gluing glass to neoprene?

[micky]

And that's good, since I don't have to worry about every little thing breaking it. I used to fear that at first.

[jim beam]

it's not listed for that application, yet if you get it on glass, you have a devil of a job getting it off. so i guess we're down to whether or not we're actually speaking from experience rather than reading from a non-manufacturer website, and the definitions of the word "stick".

[jim beam]

ever seen the little safety hammers by bus and train windows? they weigh less than 1lb, but will smash tempered glass with ease because they have a hardened point that will initiate cracking, and with tempered glass, that crack instantly progresses into the thousands of small pieces that the glass then becomes.

if you have to smash tempered glass, get a piece of broken spark plug insulator, place that on the glass sharp side down, then strike that with a hammer. works every time.

[Ron]

That's IF the 3M tape will work. You would think if there was a way to repair the glass on these tops when they fail that the top/upholstery shops would repair them. EVERY person that I spoke to told me the same thing, "the glass and top is laminated together when they are made, and we have no way to do that". There is at least one company now that is making tops and giving a lifetime warranty on the glass coming loose. It is a company called UltraMaxx

[Ron]

It will not stay stuck to glass. When I was in the glass business people (DIYers) would try to reglue door glasses that had come loose from the channel with it.

[Steve W.]

And actually MUCH easier to destroy the whole piece at once. Just chip the edge or create a rapid high stress point on the surface.

The high stress point has to be a POINT though, even a hammer head diffuses the impact enough.

Use a sharp pointed hammer though and it will take out the glass with a mild tap.

We use glass hammers, spring punches and even car antennas to take out glass during extrication.

For laminated it's harder, especially some of the new structural support glass. With that a sawzall and a glass blade work well. Evan the glass master is hard to work with on that stuff.

[Ron]

A piece of spark plug ceramic itself will break a piece of tempered glass for some strange reason. Tempered glass will break easily if you tap it on the edge...especially the corner. And I believe those hammers were phased out by spring loaded center punches.

[micky]

That's right. If it doesn't work, it will last me even longer.

Shops don't want to do a job that might fail soon, because even if you warn customers, a lot of them will complain. They prefer to do the job the way they know will work.

When the pipe broke off from my cat. converter, every muffler shop I went to in my n'hood wanted to install a new cat. No one would weld the pipe back on. So I went half way to t he center of town, to a lower middle class n'hood, or upper lower class. (It's hard to tell because the commercial street looks a bit run down, but the street with the houses a block away looks nice.) and the first muffler shop I went to was happy to weld it for me, put two beads all around the pipe, and charged me iirc 30 dollars. I gave him 40. His repair lasted for years, until I got rid of the car for other reasons.

So that doesn't mean this tape will work, but that shops don't want to do it doesn't mean it won't.

I'll bear this brand in mind, in case I need a window. (I had a back up plan in mind if this tape doesn't work on my car (maybe the window is taller and heavier than for a Corvette) but now that I find the window bumps into the rear seat back, my back up plan isn't as likely to work.

BTW, it says that with glass windows, sewing was out of the question. At the start, sure, but by now, can't they make a window with a row of holes around the perimeter?. Then sew the canvas on. That would take the strain and some lightwieght glue could glue some fabric over the stitches.

[micky]

I didn't believe spring-loaded center punches would work in metal, until I tried one.

[jim beam]

it's not strange, it's just outside most people's experience. it's all perfectly normal if you're a fracture mechanics and stress concentrations geek.

edge effects. glass surfaces are flawed. flaws can propagate into cracks. tempered glass works by using tensile stress within the core to compress surface flaws so they don't easily progress into cracks. but you can't compress an edge because one of your three dimensions is missing. on a corner, you're pretty much removing two of your three dimensions. so, no compression means easy crack propagation.

often, yes. harder to get wrong if an operator is panicking.

[jim beam]

i've found it to work well enough on rubbers, the op's application. but you're right, it wouldn't be great on solids like window hinges.

[chaniarts]

if it was tempered (and a previous post said it was), holes would be a stress point and would shatter pretty easily during normal service if anything hit it around that edge. you'd need to have rubber inserts on the holes to prevent that.

[jim beam]

rubber is used to prevent stress concentrations from the fastener, not so much that they themselves are the problem.

now, the holes /can/ be a problem, but there are rule as to drilling method, size and placement that pretty much remove risk. i forget the numbers now, but as you say, you have to keep certain distances from edges, use holes above a certain size relative to glass thickness, make sure hole edges are smooth and that they don't get overly stressed. done right, you'll not notice any difference in service strength.

[micky]

So I gather, prior to getting the tape I need, if I continue to let my window go thump when the top edge of the window passes the top rear edge of the rear seat, I have a greater risk than normal, a pretty high risk, of the window breaking. ??

When the Lebaron separated from the curtain, it was at the bottom of the window and the top went down and up as usual. In fact, after trying 2 or 3 times, I eventually realized I didn't even have to fix it, because the rain ran down the window, into the vinyl lower boot, and out the drains.

[Jim Yanik]

jim beam wrote in news:j87tvh$3nk$ [e-mail]:

it's tempered glass because in a collision,it breaks up into little pieces instead of dangerous big shards that will cut you.

a spark plug is what thieves use for their smash-n-grabs. or a spring-loaded centerpunch.

[chaniarts]

you can hit a tempered window with a baseball bat numerous times, and it won't usually break. the hitting is not cumulative. you can scratch it with a nail and it will shatter the first time.

tempered glass is formed by cooling the outside faster than the inside, putting the outside in tension and the inside in compression. glass is very strong in compression, very weak in tension. the differing force is released during a scratch on the surface or edge.

it's great fun to set off a tempered sheet of glass, but you'd be picking up glass chunks for quite a while. i use shattered tempered glass to build art pieces.

[jim beam]

other way around - the core is in tension, outside in compression.

yup. and tempered glass is strong because the tensioned core is not at the surface where the flaws are.

it's the tension force. if you introduce a flaw deep enough that it reaches the core, then it goes.

have you ever played with "prince rupert's drops"?

[Ron]

The back glass on the '82 - '92 Camaro and Firebird is a perfect example.