Brazing, how difficult is it?

D

dml66

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I've got a wireframe magazine rack I'm particularly fond of where one of joints broke loose, it's probably made of some sort of cheap steel. The joint pieces are 90° apart, maybe 3/16" diameter rods. I have several torches, MAP fuel, Butane and Propane. Just wondering if brazing the joint might work? If so, what brazing rods and flux would be appropriate?

Thank you.
 
Brazing with propane or butane isn't likely to succeed although with proper insulation around the joint to retain the heat, it may work. The MAP gas in 14 oz. containers sold by Bernzomatic isn't real MAPP gas. Production of MAPP gas halted several years back. However, the Bernz product is hotter than propane. A backing of an insulating material like firebrick will help. At the brazing temperature, most heat is lost through radiation. I can't help with the brazing rod as I haven't bought any in decades.
 
C-Bag said:
With what you have and the size wire I’d solder it. Done right it is really strong.
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I needed to attach a steel pipe to a steel drum for a dust collector a few years back. Really thin metal likely to burn through welding or brazing. I soldered it and it was rock solid.
 
You will not burn through steel unless using an oxy-fuel oe forced air torch.



Solder would not be an option for me for a joint that was previously spot welded. I would try the MAP torch on some scrap first to see if it is capable of brazing two wires. Update: I tried brazing a piece of 1/4" key stock with my Burnzomatic MAP gas torch and it wouldn't fly.

There is a low temperature brazing rod called Miracle Rod, I believe. It is a zinc alloy and purported to braze any metals. The requirement is that the surfaces are absolutely clean of any oxide but it is a significantly stronger joint that solder. I tried that on the same key stock and it easily brazed the stock. The Miracle Rod was a trademarked product and may not be available any more but it was touted as an aluminum brazing rod. Bernzomatic sells a n aluminum brazing rod called AL3 which is a 93% zinc alloy and I expect is the same alloy. There are also other vendors selling similar products for aluminum brazing.\
 
It would strengthen the joint if you wrapped the joint with copper wire prior to soldering. Use a fine bare copper wire. Cat 3 telephone cable is a source of light gauge solid copper wire. The solder will impregnate the wire, increasing the bond strength.
 
I agree it would increase the strength but depending on how much wire you add and how you do it, it can change the appearance. I brazed in shop class before I soldered so I know how both processes should be done and how like so many things it’s all about the prep. And then the proper flux and correct solder along with proper heat and technique. None of us except the OP knows the amount of background he has in any of this so it’s hard to know how to make suggestions.
 
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