double sided carpet tape is also used in making cheap tyvek and polytarp
sails. I haven't used it myself but from what I've read on the Internet
its reinforced with glass fibre and is very strong. It might be ideal for
applying patches where tape alone won't do.

--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
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Keith wrote:
: ... and will pull apart with very little stress. Polyethylene is notorious
: for having a surface that nothing will stick to. You can heat weld it, but
: it's beyond most non-commercial applications. It takes specific heat,
: pressure and dwell times, done either by bar sealers or "doughboy"
: continuous band sealers. You can try any glue you want, but I can tell you
: from years in R&D in the plastics industry, there is nothing that will work
: well with PE. Best bet are those tapes mentioned earlier, used on both
: sides. Duct tape will for for a few weeks, but weather and UV will tear it
: up pretty fast. Really... those blue poly tarps cost what... $5-15? Replace
: it if it's gone!


It all it was, was a blue poly tarp I would just replace it.

But it is not. It's a 33 foot by 20 foot piece of 6 mil clear poly
that I use as a roof on my boat shelter. It works great as a
"greenhouse", and to be honest, I dont' feel like replacing it because
of one tear. But if I don't deal with the tear, it will get larger.

Gregg

How long has it been up? Regular 6 mil poly is not going to last more
than 6 months to a year in the sunlight. Any repairs on old sheets is
wasted effort. I suffered with it for a couple of years and then went
to real greenhouse film. It has been up for over 3 years now and is
still just as strong as new. It cost about 3 times as much as regular
builders 6 mil poly but it will last 4 or 5 times as long and you are
not faced with the hassles of replacing it.

Gregg Germain wrote:

It all it was, was a blue poly tarp I would just replace it.

But it is not. It's a 33 foot by 20 foot piece of 6 mil clear poly
that I use as a roof on my boat shelter. It works great as a
"greenhouse", and to be honest, I dont' feel like replacing it because
of one tear. But if I don't deal with the tear, it will get larger.

Gregg

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

I can't remember the brand name. That happened in Haiti 25 years ago and I
used some german contact cement that I had on the boat.
It worked relatively well but I remember that we had to press the glue line
down under a 2x4 then hit with a hammer . . . all fine sailmaking skills . .
..


--
Jacques
http://www.bateau.com


"Keith" wrote in message
...
... and will pull apart with very little stress. Polyethylene is notorious
for having a surface that nothing will stick to. You can heat weld it, but
it's beyond most non-commercial applications. It takes specific heat,
pressure and dwell times, done either by bar sealers or "doughboy"
continuous band sealers. You can try any glue you want, but I can tell you
from years in R&D in the plastics industry, there is nothing that will
work
well with PE. Best bet are those tapes mentioned earlier, used on both
sides. Duct tape will for for a few weeks, but weather and UV will tear it
up pretty fast. Really... those blue poly tarps cost what... $5-15?
Replace
it if it's gone!


"Dave Cannell" wrote in message
.. .
NO, contact cement is NOT rubber cement. Contact adhesive is contact
adhesive.

In article , William R. Watt wrote:
"Jacques Mertens" ) writes:
Many years I experimented with junk sails made from polytarp, the
blue
stuff, and contact cement worked fine.

"contact" cement is also called "rubber" cement

people who make polytarp sails also bond by heating with a hot iron.
never tried it myself.

--


--------------------------------------------------------------------------
----
William R Watt National Capital FreeNet Ottawa's free community
network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-freenet email must have "notspam" in subject or it's
returned

Glenn Ashmore wrote:
: How long has it been up?

1 month.


Regular 6 mil poly is not going to last more
: than 6 months to a year in the sunlight.

It's not like this is the first time I've done this:

I've gotten pretty good lifetimes out of this stuff in thw
past. This is because in the winter what sun we do get is low angle.

And in the summer, I cover the clear plastic with a white tarp to
reflect the sun off the shelter/boat. So the harsh summer sun is not a
factor in breakdown of the clear plastic tarp.

However, as I wrote in another note, the production qualityof this
stuff has fallen off severely. So I might be interested in a substitute.

:Any repairs on old sheets is
: wasted effort. I suffered with it for a couple of years and then went
: to real greenhouse film. It has been up for over 3 years now and is
: still just as strong as new. It cost about 3 times as much as regular
: builders 6 mil poly but it will last 4 or 5 times as long and you are
: not faced with the hassles of replacing it.

Ah ok I'm interested in this. Who sells it? Is "Greenhouse film" the
actual name? Shoudl I use that for a google search?

thanks!


--- Gregg
"Improvise, adapt, overcome."

Smithsonian Center for Astrophysics
Phone: (617) 496-1558

Do a search on "Greenhouse coverings".

What I used is Tufflite IV made by Tyco plastics. I got it from Parks
Seed but they are wholesale only. Search for Tufflite or AT Plastics
Dura-film. It is not cheap. 20' wide cut lengths of Tufflite are about
$2/foot and a 100' roll of Dura-film is about $150.00. Maybe someone
else here with a long term project will split a roll with you.

If it has only been up a month you may as well duct tape it closed and
wait until next year. Better yet is Poly-patch, a tape made for
patching poly greenhouse film. The patch will last longer than your
cover. Try B&T Growers supply. They have 2" wide rolls for about
$10.00. Thye also have Dura-film.

http://www.growersupply.com/polypatch.html

Gregg Germain wrote:
Glenn Ashmore wrote:
: How long has it been up?

1 month.



Regular 6 mil poly is not going to last more

: than 6 months to a year in the sunlight.

It's not like this is the first time I've done this:

I've gotten pretty good lifetimes out of this stuff in thw
past. This is because in the winter what sun we do get is low angle.

And in the summer, I cover the clear plastic with a white tarp to
reflect the sun off the shelter/boat. So the harsh summer sun is not a
factor in breakdown of the clear plastic tarp.

However, as I wrote in another note, the production qualityof this
stuff has fallen off severely. So I might be interested in a substitute.

:Any repairs on old sheets is
: wasted effort. I suffered with it for a couple of years and then went
: to real greenhouse film. It has been up for over 3 years now and is
: still just as strong as new. It cost about 3 times as much as regular
: builders 6 mil poly but it will last 4 or 5 times as long and you are
: not faced with the hassles of replacing it.

Ah ok I'm interested in this. Who sells it? Is "Greenhouse film" the
actual name? Shoudl I use that for a google search?

thanks!


--- Gregg
"Improvise, adapt, overcome."

Smithsonian Center for Astrophysics
Phone: (617) 496-1558


--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Gregg Germain wrote in message ...
Keith wrote:
: ... and will pull apart with very little stress. Polyethylene is notorious
: for having a surface that nothing will stick to. You can heat weld it, but
: it's beyond most non-commercial applications. It takes specific heat,
: pressure and dwell times, done either by bar sealers or "doughboy"
: continuous band sealers. You can try any glue you want, but I can tell you
: from years in R&D in the plastics industry, there is nothing that will work
: well with PE. Best bet are those tapes mentioned earlier, used on both
: sides. Duct tape will for for a few weeks, but weather and UV will tear it
: up pretty fast. Really... those blue poly tarps cost what... $5-15? Replace
: it if it's gone!


It all it was, was a blue poly tarp I would just replace it.

But it is not. It's a 33 foot by 20 foot piece of 6 mil clear poly
that I use as a roof on my boat shelter. It works great as a
"greenhouse", and to be honest, I dont' feel like replacing it because
of one tear. But if I don't deal with the tear, it will get larger.

Gregg


Try some weathershield clear tape available at Walmart, the stuff you
get in the winter insulation isle. It looks like packing tape, but it
is not the same, it is stretchy a little so it gives and holds real
nice. We use it to repair plastic weather sheeting all the time, it
holds up as long as the plastic if done properly. Put a layer on each
side of plastic, along the tear.
Scotty from SmallBoats.com

Yea, search for greenhouse film. Monsanto makes it, as do others. It uses a
nickle UV inhibitor that will give it a reasonably long life, as long as
it's installed properly. If the clear plastic has a greenish tint to it, it
has nickle UV inhibitors in it. If it's clear, it doesn't. Regular poly has
no uv inhibitors, and will crack up in less than a year, especially clear.
The best UV inhibitor BTW is carbon black, so black plastic will last the
longest. White plastic will cut down on the transmission of UV to whatever
is underneath it, but will still allow some. The pigment is titanium
dioxide.

"Gregg Germain" wrote in message
...
Glenn Ashmore wrote:
: How long has it been up?

1 month.


Regular 6 mil poly is not going to last more
: than 6 months to a year in the sunlight.

It's not like this is the first time I've done this:

I've gotten pretty good lifetimes out of this stuff in thw
past. This is because in the winter what sun we do get is low angle.

And in the summer, I cover the clear plastic with a white tarp to
reflect the sun off the shelter/boat. So the harsh summer sun is not a
factor in breakdown of the clear plastic tarp.

However, as I wrote in another note, the production qualityof this
stuff has fallen off severely. So I might be interested in a substitute.

:Any repairs on old sheets is
: wasted effort. I suffered with it for a couple of years and then went
: to real greenhouse film. It has been up for over 3 years now and is
: still just as strong as new. It cost about 3 times as much as regular
: builders 6 mil poly but it will last 4 or 5 times as long and you are
: not faced with the hassles of replacing it.

Ah ok I'm interested in this. Who sells it? Is "Greenhouse film" the
actual name? Shoudl I use that for a google search?

thanks!


--- Gregg
"Improvise, adapt, overcome."

Smithsonian Center for Astrophysics
Phone: (617) 496-1558

Well no need to worry about repairing rips inthe tarp - this weekend's
Nor'easter took car of the cover.

So now I have to get more plastic. There's the Greenhouse film, but
that seem slimited to 6 mil. I was wondering if there was another
source of clear poly plastic that's thicker than 6 mil.

Jamestown also sells clear ploy with a weave in it to resist tears. I
might try that.



--


--- Gregg
"Improvise, adapt, overcome."

Smithsonian Center for Astrophysics
Phone: (617) 496-1558

Black will last a lot longer, if the heat isn't a problem. That clear woven
stuff will be OK for a few months, but will still degrade in the sunlight.

"Gregg Germain" wrote in message
...
Well no need to worry about repairing rips inthe tarp - this weekend's
Nor'easter took car of the cover.

So now I have to get more plastic. There's the Greenhouse film, but
that seem slimited to 6 mil. I was wondering if there was another
source of clear poly plastic that's thicker than 6 mil.

Jamestown also sells clear ploy with a weave in it to resist tears. I
might try that.



--


--- Gregg
"Improvise, adapt, overcome."

Smithsonian Center for Astrophysics
Phone: (617) 496-1558