Windshield Repair Kits - do they work well?

I have a small impact on my on my windshield from a rock the size of a
pencil eraser along with a hairline crack about 1/4 inch long. I want
to have the windshield repaired so the crack doesnt grow. Most places
want $50 to repair it. My car is old and I plan to get rid of it in
the fall.
I noticed that Permatex and Loctite make repair kits for about $10
that include a syringe and a crazy-glue like adhesive that supposedly
fills the crack.
Can anyone attest to the effectiveness of these kits and the
difficulty in using them properly?
Thanks

 

I've tried them several times, practicing first on cheaper cars (was a
dealer). Never graduated to more expensive cars, as my expertise was
lacking. One really needs some specialized equipment(magnetized arms to
position magnifying glasses, proper heat source, proper light sources,
vacuum devices, glass-drills and training to fix them--esp. those having a
short crack. Thart short crack can run full width of w/shield before you
know it. Plus, I never could make the spots & stars virtually disappear,
like the pros could do.
Answer: pay the extra for a pro--the pencil-eraser-size would fade to
the size of the lead-pointed end; and the crack quite often is hidden and
they very seldom "run"--pros drill/fill the end of the crack to stop its
running. If it were me, I'd pay the $40 difference and feel as if I was
gonna get my $'s worth! Luck, whichever way you go. s

 

I used the permatex and fix-a-windshield brands on a very small
chip/crack. The permatex looked great for a few days then it was almost
like I did nothing. This was in winter so conditions were marginal. I
tried another application in better weather but didn't get a good seal. I
then tried the other brand that used a different application method. It
didn't do much. I couldn't get to the base of crack, but it got the rest
and that has held up for a couple months now. It is sealed, it's much
less visible, but it's far from perfect.

The only reason I tried it myself is because the damage was the kind that
would not progress any further if sealed up and is a
'have-to-know-it's-there'. If I should encounter this again, I would just
have it done.

 

I have a small impact on my on my windshield from a rock the size of
a

You have to follow the instructions _exactly_ to get good results.

I've heard that the Permatex/Loctite kit works well on bull's eye
damage but not for anything else. There's also a different kit,
consisting of 2-part epoxy, that works on both bull's eye and star
cracks, and a friend of mine had good luck with it. But it took
something like 45 minutes to apply the epoxy (he did it in the office
parking lot during lunch) because the plunger had to be manipulated in
different ways over the period to work into the entire crack and
remove air bubbles (push it down and hold it down with a pin, pull it
up and hold it up with a pin, plunge and release several times and
leave it down, pump several tiems and leave it up).

I'd rather spend the $50 to get the repair done right and prevent
further cracking that could require replacing the windshield.

 

They seem to work OK, and are easy enough to use. I wouldn't use them on
a long crack, but I filled a pit that sprouted a 3" crack on one of my
cars with one of these kits, and the crack hasn't grown any further and
the pit is much less visible after being filled.

 

If you care mostly about keeping the crack from growing, and don't care
too much if the chip stays there, you can stop-drill the crack with a
Dremel tool and a small silicon carbide stone. Dremel #83322 is ideal.
Drill just a bit beyond where you can see the end of the crack. Hold the
Dremel at just a bit of an angle, and rock it back & forth a bit. Be sure
to go all the way through the glass layer or you won't stop the crack;
it's pretty obvious when you hit the plastic. Then press on the area to
make the crack extend into the hole.

-Dan

 

You are not using a tungsten carbide glass drill (spade shaped)?

 

No, a silicon carbide stone. I've never tried tungsten carbide, so I
can't say how it compares, but silicon carbide is what Dremel recommends
for glass. I use this one, because it's the smallest diameter Dremel
makes:
http://www.dremel.com/en-us/attachments-and-accessories/attachment-accessory-detail.htm?H=188558&G=66321&I=66323

-Dan

 

Ok looks good. Have Dremel, will drill!

 

Are you cooling the glass when you drill? Adding oil or water to
lubricate?

 

No, in my experience it's not necessary. Of course it generates some
heat, but you can touch the glass immediately after lifting the tool.

I use a medium speed, and don't press hard, let the RPM's do the work. A
grindstone isn't made to go straight in like a drill bit, so you have to
wobble it a little, and I find it best to hold it at just a bit of an
angle. It'll take a few minutes to get through the glass.

-Dan

 

you don't want to do that if you want the sealant to stick!

 

Just a pinole with a bullseye, work pretty good. with a crack; maybe
not so good. you use the syringe to suck the air out of the bullseye,
then to fill it with crazy glue. if you can get rid of all the air,
the crazy glue almost matches the refractive index and it's almost
invisible. the original pinhole remains. with a crack, it has to be
small enough that you can effectively get all the air out without more
leaking in through the edges under the suction cup. then if you pass
that hurdle, the crazy glue doesn't really disguise a crack the way it
disguises the bullseye under the glass in the center of the
windshield. then, it doesn't have enough strength to really keep the
crack from propagating over time as they so often like to do.