Epoxy (was: RE: (ET) Mower motor flange problem)

["Chris Tromley" <chris_t microtrac com>]

Larry Elie wrote:

> BTW, epoxy does 
> NOT work; been there/done that.

Hi Larry,

Epoxy does not work in all situations, but it can be very effective in a
surprising number of situations if used properly.  I've used JB Weld to
do some pretty amazing things.

The key is to use the epoxy as it was meant to be used.  That's not
meant to be condescending - joint design is a rather subtle thing.  Many
people get poor results because they expect the epoxy to be strong as a
material in and of itself.  It's not.  It's only plastic.  Good joint
design uses epoxy's ability to bond one material to another over a large
area.  In most cases the key to success is to use an additional piece of
metal that provides strength, bonding it to the broken equipment.

For example:  No one would expect a crack in the sheet metal of a mower
deck to be fixed by troweling epoxy over the crack.  But if you add a
strip of sheet metal of the same thickness, bonding it to the deck over
the crack, it should last quite well.  The added strip is providing the
structural strength, the epoxy holding the pieces together.  Both are
doing what they do well.

If part of a mower motor flange breaks off (haven't looked at one, I'm
guessing here), just gluing the broken piece back on will probably not
work.  You don't have much surface area for the epoxy, and you're
loading it in a way it's not suited for.  But if you have a
flange-shaped backer and bond it over the original flange, the backer
carries the load.  It'll last fine.

My experience is with JB Weld, an epoxy made specifically for bonding
metals.  It's available at most hardware and auto parts stores.  I
*always* have some on hand.  It's not necessarily a preferred repair,
but there are times when welding or bolting won't cut it either (like
trying not to fry your motor magnets).  Scarf up the surface, make sure
the pieces are clean, works great.

No connection with the manufacturer, other than being a happy user.

HTH,
Chris