In article ,
(Simon Avery) wrote:

"John Arruda" wrote:

Hello John

JA I am currently building a pond (still digging). I have large
JA boulders that go 2 ft below water and come 4 ft out of the
JA water. Theyre about 10 ton or so. I would like to have the
JA liner below the water line and glue it or silicone it to the
JA large boulders making it waterproof. I really dont want to
JA show the liner above the water and stacking stones on the
JA liner and boulder would be very difficult since it's almost
JA vertical. Has anyone come across this dilemma?? I see many
JA pond pictures on the internet with similar setups but they
JA dont tell how the liner is hidden.

Ick. I'm pretty sure that your bond will be very hard to do. Maybe,
just maybe, hot tar painted around the granite in a 10" or so strip
would allow you to adhere the butyl to, but any movement in the liner
(and they do move) is going to push that joint very hard.

Other such effects, I think, are done by fitting the boulder after
it's been lined, or using clay puddling which will make a fairly good
seal as it expands. Concrete is a bugger to seal to stones
effectively, though it can be done; but not well enough to trust
completely. (Use PVA in the mix, pva on the granite, two coats of pva
once concrete has set, and then brush all over with cement slurry
(also with pva). I've done this and it works, but only in small
ponds.)

--
Simon Avery, Dartmoor, UK ? http://www.digdilem.org/


This is a true story. When I was a young boy, my family was living in
Wenatchee, WA in 1950 while my step-father was working as a construction
worker enlarging and rebuilding Rocky Reach dam on the Columbia River.

One evening he came home and said the Corps of Engineers had contracted
with river tugs to pull a succession of barges loaded with horse manure
to a position upstream of the dam. The horse manure was being shoveled
into the river, to disperse in the current and lodge against the
upstream face of the dam.

This particular dam is built of concrete spanning several natural rock
outcroppings, rock "islands" in the Columbia, for which a small
neighboring town was named (Rock Island, WA). Apparently there was a
problem with leakage between the concrete portions of the dam, and the
rock formations.

According to stepdad, as it was explained to him, horse manure contains
a high percentage of undigested fiber (as any country boy who has kicked
well-aged "horse biscuits" around the meadow knows) and this coarse
fiber would flow with the water into the leaks, lodge there and swell,
creating an effective natural seal.

Not that I'm suggesting this as a method for sealing between the liner
and the boulders, but then again, if some sort of "belt" could be fitted
to hold the butyl liner tightly to the boulder, then a good sealing
material between the liner and the rock might serve a good purpose.

Pass the biscuits?

Allen