A quick search on Google for “Classic Auto Glass” turns up dozens of online businesses selling curved glass that would have been difficult or challenging to find just a few years ago. Most of these businesses stock flat glass templates for early cars as well. Most of these businesses are limited to domestic cars, but enough serve foreign brands to cover classic imports.

But when you’ve got your glass in hand, what then? Installation can still be tricky, but there are some tricks that help you with this part as well.

The most common situation for older cars is to have a rubber gasket around the edge of the glass. There’s a channel for the glass on one side of the rubber, and a channel for the window frame on the other side of the gasket. To install a window like this, you’ll use some heavy string like clothesline and some detergent-based lubricant like Simple Green in a spray bottle.

First, get the rubber gasket oriented correctly around your window glass -this is often trickier than it sounds. But make sure it’s right or at a minimum, your window will leak. Once the glass is well-fitted into the rubber, take the assembly and put it in place on the outside of the window hole. Spray the gasket liberally with your lubricant and put the string all the way around the gasket channel with several inches of string dangling out at both ends, which should be together.

Now you need a friend to help by gently--and we do mean gently--pressing in on the glass. Get inside and pull one end of the string out to pull the lip of the gasket over the ridge of the window frame. The lubricant will help the rubber squeeze through the gap. Continue carefully pulling the string until the lip is pulled in all the way around the window frame. If you crossed the two ends of the string, you should get the whole lip in without difficulty.

Note that this technique takes a little bit of practice! Don’t hurry and don’t work when you’re frustrated. It’s easy to do this, but also easy to break or crack your new glass.

The other options for mounting glass are removable frames with clips, gaskets, or glue, or simply gluing the glass into the window frame. With removable frames, you can usually disassemble the frame and get the glass out. Replacement rubber is easy to find because it’s not a single piece around the whole window, but rather just a piece of gasket that can be cut to the correct length.

Gluing the glass into the frame came into vogue in the 1960s because it was cheap for automakers to build cars this way. Of course, all that glue has long-since fossilized, leading to millions of cracked windshields over the years. It also means that it’s next to impossible to remove a glued-in windshield without breaking the glass. Special “hot wire” cutters are used that burn/melt the glue away. Then you get to chisel or cut out the remaining glue! It’s best to take care of that when you disassemble your restoration and really clean it.

If your glue-in windshield has clips or some other firm fastener holding it in place, consider replacing your windshield with black silicone RTV instead of the black hardening glue that is made for windshields. The RTV will hold the windshield in nicely and it’s 100% easier to remove if you ever need to take the window out again. But it’s not as strong as the glue, and your windshield could potentially pop out in a panic stop or if someone pushes against it from the inside. So some additional fastening is generally required.

Roll-up window glass poses a special challenge - you need to take apart the door to get this in place, and make sure that you restore all the channel felt at the same time, and that you get the winding mechanism working well. It’s annoying when your windows don’t roll up and down the way they should.

Whatever style of attachment your glass needs, you can call a professional automotive window glass installer if you want someone who has done the job a few times. They’ll generally do the job with your provided glass for a small fee, and they’ll come to your house or shop to do it.

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