Hi Jeff,
Jeff said:
My son just bought a used car which has an antenna mount for a satellite
radio stuck on the outside of the rear window.
There's a matching lump on the inside of the glass which I assume is
inductively or capacitively coupled to the outside piece, but he's not
much concerned with that one and if it happens to be stuck over one of
the defroster grid lines he's better off not messing wwith it.
I presume the outside piece he wants to remove is adhesively attached to
the glass and wondered if the folks here here can recommend a safe way
of removing it without risking damage to the rear window.
I spend a lot of time dealing with adhesives stuck onto
things (labels, "anti-theft mounts", etc.).
Since I am usually interested in removing them *without*
damaging the cosmetic finish of the item to which they
are attached, I am deliberately methodical and
conservative in my approach.
Labels are easy -- you can usually soak solvents *through*
them (though metalized labels like inventory control tags
and RFID tags are problematic).
For the sort of thing you are faced with, I would start with
a *small* (1.5") "putty knife". A *good* one -- not some
piece of crap from a discount store. The better knives
are thinner and made of a more flexible steel.
YOU WANT ONE WITH SLIGHTLY ROUNDED "CORNERS" (lest they end
up digging into the plastic coating on the safety-glass).
Try to work the center of the blade under a *corner* of the
antenna mount.
PATIENCE IS A VIRTUE :>
Your goal isn't to try to pry it off -- yet! Rather, you
want to *slowly* make progress under the metal/plastic
part by coaxing bits of adhesive to give up their grip.
As you make progress on a "corner", it gets harder to continue
making progress as your (assault) "front" becomes larger.
So, keep moving the direction of attack so that you are
addressing a newly formed corner.
E.g., a four sided region becomes *five* sided as you make progress
on that first corner. So, move to one of the *two* corners
most recently created to replace that one corner initially
attacked. That corner new will then eventually become the
*sixth* side, creating yet another corner, etc.
Depending on how large the area is and the strength of the
adhesive, I imagine you may need to get half way through the
area before you can expect to force it off (eventually, your
patience will wear thin :> )
You will probably end up with a bit of adhesive left on the glass.
You will need a combination of elbow grease and solvent to
remove this. Patience is, again, a virtue! Start with the
mildest solvent you can and gradually work your way up to
more aggressive solvents.
I always start with water (won't help *you*), then alcohol,
then mineral spirits. At this point, you typically haven't
damamged any of the surfaces you are working with
(notable exception is styrene).
Beyond that, its a judgement call based on the material:
MEK, acetone, xylene, benzene, and the other "ene's"
(polyethylene, marlene, charlene, etc.).
Note many of these are nasty -- read the MSDS before using.
One thing I have found surprisingly useful is a cleaner (?)
found in the 99c stores called "Awesome". It is probably
as nasty (biologically speaking) as any of the others
but seems to work well without risk of literally
soup-ifying some plastics (it will take the finish patina
off of plastic parts, though!).
If he (or you) don't want to be *patient*, then just replace
the entire window :-/
Have fun!
