Re: [DML] Re: 3M VHB Tape on Rear-View Mirror?

[Joe Angell <jangell@xxxxxxxxxxxxxxxxx>]

I just did this recently myself with a compass/temp/map light/auto- 
dimming mirror due to a windshield replacement, using ideas that I  
found after reading posts the posts here (it sounds like they were  
your ideas, actually :) ).  Previously, it had been carefully glued  
on at a vendor with my permission, and it worked, but I wasn't  
willing to try that again by myself.

I used a thin strip of clear plexiglass and moulding tape (which I  
believe is basically VHB).  I cut a strip of plexi with a utility  
knife, and then just rounded the corners and beveled the edges a  
little with sand paper.  I didn't do any bending of the strip or  
anything like that; I didn't notice much curve in the windshield at  
all, but maybe I used thinner plexi that could more easily match the  
contours of the glass.  I also made the strip longer so that it  
stretched a couple inches below the black square on the windshield,  
which let me mount the larger mirror so that it wouldn't hit the  
headliner.  My piece of plexi goes from an inch or two below the  
black square all the way up to very top of the windshield behind the  
headliner.

The tape holds the plexiglass onto the windshield very well.  I don't  
think I'm ever getting it off again.  The tape is grey, but it  
doesn't look too out of place to me.

I tried four times to use mirror adhesive to glue the mirror button  
on, but each time it fell off.  I scratched the glue off the button  
and roughed up both surfaces with sandpaper each time I tried.  I  
almost just ran a screw through the button.  I finally just used a  
five minute epoxy, plus I braced a piece of wood wedge between the  
shifter and the button to provide constant force while the epoxy  
cured.  In retrospect, I should have glued the button on before I  
taped the plexi to the windshield so I could let gravity and some  
books keep constant pressure on the button, but this seemed to work  
fine.

It's been a few days now and it hasn't fallen off, so I think I'm  
good. :)


Also, there was something else I toyed with, but didn't actually  
try.  Since the issue is the thermal expansion difference between the  
metal button and the glass, I was wondering if you could cut a small  
piece of plastic that was the shape of the button, glue that to the  
window, and glue the button to that.  The reason you can't just use  
tape that is the size of the button is due to the low surface area,  
and you can't use glue because of the metal expansion, but it seems  
like a glass-glue-plastic-glue-metal sandwich might be sufficient to  
dampen the effects of the expanding metal by the time it gets to the  
windshield.  It seems unlikely to me that we need to worry about the  
glue itself expanding at a different rate.  If this theory is  
correct, then this would result in a nearly factory appearance to the  
mirror install.  I didn't feel like cracking the windshield I just  
replaced if I was wrong, though.

Now back to figuring out how to get those center console A/C vents  
back on that rubber cowling...

-- Joe

> Been there.  Its quite a task.  You can't use the adhesive or you will
> bust your windshield, and the standard mounting tapes from the vendors
> are too weak for the job.  Its hard to find something that won't  
> damage
> the car, doesn't allow the Mirror to vibrate, won't drop of when you
> take a turn or park the sun for the day in the summer sun, and looks
> good.  The good news is, I've done it.  I did this about 18 months ago
> and have had zero problems since.
>
> So to mount the mirror you first need to create a new intermediate
> baseplate out of plastic.  I used smoke plex. Black Sintra will likely
> work even better.  I cut a strip approx. 1.5" wide (same width as the
> base of the mirror) by 9.5" long - the distance from the top of the
> windshield to the bottom of the mirror base, when it is its final
> position.
>
> ...
>




To address comments privately to the moderating team, please address:
moderators@xxxxxxxxxxx

For more info on the list, tech articles, cars for sale see www.dmcnews.com

To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/dmcnews/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/dmcnews/join
    (Yahoo! ID required)

<*> To change settings via email:
    mailto:dmcnews-digest@xxxxxxxxxxxxxxx 
    mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    dmcnews-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/