Hi Roy, you seem to be the man with the know how!
Here is a link to a picture of what I am trying to accomplish.
http://funjax.com/pondhole
My plan is to cut a hole in the other pond and to glue EPDM to the inside of
each pond.
The hole at the lip is about 10" across.
Please take a look at picture and tell me how you would proceed.
Thanks for your help!, Larry



"Roy" wrote in message
...
solvent based cements / adhesives do little to adhere sufficiently to
PE or PP type plastics........

Short of welding with a hot air welder, it is best to scrap a layer
or so of the original surface off with a scraper (get rid of any
surface oxidation) pass a neutral flame (from hand held propane
torch) along and around the surface you intend to bond to, scuff wioth
sandpaper....then apply your adhesive of choice.......believe it or
not, these plastics oxidize fairly rapid in normal atmosphere
environments, and can oxidize within hours even as a new item right
out of the mold.......so ts important to remove oxidation before
glueing it up. Also by passing a flame over a preforms surface prior
to bonding, it changes the surface of the materials molecular
structure which aids in making a good bond.


I have found a special adhesive that is made specifically for plastics
typically found in preformed products.........but its really pricey,
and you have to buy a factory kit of the stuff which consists of 12
packets of adhesive. Until you buy this adhesive and considering the
small quanity in each packet, it would be cheaper to replace the
liner. Its big time $$$

The standard 3M 4200/5200 adhesives do not hold sufficiently without
further use of mechanical fasteners, but they will make a suitable
joint when used with fasteners.

Scotch-Weld DP-190, which is expensive. The 1.7 OZ packets are only
about $14 each, but these packets also require a proper applicator tip
for each use.......and minimum package of this adhesive is 12 packets,
so it is kind of pricey, but it works.........

Lord Corporation's 7540-AB urethane adhesive will also work, but it to
is pretty pricey and may be a bit harder to find. It is packed in 50
ml packets and costs perhaps $10 per packet, but once again minimum
package is 12 packets..........

There is a product made that will allow you to stick teflon to teflon
and its reported to work with PP or PE and most all other hard to
stick materials.......but I don;t know if it would be suitable for use
with fish or not. It smells like mothballs for about a month after its
applied, and carries a hazmat charge. and comes in 1 qt. containers
at $109 a qt...........This stuff etches the surfaces, to the point
that most any adhesive will stick, such as regular old contact
cements.

I think your best solution to adhering a liner to a preform would be
to use regular old RTV silicone product, in conjunction with a strip
of like preform material to make a scab patch and use mechanical
fasteners to prevent any possible lifting or shear of the applied
joint. Sandwhich the liner between the preform and the scab patch with
RTV between each and every piece after de-oxidizing the surfaces
(scraping, flame treatment and sandpaper)do not use any chemical type
cleaners after deoxidizing, apply RTV and clamp up and then install
some stainless steel fasteners with flat washers or finishing washers
to secure it. Coat the fasteners threads with RTV as well. YOu should
wind up with a good strong water proof connection that will not lift
or peel or shear and make a leak.
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