3M window weld and Cure Time

[Eric Seppanen]

On Fri, Jun 14, 2002 at 08:41:11AM -0500, Ben Davis wrote:
> Use 94 shore urethane from McMaster-Carr instead. It sets MUCH faster than
> 3M window weld, and, from my experience, works better than the 3M weld. Just
> go to www.mcmaster.com , type in part number 8644K18, and order it. You will
> need to use duct tape or plastc wrap on one side of your mounts because this
> stuff pours. Just mix up the two ingredients and pour. They will be ready to
> install the next morning. The 3M stuff (with no ovening) takes many days to
> full harden.

If you read the directions on the stuff from Mcmaster-carr, it says the
stuff takes several days to fully cure (though it may be hard enough to
work after 24-48 hours).  Pouring mounts is enough of a pain that I
wouldn't risk wrecking them by cutting corners on the cure time.

I used 80 shore A urethane, which is softer than 94 shore A, and my mounts
were really, really firm.  Dashboard, hood, trunklid... everything
vibrated.  I'm curious how 94 shore A is even livable-- have the fillings
rattled out of your teeth yet?

Mcmaster-Carr sells the same stuff in three hardnesses:
60 shore A   p/n 8644K24  (softest)
80 shore A   p/n 8644K11
94 shore A   p/n 8644K18  (hardest)

they also sell a different material called "FDA flexible urethane" that
is sold in more hardnesses.

Note that there are different scales when referring to hardness
(durometer): "shore A", "shore D", "shore 00", "rockwell"...  80 shore D
is way, way, harder than 80 shore A.  In the mcmaster-carr catalog, 60
shore A is described as the hardness of "tire tread".  A bowling ball is
just past 100 shore A... that's why I think 94 shore A is inappropriate
for motor mounts.