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rearview_mirror.jpg

Awhile back, I wrote about co-opting the awesome glue used to mount rear-view mirrors for hobby projects. An interested reader e-mailed me a couple weeks later asking if I knew how to remove a rear-view mirror button from a windshield, which I didn’t. Several people have reported that trying to forcibly remove the metal button can actually break a divot of glass out of the windshield. I was therefore not optimistic, but we talked a little about the idea of using an organic solvent combined with sharp lateral pressure parallel to the glass. She experimented a bit, and, what do you know, eventually succeeded! Here’s her report:

We had some paint stripper in the house (BIX brand – not sure what is in it). I tried dipping a small artist’s brush into it, and then painting it all around the edges of the button (protecting my dashboard with some scrap cardboard). I left it for a while, then tried “whacking” the button using a metal-bladed putty knife as close to the plane of the windshield as I could get it, tapping it on the handle end with a hammer.

No luck. I tried the procedure again – still no luck.

Then I decided to try acetone. I soaked a cotton wad with regular acetone-based nail polish remover (which is what I had), and applied it all around the button edges. First try at whacking – no luck. Than I applied more remover, tried whacking again, and voila – the button popped off, and no harm done to the windshield!

Ambient temperature was about 75 degrees. I was going to try heating the button with a hair dryer if necessary, but it turned out I didn’t have to.

[Thanks, Zee!]

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.


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Comments

  1. netmaster says:

    Try using a torch and vise grips, no whacking needed. Any propane or butane torch should work. I recommend vice grips so you don’t accidentally drop the heated button once it is removed. Clamp the vise grips to the button but don’t apply any pushing or pulling force. Heat the button by aiming the low flame at the middle of the button while applying a rotational force with vice grips, no pulling or pushing. Heat it in 5 second on 5 second off increments to let the heat transfer to the glue side. After about 20-40 seconds the glue will soften and the button will twist off with very little effort. Remove the remaining glue with a razor and acetone. Don’t use this method on a cold windshield.

  2. g7kse says:

    Rear view mirror bonder (as its called in the UK) is a structural anaerobic adhesive from the same family of adhesives as threadlocks and bearing retainers (loctite). It cures to a thermoset plastic which is very strong in shear. Poor in peel. The little mesh is part activator (copper salt based product – or at least it was a while back when I worked with these things) and part buffer between the glass and metal.

    If you bond the metal directly to theglass it’s likely to shatter the glass as temperture (and expansion / contraction) occurs.

    Acetone might loosen not so good bond lines and heat in excess of 120C will weaken the bond. But there is no sure fire way of getting it off. Its not supposed to come off! Please be careful as you’re just as likely to crack the glass, or get a fuzzed head from acetone or worse still blow yourself up with a blowtorch and acetone.

  3. craig says:

    Why would one want to remove the rearview mirror and bracket? Since it’s illegal to operate a motor vehicle without one, you may as well disconnect the turn signal flashers while you’re at it.

  4. netmaster says:

    @craig
    I removed a few for customers who, when trying to replace a mirror that had fallen off, glued the button on upside down or in the wrong spot. I have also removed them from cargo vans that have equipment inside blocking the rear window. A rear view mirror serves no purpose if there isn’t a rear view. Stock mirrors also get in the way of these racing type mirrors http://www.fennelfamily.com/gti-vr6/body_interior/inst_wink_panoramic_mirror.html.

    @g7kse
    Good info about the details of the adhesion technology, but I beg to differ with your glum assessment that there is no sure fire way to break the bond. The heat method has worked every time I’ve used it with no cracked windshields. And, to be clear, I said to use the acetone *after* the button was removed to clean up the remaining glue.

  5. drewski_brewski says:

    I guess I should have mentioned the acetone in my diatribe on the original post. Next time, I’ll quote less Red Green, and more technical info.

  6. g7kse says:

    Didn’t mean to sound glum. I used to answer irate consumers when I worked with this stuff (A benfit of being the most junior in the office at the time)and a lot of people tried to take off the metal button on the windscreen and pulling a nice pyramid of glass out. Almost all of them were Fords. That was in 1995 though!

    You’d be surprised how many people want a glue thats really strong but easy to take off :-)

  7. Lee says:

    Tried the acetone, no go, borrowed the wife’s blow dyer and a pair of vice grips. Heated the outside on the rearview mirror button and off it came. (about 15-20 seconds of heat)

  8. Gary says:

    THANK YOU! The butane torch worked like a charm .. was a little nervous about glass expansion but after about 45 seconds using the 5 seconds on 5 seconds off it practically fell off.

  9. Rob says:

    Might be a dumb question but are the “buttons” all a standard size or do they vary from carmaker to carmaker?

  10. dp says:

    I used the acetone and blower dryer method. I took a syringe with finger nail polish remover and drippled it down the windshield where the mount was so it would run behind it. I let it set for an hour or so and then used a blow dryer to heat the mount. Took about 5 mins and it twisted right off with a pair of channel locks. Thanks for the great info. My windshield thanks you :)

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