Re: Joining PE (was:Tank Cap Seal Failure)

There are a variety of ways to get adhesives or paint to stick to
Polyethylene (PE). One is to run a small spark spray device over it (nahh,
we would have any of those around, would we?) which creates tiny pinholes
in the surface which provide a mechanical roughness that the adhesive or
paint can "key" into (since it doesn't stick, in the conventional sense).

Another is to use epoxy and prep it with Chromic Acid before. A recipe for
doing so can be found at http://home.earthlink-dot-net/~jimlux/hv/epoxprep.htm
, which I got from "the Bell Jar".

The best way is to weld it. You can get a plastic welding "torch"
(essentially a hot air gun with very low flow) that does a very nice job
with about 15 minutes of practice.  I suspect that you could modify a big
(50W) soldering iron to do the same, although the real thing works very
very well.  I've welded up oil tight PE boxes from 1/8" sheet, etc.

All it takes (hah) is a steady hand and a feel for when the plastic starts
to go soft and sticky (I'm told by my steel welding friends that it is much
like welding steel, although I'm much better at plastic than steel,
probably because there aren't all those sparks and you can see what you are

> Tesla List wrote:
> > 
> > Original Poster: David Trimmell <davidt-at-pond-dot-net>
> > 
> > Yes, Nothing Sticks to PP or PE (if someone knows of something let me
> > know!). 
> You can use Locktite Type 770 (RS #143-7116) To prime the surfaces of PP
> and PE, prior to glueing it together with Cyano-acrylate glue (10
> seconds glue) like Locktite type 401 and the like.
> Not a very strong bond, as would be suspected with cyano-glues, but
> quite usefull !
> Cheers, Finn Hammmer