Why stick mirrors to the windscreen? - Mookfish
Why do car makers stick the rear veiw mirror to the windscreen on modern cars?

It fell off for the third time this morning (just as i was changing gear so it bashed my hand.) First time it fell off was about an hour after buying the car, stuck back on with the pads you buy from halfords, that held for a few weeks, then it came off again, this time when dipping the mirror. Stuck it on with superglue as I happened to have it in the car. Now its fallen off again, any sugestions on how to make sure it stays on this time?

Older cars that I've owned had the mirror fixed to the roof and never had any trouble, why don't they do this on modern cars?
Why stick mirrors to the windscreen? - Chicken Vindaloo
Cost I would imagine.
Why stick mirrors to the windscreen? - barchettaman
In my experience, once they´ve fallen off once, they never get permanently stuck back on!
Why stick mirrors to the windscreen? - Mookfish
In my experience, once they´ve fallen off once, they never get
permanently stuck back on!


If it keeps falling off I might replace it with one of those suction ones that driving instructors use, can you get dipping ones I wonder.
Why stick mirrors to the windscreen? - daveyjp
Take a visit to your local windscreen repair centre. They use a glue system involving heat which is far better than those useless pads and in my experience they don't fall off again.
Why stick mirrors to the windscreen? - Mookfish
Thanks, will see about that next time SWMBO needs a lift to the wholesalers next to autoglass, I usualy end up sitting in the car bored for half an hour anyway.
Why stick mirrors to the windscreen? - Robin Reliant
I believe mirrors are stuck onto the windscreen for safety reasons, so that they will come off on impact should you get thrown against the screen. Older cars used to have them screwed to the top.
--
Robin Reliant, formerly known as Tom Shaw
Why stick mirrors to the windscreen? - Mookfish
So its a saftey feature for people who don't wear seat belts?
Why stick mirrors to the windscreen? - Adam {P}
Or for people who's seatbelts fail!
Why stick mirrors to the windscreen? - Mookfish
Or for people who's seatbelts fail!

Okay, I never though of that, and I supose if you were leaning accross to reach a child in the back at the other side your seatbelt wouldn't do much good either.
Why stick mirrors to the windscreen? - Red Baron
I think that they are stuck onto the windscreen because of the design of modern cars. The windscreen rakes far back into the roofline to the extent that mounting the mirror to the roof would require the user to crane his/her neck back too far so as to be uncomfortable. And yes, at that point they would become a serious safety issue in the event of a crash.

Superglue and epoxy won't work as there is a thermal mismatch between these and the windscreen glass. I've had the windscreen on my Alfa replaced three times and whatever sticky pads that the windscreen guys use have worked so far. There may be dirt/grease/grime that is preventing yours from adhereing properly. Try using alcohol to clean the surfaces first.
Why stick mirrors to the windscreen? - henry k
Take a visit to your local windscreen repair centre.
They use a glue system involving heat which is far better than those useless pads and in my experience they don't fall off again.

>>
>>
Well, I visited my local windscreen repair centre.
They kindly gave me two sticky pads, from a big roll of them, and would not accept any payment.
So they obviously use them
I cleaned the screen and the mirror arm before refitting. The mirror is still in place two years later.

So I am happy with those "useless" pads but suspect that clean surfaces are required to ensure a good bond.

As has been stated on a previous thread do NOT use superglue.

Why stick mirrors to the windscreen? - Mookfish
As has been stated on a previous thread do NOT use
superglue.

Why not? Does it do something terrible to the screen?
Why stick mirrors to the windscreen? - Altea Ego
No it just dont work for this application, The pad is required as it allows the thermal expansion to take place.
------------------------------
TourVanMan TM < Ex RF >
Why stick mirrors to the windscreen? - Mookfish
Oh good, do NOT use superglue, the capitals got me worried for a moment.
Why stick mirrors to the windscreen? - Robin Reliant
NEVER use superglue on anything, unless you want to walk round with your lip stuck to your earlobe.
--
Robin Reliant, formerly known as Tom Shaw
Why stick mirrors to the windscreen? - Altea Ego
NEVER use superglue on anything, unless you want to walk round
with your lip stuck to your earlobe.


wow wou tewl mwe, wits a bwit wate wow
------------------------------
TourVanMan TM < Ex RF >
Why stick mirrors to the windscreen? - barchettaman
Once got a blob on my eyelid.
Hand went to eyelid, stuck to eye and cheek, eyelids/lashes stuck together, I went to casualty. Not Barchettaman´s finest hour.
Why stick mirrors to the windscreen? - IanJohnson
possible answers to original question

- Why not
- It is there
- Create and after market for sticky pads and superglue
- where else would you stick it - the headlining?
- better than no rear view mirror
- gives you something to hang the air freshener / fluffy dice from
- gives lady drivers something to check their makeup in downmarket cars without mirrors in the sunvisors.
- (to avoid being sexist) acts as a good shaving mirror



When re-fixing it use an adhesive pad designed for the purpose, make sure you clean the glass (e.g. Methylated spirits or the like) AND the mirror base including removal of all residue from previous attempts (one good reason why you should not use superglue, let them both dry for an hour before sticking it on. I have never had one I have stuck on come off.
Why stick mirrors to the windscreen? - wemyss
Why NOT use superglue when fixing a mirror to a windscreen.
A post on this site a couple of years or so ago from someone who seemed to know what he was on about gave a good technical explanation as to why not. Memory fails me but think it was something to do with unequal thermal expansion and the windscreen could crack.
Perhaps someone else will remember.....
Why stick mirrors to the windscreen? - Mookfish
possible answers to original question

- gives you something to hang the air freshener / fluffy
dice from


One of my pet hates, anything hanging from the mirror and anything else that gets in the way, eg child on board sign for each child and possibly one for the dog, and mums/dads taxi.
Why stick mirrors to the windscreen? - Dynamic Dave
>> As has been stated on a previous thread do NOT use superglue.

>>
Why not? Does it do something terrible to the screen?


Yes, it can crack it.

Don't beleive me, well, perhaps you'll beleive the words of a windscreen fitting expert then -

www.honestjohn.co.uk/forum/post/index.htm?v=e&t=28...0
Why stick mirrors to the windscreen? - wemyss
Well done Dave... Pleased someone remembered....
Why stick mirrors to the windscreen? - Mookfish
Well its stuck on with a proper pad now, and I made shure that I cleaned it properly so hopefully it will stay on this time.

I admit I did rush it when I originaly used a pad to reatach it and didn't clean it very well.

I assume the thermal expansion refered to above is when the metal base of the mirror expands more than the screen which causes the screen to crack. When I superglued it on I was using superglue to stick the pad that had come off the screen back onto the screen. Not the best idea ever I know but I was getting a bit annoyed with it.
Why stick mirrors to the windscreen? - AR-CoolC
I'll add to my previous post that Dave supplied.

Superglue will crack the screen, because as already said, on a hot day the metal mirror frame will expand a lot more the the glass will, this results in a loverly crack, that I get paid to sort out :)

If have a mirror that does need a double sided sticky pad (what car is it btw?) make sure bothe surfaces are nice a clean. Add a small drop of oil to the ball socket the "free up" the mirror, this takes the strain off the stick pad when you need to adjust the mirror.

Cheers
Why stick mirrors to the windscreen? - type's'
I think most rear view mirrors are welded to the glass in the factory with a new car and so are permanent.
It's just when you have your windscreen replaced that you then get the problems.
Why stick mirrors to the windscreen? - L'escargot
When the mirror is stuck to the windscreen instead of being attached to the bodywork above the windscreen it has a shorter "stalk" and hence has a more rigid mounting which minimises vibration of the mirror.
--
L\'escargot.
Why stick mirrors to the windscreen? - Number_Cruncher
Recently, I've been involved in the design of a similar joint on an instrument I'm working on, Titanium to Zerodur, using an epoy adhesive. Because of the application, I needed to demonstrate that the bond would withstand thermal cycling from -20C to 60C. From the resulting calculations and FE modelling;

The thicker the adhesive layer, the lower the thermal stresses are - some adhesive kits come with a mesh, this mesh is there to ensure you use a sufficient thickness of adhesive.

The co-efficient of expansion of the epoxy doesn't really matter if you already have sufficient thickness of adhesive. The reason is that the adhesive is much more compliant than either the glass or metal - in the sense of being less resistant to elastic deformation.

The detail geometry of the edges of the metal part can have a huge effect on the stress concentration - there's no way that automotive engineering would stretch to the machining processes required to produce the edge features that would avoid this stress concentration. So, the adhesive thickness must be increased to compensate.

So, in summary, I'm sure that you could get superglue to work if you use a sufficient thickness of adhesive, but I can see that a thin layer could cause trouble.

Some of my test joints begin their thermal cycling next week, which will be followed by a tensile test - I hope my calcs and analysis were adequate!

Number_Cruncher
Why stick mirrors to the windscreen? - mfarrow
Well its stuck on with a proper pad now


I'm glad you got it sorted. I used the Halfords ones a couple of years ago and found them to be fine, though the mirror does bounce around more than before, so I may well pay a visit to Ford's in the near future.

--------------
Mike Farrow
Why stick mirrors to the windscreen? - mfarrow
I may well pay a visit to Ford's in the near
future.


Have done, pad came to a grand total of 36p inc. VAT. With prices like that, trying anything else or an aftermarket replacement is just false economy. Mirror doesn't vibrate at all now.

--------------
Mike Farrow
Why stick mirrors to the windscreen? - Dulwich Estate
I still don't see why drilling a hole through the screen and using a big self-tapping screw into the mirror bracket wouldn't work !
Why stick mirrors to the windscreen? - autumnboy
Try pop riveting or drill and tapping then fit screws.????
Why stick mirrors to the windscreen? - madf
There is a new hi-tec welding which fuses steel to glass. It runs at 1200C tho...
madf
Why stick mirrors to the windscreen? - IanJohnson
Sounds interesting - Won't it burn the plastic lamination in the windscreen?

Nice brown mark around the mirror base!
Why stick mirrors to the windscreen? - Chris S
The mirror fell off my old Metro. I stuck it back on again with that 'No Nails' stuff.

It was still stuck on when I scrapped the car two years earlier. The windscreen didn't crack either.
Why stick mirrors to the windscreen? - Dynamic Dave
It was still stuck on when I scrapped the car two years earlier.


Earlier? You sure it wasn't a Delorean, and not a Metro?
Why stick mirrors to the windscreen? - Tomo
This might be worth a try:-

www.maplin.co.uk/Module.aspx?ModuleNo=46005&doy=se...h

I used something like it from Halford's years ago and it worked.
 

Ask Honest John

Value my car