Galvanized tube

Joe_Dunham

My daughter bought a house circa 1950 construction. The hot water heat was done well with monoflo tees and bent takeoffs to the risers. But the main looks like 1” galvanized ( I checked it with a magnet) tube, not pipe , and the fittings are copper. It joints are sweated just like straight up copper. Anyone work with this? I need to move a section 

Intplm.

Have seen that before but found that the main was painted looking like galvanized when it was actually copper. Could this be the case on this tube?

Danny Scully

If I’m not mistaken, GM made this tubing? I believe it’s the same size as copper though and you can press onto it. If press isn’t available, consider a compression transition. 

mattmia2

I think you should be able to solder to it with copper fittings if you prepare it properly and use the right flux and are careful to flush that flux out. I would be concerned about it developing pinholes at this point if it has the same wall thickness as copper since the minor corrosion that happens with steel wouldn't have far to go to perforate it.

Joe_Dunham

It’s magnetic so it’s surely steel. So you think there’s a special flux? Not the ordinary stuff?

hot_rod

It might be what was referred to as Bundy tube?

pecmsg

Steel / Copper can be Brazed!

WMno57

WMno57

https://refresearch.com/how-bundy-tube-helped-win-the-war-and-the-hearts-of-the-appliance-industry/

Bundy tubing has been a staple of both the automotive and refrigeration industries from their inception. It began when Harry Bundy, a former mechanic at Detroit Steel Products, developed a process for forming a double wall steel tube capable of withstanding extreme high pressures.

The first contract Harry received was a big one with the Ford Motor Company. Henry Ford needed someone to make the gas lines for the Model T. At that time in 1920, the Model T accounted for roughly half the cars on the road world wide. Bundy double wound his tubes from a single strip and brazed the seam. He provided the tubes to Ford in straight lengths. But, when the Ford workers bent and shaped the tubes to fit the Model T chassis, the brazed seam split rendering the tubes useless. Needless to say Henry was not happy.

Undaunted, Harry went to work on fixing the problem. He decided to coat the tube with copper before rolling the sheet around itself twice and then brazing the tube in a hydrogen atmosphere brazing furnace. This made the tube more resistant to shear as it was formed. It also made the tube more corrosion resistant and cleansed the interior and exterior surfaces. Bundy went one step further, he didn’t leave the bending and the shaping to Ford but instead supplied the tube pre-bent according to the Ford specifications. This arrangement with Ford facilitated their assembly process and it became the relationship model for future automotive suppliers. Ford began to rely on the expertise of their suppliers to feed their modern assembly line process.

EdTheHeaterMan

Great find for the military use of that Bundy Tubing. I think the related article is even more interesting.

WMno57 said:

WMno57

Mad Dog_2

It could be Tubealloy..Mad Dog 

DanHolohan

Where is this?

pedmec

I had the same issue about 20 years ago. i brought the pipe to every supply house and everybody i knew. unfortunately nobody knew what it was. i was able to transition to copper using water service adapters. An old timer suggested that it might have been pipe (or tubing, don't remember) from the Quincy navy yard.

Joe_Dunham

This is Suffolk county New York. I think it may have been created during the war where  brass and copper were in short supply. 

EdTheHeaterMan

DanHolohan said:

Where is this?

I think it is in some guys daughter's basement. But I am not sure Dan!

Mad Dog_2

Tubealloy, used extensively in Nassau County (Franklin Sqaure, New Hyde Park, Wantagh, Seaford) new homes built after WW II.  Looks like gray  steel tubing. I was amazed that you could solder it.  Used on hot water with connectors. Mad Dog 

mattmia2

Mad Dog_2 said:

Tubealloy, used extensively in Nassau County (Franklin Sqaure, New Hyde Park, Wantagh, Seaford) new homes built after WW II.  Looks like gray  steel tubing. I was amazed that you could solder it.  Used on hot water with connectors. Mad Dog 

it might be tin or terne plated for exactly that reason

PRR

Mad Dog_2 said:

......you could solder it.....

AFAICT, BundyWeld started in the early 1930s as an improved car hydraulic brake line. It is steel with copper coat, rolled and soldered/brazed to give a double-layer wall. It has to take solder.
It was (still is) produced for most of a century for several markets and market-conditions(*), so there will be variations.
It may "look like galvanized" if terne-dipped for a final finish, but probably isn't actual Zinc in house plumbing. Obviously copper or terne will solder great.

(*)Copper was a very "strategic material" in WWII. It was proposed to replace copper voice-coil wire in radio loud-speakers with Silver. Technically as good as copper until you get the bill. But copper was good for so many other things that it could not be spared. Even coming out of the war it may have been used as super-thin platings mixed with baser metals and hardly copper-color at all. In fact the way it rots in car-brake application suggests that the copper is not very substantial.