing is decorative and makes a feature out of a disaster.

One further thought re making holes for lacing (interesting idea, this).
If you melt the holes (small gas soldering iron?), the plastic will melt
out from the centre, leaving a plastic collar as a reinforcement.

Could do, if you're very skilled :-) I wouldn't do it but there again I
never handle a soldering iron of any kind these days.

Mary


--
Howard Neil

Mary Fisher wrote:
"Howard Neil" wrote in message
...

You can buy a special tape for this. It is like a very strong sellotape,
at least as strong as Duck tape but clear(ish).


"ish" is the operative word. It's not the same colour as the poly and if it
is to start with,in my experience, it yellows.

The tape I use is the same colour as the poly and stays the same colour.
I had to apply some about 5 years ago and it is still the same colour
today. There must be different qualities on the market.


Lacing is decorative and makes a feature out of a disaster.

I certainly like the sound of it.


One further thought re making holes for lacing (interesting idea, this).
If you melt the holes (small gas soldering iron?), the plastic will melt
out from the centre, leaving a plastic collar as a reinforcement.


Could do, if you're very skilled :-) I wouldn't do it but there again I
never handle a soldering iron of any kind these days.

I think the word "careful" should replace "skilled". I would not think
there could be much skill at poking plastic with a soldering iron.

--
Howard Neil

"Howard Neil" wrote in message
...
Mary Fisher wrote:
"Howard Neil" wrote in message
...

You can buy a special tape for this. It is like a very strong sellotape,
at least as strong as Duck tape but clear(ish).


"ish" is the operative word. It's not the same colour as the poly and if
it
is to start with,in my experience, it yellows.

The tape I use is the same colour as the poly and stays the same colour.
I had to apply some about 5 years ago and it is still the same colour
today. There must be different qualities on the market.

After the mice ate my tent ( I had to repair a hole in the plastic
windows (it's a big tent). You can get plastic tape for this purpose. So far
it has stayed put and not yellowed. Try a camping shop.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Bob Mannix wrote:
"Howard Neil" wrote in message
...

Mary Fisher wrote:

"Howard Neil" wrote in message
...

You can buy a special tape for this. It is like a very strong sellotape,
at least as strong as Duck tape but clear(ish).


"ish" is the operative word. It's not the same colour as the poly and if

it

is to start with,in my experience, it yellows.

The tape I use is the same colour as the poly and stays the same colour.
I had to apply some about 5 years ago and it is still the same colour
today. There must be different qualities on the market.


After the mice ate my tent ( I had to repair a hole in the plastic
windows (it's a big tent). You can get plastic tape for this purpose. So far
it has stayed put and not yellowed. Try a camping shop.



Maybe I am just missing something here because it's been a while since I
played with poly tunnels but couldn't you just use plastic cement to
glue the parts back together?

--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

"Howard Neil" wrote in message
...
Mary Fisher wrote:
"Howard Neil" wrote in message
...

You can buy a special tape for this. It is like a very strong sellotape,
at least as strong as Duck tape but clear(ish).


"ish" is the operative word. It's not the same colour as the poly and if
it is to start with,in my experience, it yellows.

The tape I use is the same colour as the poly and stays the same colour. I
had to apply some about 5 years ago and it is still the same colour today.
There must be different qualities on the market.


Lacing is decorative and makes a feature out of a disaster.

I certainly like the sound of it.


One further thought re making holes for lacing (interesting idea, this).
If you melt the holes (small gas soldering iron?), the plastic will melt
out from the centre, leaving a plastic collar as a reinforcement.


Could do, if you're very skilled :-) I wouldn't do it but there again I
never handle a soldering iron of any kind these days.

I think the word "careful" should replace "skilled". I would not think
there could be much skill at poking plastic with a soldering iron.

The skill comes in understanding the properties of the material you're
working with, using the right size and temperature of iron for the right
amount of time.

You didn't specify "poking plastic" originally. Is that what you'd do?

Mary

--
Howard Neil

"doozer" wrote
Maybe I am just missing something here because it's been a while since I
played with poly tunnels but couldn't you just use plastic cement to glue
the parts back together?

Problem is that there is no glue or solvent in existence that will glue
polyethylene.

Mary Fisher wrote:

You didn't specify "poking plastic" originally. Is that what you'd do?

Yes. I use the same principle in my veg patch. I cover it with old
silage sheet and make holes with a blow lamp. The sheet melts back to
produce a hard ring and a nice clean hole to plant the veg through. It
is quick and easy to do and I was simply transferring the same idea to
the polytunnel (scaled down, of course). I have some old poly somewhere,
I'll give it a try.

--
Howard Neil

"Toolmaker" wrote in message
...
"
Problem is that there is no glue or solvent in existence that will glue
polyethylene.



How can this be true ?
As a previous poster has said, there is a readily available sticky tape
specifically produced to repair tares in the poly.
I have some and use it with much success.
It is coated with glue which sticks like crazy to the poly.
The adhesive may not be generally available as a stand alone product which
we can buy in tins, but I feel it is untrue to state that there is no glue
that will glue poly(eth?)ythene - or whatever a polytun is constructed with.

Regards
Pete
www.thecanalshop.com

Peter Stockdale wrote:
"Toolmaker" wrote in message
...
"
Problem is that there is no glue or solvent in existence that will
glue polyethylene.



How can this be true ?
As a previous poster has said, there is a readily available sticky
tape specifically produced to repair tares in the poly.
I have some and use it with much success.
It is coated with glue which sticks like crazy to the poly.
The adhesive may not be generally available as a stand alone
product
which we can buy in tins, but I feel it is untrue to state that
there
is no glue that will glue poly(eth?)ythene - or whatever a polytun
is
constructed with.

Perfect logic, but the fact remains that there isn't a glue for
poly[ethyl]ene, which isn't a million miles different from ptfe, the
non-stick frying-pan stuff. It's always joined by welding. The
problem is, I think, that the adhesives on gaffer tape and such-like,
while they will stick well to polythene till they dry out a few years
later, can't be applied in amateur conditions.

--
Mike.

"Mike Lyle" wrote in message
...



Perfect logic, but the fact remains that there isn't a glue for
poly[ethyl]ene, which isn't a million miles different from ptfe, the
non-stick frying-pan stuff. It's always joined by welding. The
problem is, I think, that the adhesives on gaffer tape and such-like,
while they will stick well to polythene till they dry out a few years
later, can't be applied in amateur conditions.

--
Mike.

Yup -but we are talking about repair -not construction.
A repair using the proper tape will outlast the useful life of the poly
sheet.
imho !
pete

"Howard Neil" wrote in message
...
Mary Fisher wrote:

You didn't specify "poking plastic" originally. Is that what you'd do?

Yes. I use the same principle in my veg patch. I cover it with old silage
sheet and make holes with a blow lamp. The sheet melts back to produce a
hard ring and a nice clean hole to plant the veg through.

Actually that's not a bad idea - for a veg patch. I might (albeit
reluctantly) follow your example :-)

However, I think that such holes might be too large for a polytunnel lacing
repair.

Mary

Peter Stockdale wrote:
"Mike Lyle" wrote in message
...



Perfect logic, but the fact remains that there isn't a glue for
poly[ethyl]ene, which isn't a million miles different from ptfe,
the
non-stick frying-pan stuff. It's always joined by welding. The
problem is, I think, that the adhesives on gaffer tape and
such-like,
while they will stick well to polythene till they dry out a few
years
later, can't be applied in amateur conditions.

--
Mike.

Yup -but we are talking about repair -not construction.
A repair using the proper tape will outlast the useful life of the
poly sheet.
imho !

Yes, that's quite right; but I was only answering the question about
why we can't get an adhesive which would work for polythene.

Mary Fisher wrote:
"Howard Neil" wrote in message
...

Mary Fisher wrote:


You didn't specify "poking plastic" originally. Is that what you'd do?

Yes. I use the same principle in my veg patch. I cover it with old silage
sheet and make holes with a blow lamp. The sheet melts back to produce a
hard ring and a nice clean hole to plant the veg through.


Actually that's not a bad idea - for a veg patch. I might (albeit
reluctantly) follow your example :-)

This may be a good time to ask local farmers for their used sheets. They
should now have cleared their silage and they will have to pay to have
the sheets removed. Someone offering to take a sheet off their hands for
nothing will be welcomed.


However, I think that such holes might be too large for a polytunnel lacing
repair.

You haven't seen the size of the laces. :-)

I'll post the result if my experiments tomorrow.


--
Howard Neil

In uk.d-i-y Peter Stockdale wrote:

"Mike Lyle" wrote in message
...



Perfect logic, but the fact remains that there isn't a glue for
poly[ethyl]ene, which isn't a million miles different from ptfe, the
non-stick frying-pan stuff. It's always joined by welding. The
problem is, I think, that the adhesives on gaffer tape and such-like,
while they will stick well to polythene till they dry out a few years
later, can't be applied in amateur conditions.

Yup -but we are talking about repair -not construction.
A repair using the proper tape will outlast the useful life of the poly
sheet.

But would have been impossible.

Given two edges 12" apart, taping it up just isn't going to work.
Lacing it up, and drawing the edges together worked well.
However, the proper tape does well with intermittent loads, but will creep
off the joint if it's under constant tension.

Mike Lyle wrote or quoted:

Perfect logic, but the fact remains that there isn't a glue for
poly[ethyl]ene, which isn't a million miles different from ptfe, the
non-stick frying-pan stuff. It's always joined by welding. [...]

``Polyethylene and polypropylene and nylon are pretty difficult,
because they do not have any pores, and almost no solvents can dissolve
them. Only soft, rubbery solvent-drying glues can work, because glues
can only hang onto the plastic by wetting its surface.''

- http://www.newton.dep.anl.gov/askasc.../chem03271.htm

``8005 - Scotch-Weld? Structural Plastic Adhesive
Two-part structural acrylic-based adhesive (10:1 mix ratio by volume),
that can structurally bond many grades of polyethylene, polypropylene,
and thermoplastic elastomers (TPE's) without any surface preparation at
room temperature.''

- http://www.tapecase.com/tc/prodASP/S...Structural.asp
--
__________
|im |yler http://timtyler.org/ Remove lock to reply.

"Howard Neil" wrote in message
news:4272a654$0$581
Mary Fisher wrote:



This may be a good time to ask local farmers for their used sheets.

I don't know farmers who use them and my garden plots are measured in low
single numbers of square yards, not hectares. And I only have four plots.

They should now have cleared their silage and they will have to pay to
have the sheets removed. Someone offering to take a sheet off their hands
for nothing will be welcomed.


However, I think that such holes might be too large for a polytunnel
lacing repair.

You haven't seen the size of the laces. :-)

Nor have you. He said "thick twine", not "ships' cable".

Mary



I'll post the result if my experiments tomorrow.


--
Howard Neil

Ian Stirling wrote:

I used baler twine, which is a 3mm or so plastic string, which can easily
be melted into a nice point.

....with the aid of a welding torch. Thereby fulfilling the LAW, which
requires ALL agricultural repairs to be made using baler twine and a
welder...

"Stefek Zaba" wrote in message
...
Ian Stirling wrote:

I used baler twine, which is a 3mm or so plastic string, which can easily
be melted into a nice point.

...with the aid of a welding torch. Thereby fulfilling the LAW, which
requires ALL agricultural repairs to be made using baler twine and a
welder...

Sssssssh! If They (spelt defra) hears that they'll devise forms to apply for
its use.

Mary

Tim Tyler wrote:
Mike Lyle wrote or quoted:

Perfect logic, but the fact remains that there isn't a glue for
poly[ethyl]ene, which isn't a million miles different from ptfe,
the
non-stick frying-pan stuff. It's always joined by welding. [...]

``Polyethylene and polypropylene and nylon are pretty difficult,
because they do not have any pores, and almost no solvents can
dissolve them. Only soft, rubbery solvent-drying glues can work,
because glues can only hang onto the plastic by wetting its
surface.''

- http://www.newton.dep.anl.gov/askasc.../chem03271.htm

``8005 - Scotch-Weld? Structural Plastic Adhesive
Two-part structural acrylic-based adhesive (10:1 mix ratio by
volume), that can structurally bond many grades of polyethylene,
polypropylene, and thermoplastic elastomers (TPE's) without any
surface preparation at room temperature.''

- http://www.tapecase.com/tc/prodASP/S...Structural.asp

Good news! (Note that I did mention things which work by wetting will
stick to pe in the part you cut for space.) I wonder what the
smallest available quantity is.

Of course, using it to mend a torn sheet would need you to cut strips
from another sheet, apply the adhesive, and apply them. Ready-made
mending tape still sounds quite attractive!

--
Mike.

Mary Fisher wrote:
"Howard Neil" wrote in message
news:4272a654$0$581

Mary Fisher wrote:



This may be a good time to ask local farmers for their used sheets.


I don't know farmers who use them and my garden plots are measured in low
single numbers of square yards, not hectares. And I only have four plots.


Ask your daughter to obtain some and collect it when you next visit?


I'll post the result if my experiments tomorrow.

I have now experimented and the results were excellent. No skill was
required, even the first hole was perfect.

I used a gas soldering iron (so it could be easily used outside) with a
pointed bit. By poking the poly, a round hole about 5mm across was
formed. The melted poly then formed a ring on the outside of this hole
and I believe that this ring would be strong enough to prevent tear-out
(I did not try putting it under tension). Simple, neat, and the join,
once under tension, could be covered with the poly joining tape if a
belt and braces solution is required.

If/when my polytunnel next tears, I will definitely give this a try.


--
Howard Neil

Stefek Zaba wrote:
I used baler twine, which is a 3mm or so plastic string, which can easily
be melted into a nice point.
....with the aid of a welding torch. Thereby fulfilling the LAW, which
requires ALL agricultural repairs to be made using baler twine and a
welder...

I think I'll stick to baler twine only thank you, especially for when my
trousers fall down.

Owain

"Howard Neil" wrote in message
...



This may be a good time to ask local farmers for their used sheets.


I don't know farmers who use them and my garden plots are measured in low
single numbers of square yards, not hectares. And I only have four plots.


Ask your daughter to obtain some and collect it when you next visit?

She's, er, otherwise engaged at the moment. Pregnant.


I'll post the result if my experiments tomorrow.

How about you picking up a bit for me, I'll collect it in July?

Mary

Mary Fisher wrote:
"Howard Neil" wrote in message
...


This may be a good time to ask local farmers for their used sheets.


I don't know farmers who use them and my garden plots are measured in low
single numbers of square yards, not hectares. And I only have four plots.


Ask your daughter to obtain some and collect it when you next visit?


She's, er, otherwise engaged at the moment. Pregnant.

Congratulations, Granny. :-)


I'll post the result if my experiments tomorrow.


How about you picking up a bit for me, I'll collect it in July?

I've already had my neighbour's plastic (the only one I know who has a
silage clamp). The others all use silage bales. :-(

--
Howard Neil

In uk.d-i-y Howard Neil wrote:
Mary Fisher wrote:
"Howard Neil" wrote in message
...

Mary Fisher wrote:


You didn't specify "poking plastic" originally. Is that what you'd do?

Yes. I use the same principle in my veg patch. I cover it with old silage
sheet and make holes with a blow lamp. The sheet melts back to produce a
hard ring and a nice clean hole to plant the veg through.


Actually that's not a bad idea - for a veg patch. I might (albeit
reluctantly) follow your example :-)

This may be a good time to ask local farmers for their used sheets. They
should now have cleared their silage and they will have to pay to have
the sheets removed. Someone offering to take a sheet off their hands for
nothing will be welcomed.


However, I think that such holes might be too large for a polytunnel lacing
repair.

You haven't seen the size of the laces. :-)

The plastic in some areas is quite degraded.
The south-east corner has perhaps 1/3 the pull-through strength of
the north-west one.

"Howard Neil" wrote in message
...
Mary Fisher wrote:
"Howard Neil" wrote in message
...


This may be a good time to ask local farmers for their used sheets.


I don't know farmers who use them and my garden plots are measured in
low single numbers of square yards, not hectares. And I only have four
plots.


Ask your daughter to obtain some and collect it when you next visit?


She's, er, otherwise engaged at the moment. Pregnant.

Congratulations, Granny. :-)

Nothng to do with me.


I'll post the result if my experiments tomorrow.


How about you picking up a bit for me, I'll collect it in July?

I've already had my neighbour's plastic (the only one I know who has a
silage clamp). The others all use silage bales. :-(

So do daughter's neighbours.

Never mind, I'll have to leave empty handed:-)

Mary

--
Howard Neil

Ian Stirling wrote:

The plastic in some areas is quite degraded.
The south-east corner has perhaps 1/3 the pull-through strength of
the north-west one.


How about lacing in a new piece of poly? Mind you, that sounds a real
challenge to the system.

--
Howard Neil

In uk.d-i-y Howard Neil wrote:
Ian Stirling wrote:

The plastic in some areas is quite degraded.
The south-east corner has perhaps 1/3 the pull-through strength of
the north-west one.


How about lacing in a new piece of poly? Mind you, that sounds a real
challenge to the system.

I have a replacement cover, which is going to be put on at some point.
Replacing bits would be slight overkill.
However, on one end, it's probably going to get the old cover moved inside,
to form double glazing.

Ian Stirling wrote:
In uk.d-i-y Howard Neil wrote:

Ian Stirling wrote:


The plastic in some areas is quite degraded.
The south-east corner has perhaps 1/3 the pull-through strength of
the north-west one.


How about lacing in a new piece of poly? Mind you, that sounds a real
challenge to the system.


I have a replacement cover, which is going to be put on at some point.
Replacing bits would be slight overkill.
However, on one end, it's probably going to get the old cover moved inside,
to form double glazing.

That sounds good. If you could get some bubble wrap, you could perhaps
put it between the two layers of poly and improve the double glazing
effect still further.

--
Howard Neil

Howard Neil wrote:
You can buy a special tape for this. It is like a very strong
sellotape,
at least as strong as Duck tape but clear(ish).

They actually do make clear Duck Tape
http://www.laoffice.co.uk/Adhesives-...ear-568722.htm

In uk.d-i-y Howard Neil wrote:
Ian Stirling wrote:
In uk.d-i-y Howard Neil wrote:

Ian Stirling wrote:


The plastic in some areas is quite degraded.
The south-east corner has perhaps 1/3 the pull-through strength of
the north-west one.


How about lacing in a new piece of poly? Mind you, that sounds a real
challenge to the system.


I have a replacement cover, which is going to be put on at some point.
Replacing bits would be slight overkill.
However, on one end, it's probably going to get the old cover moved inside,
to form double glazing.

That sounds good. If you could get some bubble wrap, you could perhaps
put it between the two layers of poly and improve the double glazing
effect still further.

Bubblewrap is very, very UV degradable unfortunately.

Ian Stirling wrote:
In uk.d-i-y Howard Neil wrote:

That sounds good. If you could get some bubble wrap, you could perhaps
put it between the two layers of poly and improve the double glazing
effect still further.


Bubblewrap is very, very UV degradable unfortunately.

That's a shame. Back to the drawing board. :-(

--
Howard Neil