Interesting Rich..
I didn't think of the antioxidant compounds, figuring the roofing liner
would be covered by shingles, providing some level of protection, once the
shingles seal in....
I was trying to establish if they added any low level herbicides, which I
have heard from various contractors that some roofing liners have.
I could not get an answer to that, other than he acknowledged some do...
Again, thanks for the wonderful hospitality you and Donna shared with us
while we were in Va!
I am going to send you the pics I promised, once I get caught up.
Had a series of problems (some major) when I got home..
Should have known Murphy hits whenever I leave for even a short vacation!
1 of the 6 left to resolve, then I can start playing again.
The 8 koi look very happy with their new home, and the electric fencing has
done the trick with the mink.. at least so far.
Greg

--


"RichToyBox" wrote in message
newste1b.170569$Oz4.43694@rwcrnsc54...

"Gregory Young" wrote in message
...
Hi all:
The bottom line, according to Firestone, there is a "decided difference"
between the 2 liners:
The MSD sheets may look similar, according to Firestone, but they are
not.
In fact he said to be sure to notice that under the product
identification
section, the chemical name descriptor, PondGard is listed as "cured
rubber
material", with no similar reference in their roofing line MSD sheet.
Why?

All rubber products have to be cured, (vulcanized), but the method of cure
may be different. Some of the rubber products are cured by microwave,
some
by brine solution, some by heated form, but the heat has to be there for
some time for the molecules to chemically bond, to give the properties
desired, such as tensile strength, hardness, elongation.

2) Their roofing liner has "additional processing", which "adds certain
chemicals useful to extend the life of the material". He would not
identify
the specific agents added, except to agree with me that "some" companies
add
plant inhibiting compounds to their roofing liner.

I suspect the additional chemicals used in the roofing liner, that would
not
be needed in pond liner is antioxidants. The roofing would be subject to
ozone in the atmosphere, that the pond would not be subjected to. I have
seen oils and waxes used as antioxidants, and both will migrate to the
surface of the rubber sample during ozone testing. If insufficient
amounts
are present, the rubber cracks like old tires on a parked car. Whether
these would be toxic or not, I don't know.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html



.
Happy ponding,
Greg