Restoring Original Glass: Part II

Restoring Original Glass: Part II

Save Money by Restoring Original Glass

I’ve written about restoring original glass before, but at the time I hadn’t perfected my process.  Also, because I hadn’t remembered to take any before photos, it was hard to show the difference a little elbow grease made.  All that’s about to change!

The Labor Day weekend was super productive.  Once I had the windshield re-installed without incident, I turned my attention to the back glass.  Before I even started dealing with the glass itself, I fixed the four molding studs I’d broken off by installing the ’65-style screw in clips.  NPD normally sells the clips as a complete set to do a full window (or both), but they also offer a small bag of five clips if you just need to repair a few broken studs.  You’ll need to buy the screws separately, too, but you’ll still save a few bucks over buying a bunch of clips you don’t need.

Glass is expensive and delicate.  But apart from the possibility of breakage, it’s extremely durable.  As long as it’s intact— absent chips or cracks or delamination— restoring original glass is relatively straightforward, albeit time-consuming.

For more than a year I’ve left the back glass sitting outside behind the garage.  I figured since the car had sat outside since 1978, another year wouldn’t hurt.  Most of the environmental damage had already been done.  Dirt comes off easily with a few passes of window cleaner and some water.  But the hard layer of well-cured crap left by a combination of rain, dust, organic matter, sun, and time…that’s harder to remove.

Getting Set Up

When you work with glass, be careful and take your time.  The moment you get careless and rush you’ll end up cracking the glass, turning your work into a throw-away.  Get your work areas set up before you move the glass.  Trying to position everything while you’re holding a large piece of glass is asking for trouble.  I set up two stations, one for the initial cleaning and one for the detail work.

Remove the Loose Dirt

For the initial cleaning, I set up two municipal trash cans (the kind with lids) next to one another.  That makes a firm but forgiving work surface for scrubbing.  With the hose on low pressure, and armed with a blue scrub sponge and some Bon Ami powder, I went to work.  The goal here is to get the loose dirt off; don’t scrub too hard or you’ll end up scratching the glass.  I sprayed the glass down first, sprinkled the powder on, and then scrubbed gently in circles.  I flipped the glass over and repeated the process on the other side.  After drying the glass off with a cotton towel, I moved it to my detail station.

Focus on the Detail Work for Great Results

Detail work involves cutting through various layers to get down to clean, shiny, smooth, clear glass.  It’s this process that’s the biggest hassle in restoring original glass.  Before I could polish anything, though, I had to remove the remnants of old sealer.  3M General Adhesive Remover is almost a miracle cure.  It dissolves and softens the sealer enough that it’ll scrape off with a plastic pry tool.  Another round or two of spray and a paper towel gets the rest of the sealer off in short order.  With the sealer removed, you’ll have a good idea of the work remaining.

If you’re working on a car that hasn’t ever been out of service, you’ll probably be able to stop here.  Having removed the sealer, you’ll basically have a clean piece of glass.  A spritz and a wipe with some glass cleaner and it’ll be as good as new, ready to reinstall.  But if you’re resurrecting a car that should have been left for dead long ago, or you’re trying to save some glass from a  junkyard find, keep reading.  Chances are you’ll need to remove the baked on layer of dried gunk that seems permanently bonded to the glass.

Dealing with Baked-On Junk

The most efficient method of removing the cooked-on film I’ve found is to use 0000 steel wool with rubbing compound and medium pressure.  For various reasons, the bulk of the film is usually concentrated at the bottom edge and corners of the glass.  After scrubbing the edges extensively with the combo, I also did a full, light pass on both sides for good measure.  Watch out for the etched on logo and try not to scrub it too hard; I imagine you could polish the logo off if you aren’t careful.  Wipe off the compound with a damp towel to check your progress, and keep going until you’ve got a nice, shiny surface left over.

Finishing Up

Having refined my process for restoring original glass, I was able to take the back glass from junk to gem in about two hours.  Seeing as it took me that long to do one vent window the last time, this was a huge improvement.  With the glass clean and shiny, I started to put the gasket on, but then I realized it was the same foreign-made junk as the first windshield gasket.  Having already fought one of those, I decided to store the back window and order a US-made gasket from NPD.  Once that gets here, I’ll have the back window installed and every piece of glass will be in the car!