What do I need to Braze steel to steel?

[Stomis]

Heres a pre-emptive. I've never brazed before. Also dont have any clue how to do it. I was under the impression you used brazing rods and a mapp gas torch just like soldiering pipe. I think I'm wrong.

I bought a pack of brazing rods from lowes to tighten up the fit between my square tube shaft. Well when I did my tube rockers I remember I had them. So when I trimmed the doors I figured I should try to braze them lol. Well I went at it with the torch and got nothing lol. I could barely get the rods to melt.

Do I need a true oxy-acetaline torch to do it? The rods I have are covered in flux and for some crazy reason I'm thinking they actually look like sticks for a welder...


Scool me!

 

[ryoken]

ya need an oxy setup with a brazing tip.. they come in many sizes... most torch kits come with a couple... a VERY long lost art imo... not many guys know how to do it any more... it happens to be one of the things i'm very versed in, from back in the body shop/resto days.. prior to mig welders, we brazed all our qrters on, etc...

 

[KirsL]

It's also extremely easy to screw up whatever you're working on if you're not careful. Can get great results with it but it takes some practice.

On a side note I've actually used my tig welder to braze, much more control, but you can get the same results with a torch.

 

[Stomis]

Yeah after some more reading I think I may have bought brazing electrodes for a stick welder. They do exist from what I've read. Idk guess I'll nix that idea for the doors and just use them on the shaft as a bushing.

 

[Fordum]

Stomis, if they are brass with a white soft coating on them, Scratch that, make that any color soft coating on them, they are probably torch brazing rods.
Last ones I bought were blue......

I may get flamed on this one, pun intended, but brazing is basically high temperature soldering.
You get the metal hot, touch the rod to it, and the flux melts and lets the brass alloy form a mix with the steel.

The main problems with it, are the heat you have to get the metal to, less than welding, but usually in a larger area.

But, you will need the full oxy rig with a brazing tip. You can use a standard cutting tip, but you do not get the heat control you really need.

If you have done any soldering, just use the same techniques. Keep touching the rod to the metal until it gets hot enough for the rod to melt.

 

[Stomis]

Stomis, if they are brass with a white soft coating on them, Scratch that, make that any color soft coating on them, they are probably torch brazing rods.
Last ones I bought were blue......

I may get flamed on this one, pun intended, but brazing is basically high temperature soldering.
You get the metal hot, touch the rod to it, and the flux melts and lets the brass alloy form a mix with the steel.

The main problems with it, are the heat you have to get the metal to, less than welding, but usually in a larger area.

But, you will need the full oxy rig with a brazing tip. You can use a standard cutting tip, but you do not get the heat control you really need.

If you have done any soldering, just use the same techniques. Keep touching the rod to the metal until it gets hot enough for the rod to melt.

Okie doke. Got it. I figured it was just a stronger version I soldiering. And I did read that its heat the work and feed the rod into it. But how the hell do you braze body panels then? Wouldnt heating the work warp the **** out of say a quarter panel?

 

[Fordum]

Okie doke. Got it. I figured it was just a stronger version I soldiering. And I did read that its heat the work and feed the rod into it. But how the hell do you braze body panels then? Wouldnt heating the work warp the **** out of say a quarter panel?

Yep.
Its doable, but you need a small tip to keep the heat localized, and you're going to have to accept some warpage.

That is why spot welding or TIG has pretty much done away with brazing in a lot of instances.

I had to do a lot of brazing on the sheet metal of some Coke machines several years ago, and I got pretty good about controlling the warp, and even using cold water to warp it back the way I wanted.

In that case, I would have loved to have options, but it was braze or nothing.

Most of the time, you have to do the brazing, then heat and shape the metal back like it was.

 

[ryoken]

I would somewhat question the comparison to soldering, your not really sucking it into a joint.. and tho many times you can, and especially amatuers, make it a larger, thin puddle-type welds.. thus i'm assuming the correlation with soldering.... you most certainly can lay bead with brass and a brazing tip...

I probably brazed my first 50, 60 qrters on, and tons of rust repair too.... not alot of guys out these days that can torch-weld... MIG and TIG have definitely killed that skill.....

 

[4X4HIGH]

They say if you can braze then you'll be able to TIG weld. I have never tried a TIG welder but I can braze pretty good (at least 27 years ago or so when I last did it).

 

[ryoken]

They say if you can braze then you'll be able to TIG weld.

i believe it.. very similar technique, tho i don't TIG... i kinda look at torchwelding these days as a poorman's ancient TIG welding...

the nice thing about brass is it's so soft to grind... the bad is it has bad adhering qualities... you HAVE to coat that seam (in the case of a patch) with a fiberglass filler, not a bondo.... or go straight to primer..

 

[Fordum]

I would somewhat question the comparison to soldering, your not really sucking it into a joint..

Now that is funny. It shows how a person's life experience affects their thinking.

When I said soldering, you immediately thought of sweating tubing.

While I have done a lot of that, both in refrigeration and plumbing, most of my soldering has been in electronics or assembly IE, putting things together with solder.

If someone were to run into my house yelling they had to have some solder quick, I would automatically toss them some 60/40 rosin core.

You would be more likely to throw them some 50/50 with some flux.

All in what you are used to.
As for sucking braze into a joint, I'm like you. I guess it would work, but not sure I have ever done it.

If I were patching a hole in a body panel by cutting the hole out, say square, and using one of those tools that recesses a lip and laying a piece of replacement steel in the lip, I would be more likely to lead solder it in place than braze.
Less heat, and lead is more galvanic friendly than brass, I think.

Just tin both parts, wash off the flux, lay the panel in place and heat until it settles down smooth.

Assuming you are lucky enough to be working on a flat piece, of course.

For tiny surface areas like an edge to edge seam, then weld or braze for strength.
By making little "spot brazes" along the seam and then coming back to fill in the gaps, you would minimize warping.

BTW, heres one for you. When I have to attach copper tubing to steel, I use silver solder.
Although its hotter than regular soldering, its pretty much still soldering. And thats what I call it. Soldering or Silver Soldering.

So, what is the official term when you attach two pieces of copper tubing with PhosCopper?

I usually just say I am going to PhosCopper them, but it just does not quite sound right.