Brazing rod price

[cathead]

Today I needed a tank of oxygen and some brazing rod to fix a leak in the hydraulic oil cooler on my Bobcat 853. I was fine with the
price of the oxygen which came to about $16.00 plus tax and $3.00 hazard fee. The brazing rods I wanted were the non-flux rods in
1/8 inch diameter and they had none at all stating nobody uses plain brass rod any more. Begrudgingly I bought one flux coated rod(3 foot)
at a cost of $2.50 plus tax. I didn't stock up so looking for something more reasonable. On the plus side, my brazing repair was successful
and after a test run I was happy that there were no leaks in the oil cooler. I don't know what pressure goes through the oil cooler but have to think it is not a low pressure line. With the price of copper at about $3.00 and zinc somewhat less, I find it hard to pay $25.00 a pound
for plain brass rods. I have done brazing with plain copper #12 house wire with success so may be opting for more of that in the future.
As far as the strength of brass versus copper, I would have to think copper would be a stronger braze than brass. Maybe someone
more familiar than I on the the subject can weigh in here. Thanks.

 

[benmychree]

What you are calling brass rod is likely in reality a type of bronze, made with copper, tin, and possibly other alloying elements, that is why, bronze rod does not boil and fume all over the place and show porosity in the finished braze; perhaps this is a case of apples and oranges, also perhaps brazing rod can be found elsewhere, uncoated and cheaper. mostly it is sold in a weighed packaged lot for reasonable money, granted it has been a long time since I had to buy any, as I brought home a good quantity when I sold my shop downtown.

 

[Nutfarmer]

I still use uncoated rod. I wonder if the bronze filler rod for tig would work? The uncoated rod will last a long time. The last flux I bought was half the size and in a plastic container. I like being able to control how much flux is used. You had better be sitting down when you see the price of refilling an acetylene bottle now days.

 

[David2011]

I still use uncoated rod. I wonder if the bronze filler rod for tig would work? The uncoated rod will last a long time. The last flux I bought was half the size and in a plastic container. I like being able to control how much flux is used. You had better be sitting down when you see the price of refilling an acetylene bottle now days.

I was SHOCKED at the price of acetylene. I have small plumber’s sized bottles and was quoted somewhere around $50 for the little bottle exchange. Thinking that bigger bottles might be more economical.

 

[bulgie]

What you are calling brass rod is likely in reality a type of bronze, made with copper, tin, and possibly other alloying elements, that is why, bronze rod does not boil and fume all over the place and show porosity in the finished braze;

Most of the so-called bronze filler rod has way more zinc than tin, so I will keep calling it brass, as I was taught in the '70s. The welding industry calls it bronze, and "experts" sometimes correct me when I call it brass. But I'm too old and set in my ways to change. BTW, the American Welding Society designation for LFB ("Low-Fuming Bronze") is RBCuZn, which means it's an alloy of principally copper and zinc. (Look up "brass" in the dictionary...) Typical LFB has about 40% zinc and 1% Tin. Not a typo, that's one percent tin.

My favorite is C-04 from Gasflux company. It's described as LFB with the addition of a little nickel, they say for for strength and flow characteristics. Note this is not "nickel silver", which has more nickel in it (but no silver!) Gasflux also makes nickel-silver, which is much stronger but doesn't flow as well. Stick with LFB if you are depending on capillary flow, like a sweat joint. Only use nickel-silver if you're building up an external fillet. Liquidus is higher for nickel-silver as well, which might be bad for applications that are sensitive to temperature (due to strength loss in the steel, distortion, etc.) Of course LFB, though lower-temperature than nickel-silver, is still a lot higher than silver alloys. Silver is obviously a lot more expensive though. LFB for best bang for the buck.

I also have some more generic LFB from Harris, that I got at the local welding store, and honestly it's hard to tell the difference between it and C-04. But back when I was brazing every day for a living (30 years ago), I decided I liked C-04 better. I'm less of a connoisseur now, and the generic LFB would probably be OK with me. Harris LFB has no nickel in it, so I assume it is weaker, but the strength of the joint doesn't necessarily depend on the strength of the alloy. A properly designed braze joint is stronger than the parent metal regardless of what filler alloy you use.

I only use bare rods, not flux-coated. I prefer paste flux. Gasflux company also makes excellent flux (as their name implies!)

Gasflux might sell direct, but I tend to buy it from a reseller I'm buying other stuff from already. Here's a pound for $17.
Here's a half-pound for $10 if you only need a few sticks.

 

[bulgie]

I have done brazing with plain copper #12 house wire with success so may be opting for more of that in the future.
As far as the strength of brass versus copper, I would have to think copper would be a stronger braze than brass.

Copper melts at a much higher temperature than brass/bronze. Like off the charts. It is done in industry sometimes, but typically in an oven purged with inert gas. It's hot enought that steel will burn badly if you do it in air. Paste flux for brass brazing is not formulated for such high temperatures.

 

[cathead]

Most of the so-called bronze filler rod has way more zinc than tin, so I will keep calling it brass, as I was taught in the '70s. The welding industry calls it bronze, and "experts" sometimes correct me when I call it brass. But I'm too old and set in my ways to change. BTW, the American Welding Society designation for LFB ("Low-Fuming Bronze") is RBCuZn, which means it's an alloy of principally copper and zinc. (Look up "brass" in the dictionary...) Typical LFB has about 40% zinc and 1% Tin. Not a typo, that's one percent tin.

My favorite is C-04 from Gasflux company. It's described as LFB with the addition of a little nickel, they say for for strength and flow characteristics. Note this is not "nickel silver", which has more nickel in it (but no silver!) Gasflux also makes nickel-silver, which is much stronger but doesn't flow as well. Stick with LFB if you are depending on capillary flow, like a sweat joint. Only use nickel-silver if you're building up an external fillet. Liquidus is higher for nickel-silver as well, which might be bad for applications that are sensitive to temperature (due to strength loss in the steel, distortion, etc.) Of course LFB, though lower-temperature than nickel-silver, is still a lot higher than silver alloys. Silver is obviously a lot more expensive though. LFB for best bang for the buck.

I also have some more generic LFB from Harris, that I got at the local welding store, and honestly it's hard to tell the difference between it and C-04. But back when I was brazing every day for a living (30 years ago), I decided I liked C-04 better. I'm less of a connoisseur now, and the generic LFB would probably be OK with me. Harris LFB has no nickel in it, so I assume it is weaker, but the strength of the joint doesn't necessarily depend on the strength of the alloy. A properly designed braze joint is stronger than the parent metal regardless of what filler alloy you use.

I only use bare rods, not flux-coated. I prefer paste flux. Gasflux company also makes excellent flux (as their name implies!)

Gasflux might sell direct, but I tend to buy it from a reseller I'm buying other stuff from already. Here's a pound for $17.
Here's a half-pound for $10 if you only need a few sticks.

Thanks, Bulgie for the interesting post. I will do some research and see if I can get some Gasflux rod, maybe the one with nickel and silver in it for future projects.

 

[bulgie]

Thanks, Bulgie for the interesting post. I will do some research and see if I can get some Gasflux rod, maybe the one with nickel and silver in it for future projects.

If you mean C-04 then yes that's the one I recommend. It doesn't have any silver in it though. It's copper/zinc mostly, just a smidge of other things like tin and nickel. Excellent all-around brass (aka bronze).