Author Topic: Brazing with brass?  (Read 4361 times)

mjm46@bellsouth.net

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Brazing with brass?
« on: April 06, 2013, 03:14:53 AM »
I just picked up a MAPP gas torch. That thing gets really hot. Melts my scrap silver into a blob like nothing. It even melts brass.

My question is if I wanted to try brazing brass or steel using brass as the adhesive metal what would you use for a flux. I've never done this but I have tools that were brazed together with brass by my Dad and my father in law, both gone now. Anyone done this?

Offline Mark Elliott

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Re: Brazing with brass?
« Reply #1 on: April 06, 2013, 04:41:58 AM »
I just use Borax from the grocery store and silver solder flux from Hoover & Strong, but any borax based flux will do.   I do all my gun related brazing in the forge.   I only use a Propane/MAPP torch for silver soldering.   

wmaser

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Re: Brazing with brass?
« Reply #2 on: April 06, 2013, 09:51:22 AM »
You shouldn't have a problem brazing steel or iron (with brass) provided you use Oxygen and Mapp gas or the forge but you will have trouble trying to braze brass to brass, with brass. Depending on the specific alloy, all of the brass will melt at the same, or nearly the same, temperature. You will wind up with a melted glob of brass. You will have better luck using silver solder. It is available in different heat grades and can be applied with Mapp gas alone, without oxygen. To join large pieces with high heat silver use a second torch, as one will probably not give you sufficient heat.

Offline Rolf

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Re: Brazing with brass?
« Reply #3 on: April 06, 2013, 12:37:55 PM »
RIO GRANDE has an impressiv silver solder thats invisble on brass and flows at 650 degrees celsius. its item # 132201

Best regards
Rolf

Offline Mark Elliott

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Re: Brazing with brass?
« Reply #4 on: April 06, 2013, 09:38:31 PM »
I didn't want to imply that you couldn't used propane or MAPP for brazing, but for the work that I do,  the forge works better.    I just don't seem to be able to heat a large enough area to get the kind of brazing joint I want.   A propane or MAPP torch would be best used for very small pieces.

Offline David R. Pennington

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Re: Brazing with brass?
« Reply #5 on: April 09, 2013, 08:31:13 PM »
I agree Mark. I just brazed a rolled ramrod tip with an oxygen/acetylene torch. I got it done but it did not turn out as nice as bringing it up slowly to brazing heat on the forge does. I always say brazing in the forge looks like magic. You bring it up to temp slowly, (with the brass wire where it needs to be and well fluxed with borax) making sure all parts heat the same and it all happens at once! Poof!
VITA BREVIS- ARS LONGA

whetrock

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Re: Brazing with brass?
« Reply #6 on: April 10, 2013, 03:03:58 AM »
I agree. MAPP gas works great for small things, and it sure is handy. But it can't generate enough heat for big stuff. So use it for what it's good at, but understand it's limits.

You might want to check out web sites or even your library for info on soldering and brazing. Years ago I found a simple little book on those topics at my public library, and it saved me a whole lot of trouble. Following the instructions in that book, I didn't find brazing to be difficult _IF_ the material is hot enough.  But until it gets really, really hot, you'll find the brass (or brazing rod) sticks but won't run into the joint. Practice on some small bits and pieces of scrap first--some stuff that you can heat up easily. Then you will know what it looks like when it is working well. For small stuff, you may want to use flux coated (white) brass brazing rods. Very convenient and helps simplify the learning process.

Another problem is how to hold stuff. You sometimes have to make a wire jig to hold the parts, or actually rivet them together.  The amount of heat required sometimes prevents your being able to just hold them with a pair of pliars like you might hold something you hope to soft solder. So you have to think it through. Sometimes it helps to also "tin" both parts before they are joined. (That is, melt some brass onto the surfaces while they are separate, and then put them together and reheat them.)

Like Mark, I use borax. There is art in learning how much to use. The excess globs up in a glass-like mass that resists filing, but it can be chipped off.

Be sure to use good ventilation!

« Last Edit: April 10, 2013, 03:08:40 AM by Whetrock (PLB) »