Thread: Piping for oil tank

I meant to check this piping with a magnet, but forgot. I originally thought it was copper, but then looked closer and it appeared to be steel tubing. My question relates to the joints. Copper was permitted for use in oil tank fill or vent pipes if the joints were brazed. Can anyone tell from the photo whether this is a brazed joint. If the pipe is steel then I assume solder would not stick properly. The pipe may be undersized by present standards, but I am interested in this case whether this would have been compliant in 1971. You are welcome to comment on present codes, but in this case that is not my interest.

P7274874 (512x384).jpg

Looks like a brass elbow, not copper.

Originally Posted by Raymond Wand

Looks like a brass elbow, not copper.

Raymond, You are correct about the elbow. My question is in regards to the piping. I typically see black iron or galvanized steel, but some installations were copper. This looks like steel tubing, but as I mentioned, I forgot to check. I am more interested in the joints-brazed versus soldered.

Can be done, but the joints have to be really really hot and I believe you have to use solder with about 40-50% silver and good flux.

He polished the ends of the pipes, and there are no lumps of bronze at the joints. I vote for skillful soldering.

Looks like ductile iron pipe. It can be soldered and often is.

Fwiw

Brazing vs Soldering | Lucas-Milhaupt

Brazing vs. Soldering
Brazing - The American Welding Society (AWS ), defines brazing as a group of joining processes that produce coalescence of materials by heating them to the brazing temperature and by using a filler metal (solder) having a liquidus above 840°F (450°C), and below the solidus of the base metals.

Soldering - Soldering has the same definition as brazing except for the fact that the filler metal used has a liquidus below 840°F (450°C) and below the solidus of the base metals.

And this is the key difference between soldering and brazing - Temperature at which the filler melts. (it also is used to define what materials are used to make up the joint which speaks of strength and other characteristics - would I braze/solder this joint - no , why because a threaded joint can move with vibration if needed (like earth quake)

Originally Posted by Raymond Wand

Fwiw

Brazing vs Soldering | Lucas-Milhaupt

Brazing vs. Soldering
Brazing - The American Welding Society (AWS ), defines brazing as a group of joining processes that produce coalescence of materials by heating them to the brazing temperature and by using a filler metal (solder) having a liquidus above 840°F (450°C), and below the solidus of the base metals.

Soldering - Soldering has the same definition as brazing except for the fact that the filler metal used has a liquidus below 840°F (450°C) and below the solidus of the base metals.

- - - Updated - - -

And this is the key difference between soldering and brazing - Temperature at which the filler melts. (it also is used to define what materials are used to make up the joint which speaks of strength and other characteristics - would I braze/solder this joint - no , why because a threaded joint can move with vibration if needed (like earth quake)

Originally Posted by Raymond Wand

Fwiw

Brazing vs Soldering | Lucas-Milhaupt

Brazing vs. Soldering
Brazing - The American Welding Society (AWS ), defines brazing as a group of joining processes that produce coalescence of materials by heating them to the brazing temperature and by using a filler metal (solder) having a liquidus above 840°F (450°C), and below the solidus of the base metals.

Soldering - Soldering has the same definition as brazing except for the fact that the filler metal used has a liquidus below 840°F (450°C) and below the solidus of the base metals.

Originally Posted by Lon Henderson

Looks like ductile iron pipe. It can be soldered and often is.

How do you solder ductile iron pipe?

Guess you have never heard of pipe thread shear?

Originally Posted by Raymond Wand

Guess you have never heard of pipe thread shear?

What has pipe thread shear got to do with soldering ductile iron pipe?

why because a threaded joint can move with vibration if needed (like earth quake)

It was in reply to Dwight.

Originally Posted by William Heuberger

How do you solder ductile iron pipe?

I've never soldered it. From your question, I judge that you don't think it can be soldered. If I am mistaken and the tubes in the photo aren't ductile iron, then what are they? I see similar material occasionally and I see it soldered, so I'd like to know what it is. Somewhere in my past, somebody told me it was ductile iron. Is there some reason why unlined ductile iron pipe can't be soldered? I did a bit of research and see a reference to repairing cracks with solder and another about welding it but the welding was for large pipe.

I appreciate the replies. Getting back to the intent of my post, I was curious as to what type of pipe or tubing was used. I typically see black iron, galvanized steel, or copper. Many home inspectors flag copper as not being permitted. Past codes (and maybe present-I have not looked this up recently) allowed copper IF the joints were brazed, not soldered. I understand that brazed joints are typically dull, not shiny like solder. I would say they look more like soldered joints than brazed, but I'm not sure. I was hoping someone out there could easily tell the difference so that I and others would have a good idea as to whether joints were correct or not.

Maybe an HVAC guy who brazes copper lines will comment.

Here is another photo:

P7274875 (512x384).jpg

It looks like steel or stainless steel tubing and cast bronze elbow. As was mentioned earlier, it is the temperature at which the filler melts that determines whether or not it is soldering or brazing. The dividing line is 840F. Both silver brazing and tin solder will stick to steel, copper, brass, bronze and SS. The filler cannot always be determined from just appearance, although most solders can be easily scratched with a pocket screwdriver. The hardness of solder is usually less than brass, bronze, and even copper. While brazing is a harder material than copper, brass, and even bronze, in most cases
The one thing you that you can count on. Soldered joints are low temperature (usually below 500F.) and the pipes never change color. Brazed joints use fillers with an 1100F melting point or higher, except in special applications. When you heat metal to 1200F, it will glow a dull red and you know it is ready for the filler. At the same time a permanent bluish/purple coating forms on most metals. I do not see that color here. IMO this is solder unless the plumber had a source of an 850F brazing material, which may not have been a high enough temperature to change the color of the tubing and fitting.

I vote steel (or stainless) tubing, brass elbow, silver soldered.

Originally Posted by Phil brody

I vote steel (or stainless) tubing, brass elbow, silver soldered.

Yes and how likely would it be expensive stainless, on a simple tank vent, not too likely.
A magnet would have proven it is steel, mild steel if you like, but then we would not have this discussion.

BTW, where's the stain from the flux?

Since this thread has generated some interest, and differences of opinion, I am going to try to post a higher resolution cropped photo to show more detail. Maybe this will answer some questions or prompt other replies.

P7274874 - cropped.JPG

I see flux stains, and I think this is a soldered joint not brazed.