Technical chop top cutting windshield to size

O.k. so top is chopped. I know how to cut glass. How do I measure it?
I measured old opening and then new opening. Cut a template to size. The template seems to tight in the new weather strip.
I am worried about cracking windshield due to stress while driving down the highway.
I can cut it to fit just don't want it to be to tight.

 

Use the windshield as a mold and make a fiberglass one to practice getting the size and shape right.

 

Assuming that you are just lopping off the top, take another 1/8" off, and put a thin bead of windshield cement on the new top edge.

That will prevent pressure, and the cement will keep it from moving.

 

Just cutting top of glass. 1/4 inch more seems to work better

 

Look at @Lloyd's paint & glass thread, He likes to sand off small bits, not try to break them off.

 

I'm not sure how the real glass guys do it but If I had the original glass I'd lay it on something stiff enough to make a pattern out of, trace it out, cut it out and then cut it in two straight across and overlap the pieces in the opening to get my glass size. I figure to do that on the windshields and side glass on my 48 and then cut out 1/4 inch masonite to the size and do the fitting with it before loading the truck up and hauling it to the glass shop. I'm just not hard core or cheap enough to want to install my glass myself again.

 

Try masking with silicone and rubber tyre strips then sand blast at 45 angle . keep pressure as low as possible and just keep at it . worked for me on 59 Rambleher

 

It's like a torque spec, or boring a block, creep up on the final size with the belt sander. You've gotta sand the edges anyway to rid it of stress risers.

 

What car? Flat glass or curved? Flat is easy. If it is curved and you are just now trying to fit it to the opening you are already bass ackwards. Fit should have been considered first before cutting metal.

 

My car is a 54 chevy. Curved glass.
I brought this up because others have asked about windshield installs. Weather stripping etc.
Just wanted to help some out on chopped top windshield installs.
I had a friends crack after about 2 months of driving.
I don't want that to happen to me or anyone else.

 

Yeah Jerry, if it's under stress anywhere in the gasket, you can bet that it will crack! Glass doesn't bend very well lol. But after you cut it to your desired size, if it needs some adjustment, 80 grit aluminum oxide sanding belt and a spray bottle of water will move a lot of glass. Buy you a whole pack of belts lol. And you can finish the edge with 120 or 150 seeing how it's not exposed, like the top of a door glass. I have a $75 craftsman belt sander, and it works just fine.

 

Thanks Lloyd. I will be trying it again next spring.
I have to finish the wife's Nova first.
I'm going to order a new windshield soon. I hope to get back to working on it soon.
Work is really busy right now so not much time for cars.

 

And, don't forget your safety gear. Sanding glass is dicey in a handful of different ways.

-Abone.

 

I would like to reshape a curved rear back glass from essentially a rectangle to an isosceles trapazoid like this: The curved sides would remain but the top total glass width would be closer than it is right now. The lower total glass width would remain the same. Make any sense?


I picture 4 cuts which would remove 2 pie shaped pieces. Is this even possible with tempered 1959 glass? If so, what kind of shop should I be looking for? (please excuse my complete lack of knowledge on glass). thanks

 

If it is tempered, it can't be cut til its untempered. Otherwise it will just shatter. Untempering is even harder than tempering, I've read.

 

thanks... anyone had a custom curved glass made?

 

Unless you are chopping a car with flat glass, you should cut the glass first, and fit the metal to the glass. Unfortunately that won't work now. Through the years I have seen lots of chopped cars sold without glass for cheap prices cuz no one could make the glass fit the opening.

 

I think this is a wise idea... I just mocked up the back window with a 6" chop and I really like the look. (and putting it back together is within my neophyte skill set)... I think the process will be get the opening where I like it. Maybe a form that I can flip side-to-side so I know they are the same, then create a full size template. Not sure how I might do this... cardboard then fiberglass? Look for a custom glass place like this one https://www.procurveglass.com/ or just use lexan... any thoughts?

here's the victim...

 

wetskier, a side picture would help, from the one you've posted the only option I can think of is 1970 Camaro back glass

 

You could always sink the factory rear glass. Then there would be no cutting involved.
A quick search brought up this thread. There are others as well.

53 chevy chop sinking rear glass | The H.A.M.B. (jalopyjournal.com)

 

off subject-I have a friend who works at making special gaskets-rare cars to space rockets. He has access to a hydo water cutter they can use after work. It will cut thru the glass- steel- rubber all at once- not taken apart-perfect cut. good for reducing roadster wind shields and curved glass. ask in your area- they are around. Not recommended to purchase- several hundred grand !

 

Could always see if you can find a windshield with similar contours to cut.

 

I had seen the references to sinking the glass into the trunk but I also leaned the c pillars in at the top so that method won't work for me. On donors, the closest I could find would give pretty large sail panels with smaller glass. It would really change the looks... I did, however, have some very nice junkyard tours of older iron while looking.

Does that water hydro cutter work on tempered glass without shattering it?

 

No. Once you remove a bit of tempered glass, whether it’s a small chip or grain from the edge or the middle, it will shatter. I’ve seen it explained as if the piece of glass is a balloon, yet a very flat balloon. Once you take a nick out of the surface of the balloon the whole thing explodes.

 

Coincidentally, I saw a motorhead show last night where they cut a new, curved windshield for a 1955 Ford pickup to fit a chop. The windshield was laminated and the process was relatively straightforward. It doesn't help me at all but it was cool to see. The rest of the truck's glass was all flat that they cut to size from new stock.

It's amazing to me that the little glass cutter tool works at all. It seems to essentially just score the glass. The pro doing the work said he had about a 90% success rate on curved glass.

 

I was told decades ago to do just that. Cut the glass first, and chop the top to the glass.

 

ive always thought all cars from our era were safety glass? every pane on my '57 ford is laminated.

 

Most rear glass was tempered in the late 40's and 50's on up.