Aluminum Brazing Rod Is Very Easy To Use Once You Learn How

[toobroketoretire]

After paying $40 to get my TH700R4's broken aluminum tail housing TIG welded (and getting a lousy job) I decided to do further experimentation with the aluminum brazing rod I bought last year from Harbor Freight for $15. I experimented on a few pieces of scrap aluminum and quickly found out what you should NOT do; pointing the torch flame (propane, MAPP, or acetylene) at the rod itself.

Here's step-by-step instructions of what you need to do to braze aluminum:

1. Either sand the aluminum to bright and shiny or glass bead/sandblast it to remove all oxidation

2. "V" the crack just like you would for any crack repair

3. Heat the cracked area to 725-750 degrees, point the torch away, then apply the brazing rod into the 725-750 degree "V" and it'll flow into the V just like any lead/tin solder would flow

4. Allow the repair to completely air cool all by itself because water will make the repair very brittle

By the way, the repaired joint will be a LOT stronger than the parent metal.

To watch aluminum being brazed Google "Brazing Aluminum" and there are dozens of You Tube videos on the subject.

 

[toobroketoretire]

Here's Another Hint On Brazing Aluminum

If you're going to braze something real thin an ordinary propane torch will do but for thicker materials like bell housings or tail housings you need to use something a LOT hotter like MAPP gas or oxygen/acetylene because aluminum dissipates heat so fast. I was finding 1/4" thick aluminum needed close to 5-6 minutes of heating to get the brazing (soldering) rod to melt into the heated material. Remember, you NEVER point the torch at the rod when you're brazing (soldering) aluminum. Let the HOT material melt the rod and it'll flow into the joint just like hot solder would flow into a brass or copper joint.

 

[Mac]

A couple of guys at the office have been playing with the MIG welder and aluminum, trying to teach themselves how to weld. I wish I had time but the best I can do is not complain about them wasting time/material. lol

I did some stick welding when I was a kid, then a bit of MIG welding on sheet metal when I was restoring an old Jeep several years ago. Maybe as part of my active retirement, I'll finally take some classes and learn how to do it right.

Mac

 

[toobroketoretire]

A couple of guys at the office have been playing with the MIG welder and aluminum, trying to teach themselves how to weld. I wish I had time but the best I can do is not complain about them wasting time/material. lol

I did some stick welding when I was a kid, then a bit of MIG welding on sheet metal when I was restoring an old Jeep several years ago. Maybe as part of my active retirement, I'll finally take some classes and learn how to do it right.

Mac

After paying $40 to get my tail housing TIG welded and getting a LOUSY job I decided to experiment with my Harbor Freight aluminum brazing rod more. I watched a few You Tube videos and realized the trick is to NOT point the torch at the rod; only at the metal and then let the metal melt the rod. And as the rod is being melted continually rub the rod against the metal to scrape the oxidation off. Yesterday I bought a MAPP torch and 2 bottles of MAPP gas and it does a LOT better job at heating the metal; about half the time. I also bought a container of brazing flux as the flux helps prevent the aluminum from oxidizing during the brazing operation.

 

[Tom Bryant]

I have this rod in my shop. It's easy to use with just a little practice and you can repair many things that you would have taken to a specialty welding shop and paid big $$ to get repaired before.

Tom

 

[toobroketoretire]

Aluminum Brazing Rod Flux

I tried using brazing flux made for brass and it didn't work at all because it has a higher melting point than the aluminum brazing rod. So I ended up with a really bad weld. There is a lower melting point flux made specifically for aluminum brazing so I'll buy and try some of that. There is also aluminum brazing rod available that has a flux core so I'll buy and try that too. Like anything else there is a learning curve needed for brazing aluminum and one of the best ways to learn is by watching a bunch of You Tube videos on aluminum brazing.

 

[toobroketoretire]

Just Ordered More Rod And Flux

I just tried using synthetic motor oil as a flux (per a You Tube video) and it worked surprisingly well. But I went ahead and ordered another 1/2 pound of aluminum brazing rod and 4 ounces of powdered aluminum brazing flux so when I receive them I'll do more experimenting. The powdered flux starts off as a solid then it changes to a liquid just before the metal is hot enough to melt the rod so the flux can also be used as a temperature indicator. I love to learn new things.

 

[Tom Bryant]

Synthetic motor oil. You learn something new every day.

Tom

 

[toobroketoretire]

Synthetic motor oil. You learn something new every day.

Tom

The synthetic motor oil kinda worked but the brazing rod barely adhered. After it cooled I smacked it with a 2# hammer and it easily broke apart; the weld being pretty dismal even though it looked terrific. When my flux arrives I'll try it and see if I end up with better welds. If all else fails try doing it the RIGHT way, right? But I'm having a lot of fun learning just as I learned to use stick rod about 50 years ago.

 

[toobroketoretire]

Aluminum Brazing Flux

I got the special aluminum brazing flux and it makes a HUGE difference. The flux is a white powder that begins to melt about 50 degrees under the brazing temperature required and it prevents the aluminum from oxidizing during the brazing process. The flux is around $15 for 4 ounces so it's a lot more expensive than ordinary brazing flux for cast iron.