<VV> brazing help needed

[Larry Forman]

At 08:21 PM 5/27/2004 -0400, John McMahon wrote:
>Anyone out there know how to braze?  I haven't actually needed to do any on
>my car, but it seemed like a neat trick to add to my small collection of
>skills.  I went out and bought a flux coated rod, and tried my hand at it
>with very little success.  I figured maybe the 1/8" rod was too thick for
>what I was trying to do, so I turned it down on the bench grinder and used
>flux from a can.  Still nada.  The ONLY way I can get it to flow is if I
>heat the steel until it is ALMOST MOLTEN, and then put the rod on it and
>direct the flame at the rod.  I have tried this with pieces of metal from 18
>gauge on up to 1/4", and can't get it to work like Finch and others say it
>should.  What am I doing wrong?   Maybe the hardware store variety of rod is
>not what I need.   I am using a regular oxy/acet welding outfit, BTW.
>
>Thanks,
>
>John McMahon
>1965 Monza coupe

Hi John,
It is quite similar to soldering, but at higher temps.  Try smaller pieces 
of metal, like steel washers you want to braze onto a piece of THIN steel 
sheet metal, non-aluminum, or brass is wonderful also.  Having a thin part 
will gain you some confidence faster.  Heat the washer and sheet metal it 
is setting on.  Warm the brazing rod (hardware store rod and flux is fine) 
and place the hot rod into the flux and it will stick like a coating onto 
the rod.  Heat the washer and sheet metal again and touch the flux coated 
brazing rod onto the hot metal.  You will see the flux start to melt and 
then the brazing rod will melt i if you have the temp just high enough and 
the metal will flow toward the hottest places.  Move the torch around so 
you heat it evenly and the braze rod will melt and flow evenly.  Try 
several washers until you can braze them onto the sheet steel or brass.  I 
would not advise doing this on your wife's car, however.  LOL.

You do NOT need to heat until red, just to the melting point of the braze 
metal.  It is over 580, or solder temps, but less then welding or 
cutting.  If you heat too much you will drive off the flux and it will not 
allow the flowing process.  You add more heat as you see the braze rod 
start to melt.  Direct the heat where you want the melted brazing to go.

You will find it is actually pretty simple.  Just make sure your parts are 
clean, and taking sandpaper to the surface should help.  No grease or grime 
allowed.  You might be able to do something similar to aluminum, but it 
would take special alloys and flux.  Stick with ferrous materials 
(magnetic) for starters or brass.

It can be quite fun and is not difficult, once you get the hang of it.

-- Larry