Need assistance with learning to braze.

By - Date 11-04-2003 03:33

i want to braze mild steel to mild steel.I just don't know the correct procedures?....I wish somebody could list them in order like even maybe some pictures!....

I for example can just do just this so far with a bare rod!

I dip a small part of the heated rod into the flux to obtain some.

Then I heat the base metals like a lap for example to dull cherry red.

Then I don't know what to do from there and how for an example would I go about brazing with a pre-coated rod?....Does the precoated rod have to be heated up.Remember I am new at this process but willing to learn as days go by.

Once the flux is on the rod what do I do?....Do the base metals have to have flux already on them before?....I need someone to explain step to step but I can't find any instructional details on the handy harman site for brazing mild steel to mild steel.I know you have to have the metal heated to a cherry red state but what do I do?

When I dip the flux coated rod into the heated part do I dip it back in forth like gas welding? or do I melt the piece of flux coated rod with a torch onto the metal pieces or do I add flux to both the rod and the work pieces.Now I am just getting totally confused because I had a pre-coated rod and touched it onto the metal and nothing happened like they said the filler would melt and cause capillary action but I sure didn't see it?....Do you apply flux to the working pieces and on the rod on all brazing methods including aluminum,copper etc..? I seen the way the guy did it on muggyweld.com for two pieces of aluminum but I still do not understand.My hobart book says to apply flux to the metal pieces being brazed and then add flux to the rod and I guess you just heat the work pieces then to dull cherry red but then how will you tell when flux is covering it? And how do you melt the rod onto the heated parts to be brazed? I need a lotta help!!?!?

By RonG

Date 11-04-2003 16:55

Brazing for the most part is no different that Oxy/Fuel welding but not to be confused with Silver Solder.

Dull red will not do the job for steel, You want the filler to flow into the work not just lay on top.

Clean is a must, no rust or scale not to mention oil and dirt.

With precoated filler you need only to clean your work real good before heating. Do not preheat the filler rod

Powdered flux are much the same only you will need to heat your filler rod and dip it in the flux to coat it. Heat the end of the filler rod with your torch

Most paste flux can be put on before heating but after cleaning.

Most of the time you want a Neutral flame (sometimes Cast Iron requires more oxy). Torch size matters in conjunction to the cross section of the work and the filler.

If you are working thin sections you might try laying down one puddle at a time until you can follow the flow of your filler. Heat a spot to almost melting then add filler, back out and let it cool for a few seconds. Repeat that process over lapping roughly half of the last puddle.

Don't use a torch so big it will burn through your work before you can add filler. Use a torch that can apply enough heat to allow you to work at a confortable pace.

By jwright650 (*****)

Date 11-04-2003 17:00

RonG,
I think you probably explained it as good as anyone could. I think the Welding Handbook that AWS published is another good source of info on this process. The one I have is an old one, Volumen Two, Seventh Edition.
John Wright

By SteelDet (*)

Date 07-10-2004 14:40

I am new to gas welding/brazing. I have done quite a bit of arc welding though. If I understand correctly, the difference between gas welding and brazing is...to weld you actually let the base metal melt some before touching the rod to it, and when brazing you just heat both pieces to a cherry red and then touch the rod to it...right? In both cases you never touch the rod with the torch flame (except to heat before dipping into powdered flux)? I brazed for the first time lastnight and couldn't get the rod to melt without flame. I was connecting a 3/16" stainless rod to about a 5/16" thick steel horse shoe. I did it kinda like a plug weld, I drilled a hole in the horseshoe and stuck the s.s. rod thru and had it about 1/16" (+) below the surface of the horseshoe. I concentrated the flame on the horseshoe until it was cherry red then the s.s. rod easily turned bright red, but the brazing rod wouldn't melt if I removed the flame first. I was using the coated bronze brazing rods, probably not the right rod, but it seemed to work, looks good and seems strong enough for what I am doing.
So, was I just not getting the base metals hot enough, or is it ok to melt the rod with the flame as long as the base metals are cherry red and you don't boil the bronze?

By billvanderhoof (****)

Date 07-11-2004 07:13

I keep the rod near the flame so it stays warm then dip through the flame onto the surface of the metal or into the puddle after you get going. The rod should melt on the surface if things are hot enough. The rod should not melt in the flame and then drip onto the surface.
Bill

By SteelDet (*)

Date 07-11-2004 17:13

Thanks, At first I was moving the flame away then touching the rod and it would just stick. Then I did basically what you said and produced a good looking braze that is definitely strong enough for what I'm playing around with.

By jwright650 (*****)

Date 07-12-2004 11:19

http://www.jwharris.com/home/

This is a link to a site where I look for info concerning brazing/soldering. Check it out, they have several pages of good info to help choose the correct filler for the materials you are trying to join. There are some good safety guidelines listed as well.
Hope you find this usefull,
John Wright

By swnorris (****)

Date 07-12-2004 22:17

Hi SteelDet,

The link below is to the Army's training circular. Scroll down to 11-14 Brazing. This link is for ferrous materials.

http://www.machinist.org/army_welding/Ch11.htm#s2

This link is for nonferrous materials.

http://www.machinist.org/army_welding/Ch11.htm#s4

By cnsupplier Date 01-07-2005 08:02

China Brazing Rod Manufacturer & Exporter
http://www.brazing-china.com

By cnsupplier Date 01-11-2005 07:50

China manufacturer and exporter of welding alloys, brazing rod, soldering materials and other correlative products.

http://www.brazing-china.com

By welder5354 (**)

Date 01-15-2005 23:56

WallMountain or WMC has an excellent video on Oxy-ACT. Welding that would be excellent for a wanna-a-be. Try it! you will find its great. I use it in my class to give first year students an overview of the oxy-acetylene process. This video has excellent and clear demonstrations of "How to braze in all positions".
wallmountain@weldingvideos.com.