The Windshield & Rearview Mirror Saga

My son through a baseball in the car knocking the rearview
mirror off the windshield.

Now get this... The adhesive between the baseplate and the
windshield did not fail; the glass did.

To be accurate, 2/3 of the adhesive between the baseplate
and the windshield did fail, but 1/3 did not resulting in a
dime-size piece of windshield still attached to the baseplate.

I assume the best adhesive to re-attach the baseplate-to-
windshield surface is still rearview mirror adhesive, but what
is the best adhesive to re-attach the glass-to-glass surface?

Thanks!

Joe Colella

 

Try "threw."

Uh...try moving the base plate up or down to avoid the chip? Permatex
mirror adhesive works well as long as you prep the glass as per
directions with 94% isopropyl alcohol, available at most pharmacies.
Don't just "Windex" the glass, as it does leave deposits, as does 70%
"rubbing" alcohol. Properly prepped, I've never had Permatex adhesive
fail on these repairs.

 

My experience was that a Las Cruces summer would cause it to fail; I
was putting it back on annually. JB Weld fixed it permanently.

I don't know where DesertBob is... if he's somewhere hotter than here
then I wasn't prepping it as well as I thought I was; if he's
somewhere cooler, then the Permatex adhesive doesn't stand up to
extreme heat.

 

Really, PERMATEX works on glass-to-glass as well as metal-to-glass?

 

JB Weld for metal-to-glass and glass-to-glass...

That's good to know!

Thanks,

Joe

 

Of course, be aware that it *isn't* transparent.

 

Been to Las Cruces...mild there!

Edge of the Mojave Desert.

115° here isn't uncommon, and the 2500 ft elevation provides excessive
UV year 'round.

If you used "rubbing alcohol" to prep the glass, that was your
undoing. "Rubbing alcohol" contains 5% glycerine by volume and is
unsuitable for industrial/mechanical cleaning purposes. It also
contains 25% water by volume.

 

Permatex REAR VIEW MIRROR ADHESIVE, yes. Permatex RTV or #2, no way.

Another Permatex product that works, but it a bit fragile: Rear
window defogger repair goop.

 

Thanks!

 

.... perhaps this was intuitively obvious to a PhD, but certainly not a
schmuck like me!

 

Bear in mind that the PhD is climatologically challenged, as well. So
much for a "renaissance education!"

The Permatex Mirror Mount Adhesive is "transparent," but the object of
the game, of course, is to only have the adhesive between the mounting
flange and the glass...nowhere else.

 

Good points!

 

Well... I didn't know how familiar you were with JB Weld, and your
"glass-to-glass" comment sounded like you might want to use it in an
application other than just this particular repair. So mentioning
that it isn't transparent seemed prudent.

I also don't know what DesertBob means by climatologically challenged.
With certain glaring exceptions like the past month, Las Cruces's
climate is nearly perfect. Maybe a little warmer than I'd like in the
summer (but not in the same league as Phoenix or Houston, for
example), but no snow in the winter and (ordinarily) no damned rain.
This Seattle native really, really appreciates that last point.

 

Dr. Joe,

My "intuitively obvious" comment was meant appreciatively, although
delivered sarcastically and disrespectfully.

Please accept my apologies.

Joe

 

You didnt' seem to think that I really did live in a "desert," and I
assure you that I do!

Las Cruces has a very dry desert climate, making summer cooling via
adiabatic means a snap. We enjoy that same benefit, although are
foiled when monsoonal flow from Mexico messed things up. As I
remember it, it's a very nice town all around...certainly a bit more
likable than Alamogordo to the north!

Seattle's a great city as well as it Portland, but that constant
parade of Pacific storms anytime other than in summer is enough to
drive one to the antidepressants.

 

So you're a little hotter than here (105 is common, 115 is uncommon
but not unheard of),
and we're a little higher than you (4000 ft). Don't know which
difference is more significant.

Looking around a bit, it looks like the amount of water varies by
brand; I haven't found a brand that admits to having any glycerine in
it, though about the only thing various brands of rubbing alcohol seem
to have in common is that they have some amount of isopropyl alcohol.
Frankly, it's been enough years since I last had to put the mirror
back on that I don't remember what I used to clean it with... rubbing
alcohol is a possibility.