Repairing poly-tunnels.

[Ian Stirling]

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.

[Mike]

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

[Mary Fisher]

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 Lyle]

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.)

[Mary Fisher]

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

Looks awful though!

Mary

[Howard Neil]

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.

[Mary Fisher]

"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.

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]

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.

I certainly like the sound of it.

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

[Bob Mannix]

After the mice ate my tent :o( 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.

[doozer]

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?

[Mary Fisher]

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

[Toolmaker]

"doozer" wrote

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

[Howard Neil]

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.

[Peter Stockdale]

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

[Mike Lyle]

product

there

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.

[Peter Stockdale]

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

[Mary Fisher]

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

[Mike Lyle]

such-like,

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.

[Howard Neil]

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.

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

I'll post the result if my experiments tomorrow.

[Ian Stirling]

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.