I am working on the restoration of one of the wood-body/iron-under-frame Barney and Smith cars (blt. 1912) here at the Northwest Railway Museum. It has 64 stained glass windows, a third are semi-elliptical for over the side windows and the remaining are the rectangular clerestory windows. Each window has multiple panes in zinc framework. Some are salvageable and will be put into the restored wooden frames if I can learn how to solder the zinc frame work.

The problem seems to be that the zinc is highly corroded/oxidized. I've tried cleaning it with everything I can think of including paint stripper and muriatic acid. A wire brush won't do it and though sandpaper is pretty effective the zinc is too brittle for much sanding.

I've tried flux and resin core solder. A Weller soldering gun won't work and a really hot soldering iron makes the zinc disappear. Not melt. Disappear!

What is doubly frustrating is that it clear that when a pane was broken, the zinc framework opened up and then resoldered. I have yet to find a window that has all the original panes of glass. How come they could do it and I can't?

I hope somebody has solved this problem.

--
Where the Weather Suits My Clothes
Volunteering at The Northwest Railway Museum
Snoqualmie, Washington
http://railfan44.rrpicturearchives.net/
Marty Bernard

I would be cautious.. I wish I could help you with your task at hand, but I will say coming from a family who worked for New Jersey Zinc, the zinc was precipitated from flue gas in the furnaces.. That is, it was in a gaseous state, and that explains why your soldering causes it to disappear.

Zinc in quantities just around 10 times the normal daily recommendation can be lethal. That would be around 150 milligrams for a lethal exposure.. Please proceed accordingly, and best of luck with your project.

MJK

Perhaps stained glass artists in your area could provide you with some hands-on coaching, and maybe point you in the direction of suppliers who can get you the specialized materials you require.

dave

We talked with a stained glass artist who only works with new clean metals. He was no help with the problem. BTW, there are materials and glass available that are similar to what was in the car. Many windows will have to be made that way since not nearly enough is salvageable from this and other similar scrapped cars.

It is not that difficult to work with stained glass. I have been doing it as a hobby for years. The most important thing you need to keep in mind when soldering is corrosion free and clean surfaces.

Old zinc, especially if it's dirty, been painted or it's corroded is almost impossible to solder. The older it is the more brittle, crumbly and difficult it is to get solder to bond. Even if you are lucky enough to get a tiny joint to bond, the chances are that the zinc will crumble right next to your joint. There are many profiles of lead and zinc "came" available commercially and there are a few historic suppliers of special profiles to the restoration industry. If your pane is of the "cast" variety, a new cast zinc "frame" for your glass may be another option. Although a new casting may be expensive for one window, it would give you a chance to replace any other frames that may be questionable. As I mentioned before, the old zinc will be brittle. If your car will be used in service, other panes may begin to come apart.

Good luck. If you have any other questions regarding your stained glass project, feel free to ask.

Bruce Mowbray
Springville, PA

Does the zinc came look different than the lead? If you end up having to replace all of the metal (and some of the glass) then if lead is easier to work with you might as well go that way. Maybe find out if there are any hobbyists who would be willing to donate their services or do the work for a small stipend.

Steve

Just for the record...soldering glass frames (lead or zinc) is nothing like soldering wire. It is a different skill set. A Weller iron or gun will not cut it. You need a hot iron (not a gun) with a wide tip. The solder is allowed to flow onto the joint...you do not heat the came like you do when soldering wires together. We have been able to do some repairs to some very trashed pieces...just takes a lot of work and patience. Now that I said all of that...repairing old pieces is a lot harder then building new ones. It is dangerous, frustrating and you quickly learn that the craftsmen of old were not able to make pretty cuts like we can do with the new generation of cutters.
You can find companies that specialize in restoring old glass from church windows and so fourth. They are costly and there is a reason for that.
T7

I wonder if there mgiht be a modern epoxy or other adhesive / sealant that would do what the solder did without damaging what's left of the old zinc, maybe helping consolidate it in the process? It sounds like there's a definite life expectancy for the original technology which is about used up, so perhaps replicating with modern came and solder recycling the original glass would be the only other option.

dave

When new, zinc is slightly brighter than lead (more aluminum in color). I does turn grey over time and loses it's bright luster.
Zinc came is actually alloyed with lead and tin. Zinc came is not as flexible as lead came. Lead came is very soft and can be bent around tight corners. The amount of zinc in the came alters the melting point so that 50/50 solder can be used without melting the came. Zinc, being not as flexible, can be a better material for larger window panels and mobile (like trolleys and railroad cars) applications. Lead came tends to move over it's lifetime if the window is not supported by an external skeleton. There can also be varying alloys of lead, zinc, and tin depending on it's final use.

Bruce Mowbray

This jumped out at me. Son works with a lot of O-scale prewar, and one of the prime problems with them is zinc pest. Impurities in the cast zinc lead to intergranular corrosion, and the metal slowly cracks and crumbles. You're dealing with it on a much bigger scale, but odds are that's the problem. I have literally seen pieces of a 1938 Lionel engine fall apart in front of me.

Does it look as if the metal is crazed, like old ceramic glaze? Look at a broken piece under a microscope. If it's zinc pest, it won't look like a typical broken edge; the break will look grainy, with bright sharp crystals sticking out of it.

It's possible to use epoxy to bond crumbling zinc, but even with beloved old model trains it's not likely to work terribly well. I'm all for maintaining historic fabric, but your best bet probably is to replace the window frames and preserve reasonably intact ones for static display. If you get the car moving, the window frames are apt to keep cracking in different places.

ETA: Son just reminded me to tell you that any frames that are unaffected now are not likely to be affected at all. He says 1912 was very early in zinc casting technology and that's why so few of the original Dorfan and Ives model trains have survived--some crumbled in the boxes before they were sold. Think on a bigger scale and this article may be of help:
http://www-personal.umich.edu/~khmiska/ ... nkpest.htm

Thanks for all the input.

One of the members, Rick Wilkins, says he uses lye to remove corrosion and about everything else from RR Lanterns. Hot water. Soak over night. A coating of carbon remains on the zinc. Lye carbonizes everything because it is so alkaline. It comes off with a little work. And I could get solder to wet it. But I sure didn't want to soak a whole window frame and glass and have to clean that up. So I wet well the area of the zinc around the crack in the frame and sprinkled on lye crystals. After about a minute and then clean up I could solder at least small breaks in the zinc frame. More practice needed, but it works.

Bill Hall showed me the windows last May... (by the way, your restoration shop is wonderful)

I suspect they may be leaded glass (i.e. "stained glass") windows in a zinc frame, but as late as they were produced could be all zinc, either way the solution is the same.

Generally, when restoring leaded glass windows, you completly dissasemble the window, remove all the lead came (or zinc), replace any broken glass, then rebuild the windows using new came as if building a new window. You can't clean old lead or zinc sufficiently to solder to.

You have to be very careful when cleaning art glass windows. If leaded, the lead is very susceptible to accelerated corrosion... i.e. conversion to white lead putty. Ammonia is a really good accelerator... I would worry about lye as well. Generally in museums, you clean art glass with a soft brush, and possibly clean water. The glass is very stable, but the lead or zinc isn't.

Additionally once assembled, the windows have a putty worked into the joints between the glass and lead (or zinc) to seal them.

The life expectancy of a leaded glass window in California is about 120 years if exposed to weather. After that it has to be disassembled and rebuilt.

Your windows are very simple, and would be easy for a experienced glass artist craftsman to repair and or replicate. Bill said the glass was Kokomo, a still available brand, although a exact color match may be difficult.

Hit me off line, I may be able to help

Randy

At the encouragement of an interested reader, I'll de-lurk with some photos/tricks (probably obvious to stained glassers, but maybe not to rail preservationists) from my workbench.

Here's an image of a minor repair I made to a stained glass window for an interurban car at the Rockhill Trolley Museum. It is all zinc came and frame. I made the spot repair since it was easily accessible without rebuilding the entire window (I've seen the normal, complete-rebuild method on other windows). After sanding the zinc to shiny metal, I was able to get what I think is an acceptable bond with my regular gel flux, 60/40 solid solder, and Weller 80W iron. I put a couple of splints on either side of the new frame joints for reinforcement. I suppose time will tell.



This is a complete reproduction that was needed to complete the set. The cardboard scraps under the glass pieces keep them raised up to the groove of the came, so that while things are loose and being positioned prior to soldering, the glass doesn't fall all the way out and cause a headache. The deep sockets on the table are dies for bending the zinc came by hand.



For the center of the arch, I held the zinc at either end and applied gentle pressure while pulling it across the edge of the workbench. For the tighter radii as the ends, I used this homemade jig. The upper photo has a plain metal bar stuck in for show. The twin dies can pivot as the floating die is hammered in. Grooves in the dies, shown in the lower photo, hold the profile of the frame to prevent buckling. It held up fine for one window, but it might need metal dies if one wanted to make a whole set of windows.