Re: [Paddlewise] glue for minicell/polyethylene

At 06:15 PM 7/9/99 +0000, Mark Zen wrote:
>i think this is another good test for Steve Jernigan ;-)
>
>At 09:42 7/10/99 +1000,  Peter Osman <PeterO_at_ambri.com.au> wrote:
>>Dave Kruger wrote
>>>That would be MEK:  methyl ethyl ketone.  Lacquer thinner should work just
>>>as well.
>>
>>Don't know if its been suggested yet but I was told that the glue used by
>>plumbers for PVC pipe should work on polythene - haven't tried it myself -
>>probably wise to try it on scrap polythene first.

Hi Mark et al!
	Well, I was just re-routing some acid waste lines the other day, now
where'd I put the cement . . .
	Hmmmm! Contains Tetrahydrofuran, MEK, Cyclohexanone, PVC. Pretty toxic.
I really think this stuff works by softening the surface of the PVC pipe /
socket which then become as one once the solvents evaporate, but here goes
nothing. A dab here, a dab there, slap 'em together . . .
Now if this had been two slabs of PVC rather than a couple of Nalgene
squirt bottles they would now be inseparable, but the nalgene isn't even
getting sticky. Lets try a little clamping action . . .
	Later. The cement has dried and left a film which can be peeled off
easily, and resembles plastic-wrap (figures; PVC in the cement). Didn't
even touch the Nalgene bottles, and the strength of the bond between the
surfaces is about what it takes to peel off the film; practically nil. I'm
not even gonna bother roughing up the surfaces on this one.
	Now I can hear you saying "But wait! 'Em are Nalgene bottles what are
designed to be resistant to various and sundry chemicals, not plastic
boats!", and you are quite correct. In anticipation of this I tried the
experiment using a bit of poly welding rod with the same results.
Polyethylene be tough stuff; you guys sure that's what those boats are made
of? The chemical compatibility chart in my Fluoroware catalog, under HDPE
(high density polyethylene) sez "NO" to concentrated sulfuric acid, fuming
nitric acid, toluene, isooctane, aniline, tetrahydrofuran, acetone,
benzaldehyde, cyclohexane, MEK, methylene chloride, perchloroethylene, TCE,
and carbon tetrachloride. Now some of these are in the PVC cement, and we
have already seen how little that affected the poly. Neither did the
acetone, xylene, or TCE I had available, at least not with any vigor. In
fact, I can't recall ever seeing anything get after poly in a hurry,
although I have seen nitric acid cause it to turn brown and brittle over
time. We use some poly sinks, but those are welded rather than glued. Have
to pass that question on to Dave K. Dave, do you know of any aggressive
solvent for polyethylene?
	Another thought; (I can see you cringing now!) perhaps a solvent in
conjunction with heating the surface to nearly the flow temperature of the
plastic? Or why not bypass the entire problem and use an aluminum pop-rivet
or two? Here then is another consideration, however trivial, for the
plastic vs composite argument: I don't have any problems at all getting
glue to stick to my kevlar hulls :-)
	 Oh well, enough amateur chemistry for today; my office stinks, and one of
our researchers just managed to melt the e-beam evaporation source. Sigh.
Looks like it's gonna be "one of those days"
ByeBye! S.
***************************************************************************
PaddleWise Paddling Mailing List
Submissions:     paddlewise_at_lists.intelenet.net
Subscriptions:   paddlewise-request_at_lists.intelenet.net
Website:         http://www.paddlewise.net/
***************************************************************************