Brazing 101 ,the wonder glue

NASTYZEN · Oct 7, 2011

Often overlooked ,yet so simple, brazing is like a poor mans T.I.G.
There's all kinds of info on TIG,Mig and plasma here, but very little on brazing?
If you are going to do any kind of fabing in your garage, other than a hammer and grinder.You are going to need torches. Of the Oxy-Ace type to get any serious heat.
With a regular coated utility brazing rod and your heat. You can join metals such as steel,stainless steel,copper,bronze together and with special and specific fluxes, you can join Aluminum by fusion as well as brazing.
Also,you can solder with lead,silver solder.
I use a Fluxer setup on my torches. The flux comes out the torch.

It's cheaper than keeping a TIG machine in your shop and it's mobile.

With torches,you can also heat and cut things. I love my torches. :thumbup:

Be careful, they are great for starting fires in the shop also. Have a couple fire extinguishers on hand and move the trash can away.

Front upright from a 944.

First I tig welded the ear back on after v grooving and thoroughly sanding it clean. I could of Oxy-Ace welded it but I have 2 T.I.G. machines ,So why not :lol:

Preping is critical with brazing. The base metal has to be a little rough for good bonding. Just like for gluing.

I preheated the area with my cutting torch first.
I use low fuming bronze of 1/16'' dia.

Should be good till it comes off again!
:beer:

Jim Stabe · Oct 7, 2011

Brazing definitely has its place and does a great job in the right applications. The Brits used to put their race car frames together that way because you can use very thin walled tubing and not destroy the strength next to the weld joint (the heat affected zone). Many high end bicycles are made that way for the same reason. Technique and joint design are important and you get some really pretty fillets if you do it right.

njride · Oct 7, 2011

Must of been interesting when that upright let go

CaseyJoes. · Oct 7, 2011

I have silver soldered before to repair small parts, and fabricate things where I needed to connect two different metals, such as brass to steel. Silver solder will work great making a strong connection with two thin peices of metal if you get them cleaned and prepped properly. Such as a thin sheet metal brace that was originally spot welded to a larger structure but spot weld cracked out, or something along those lines. Silver solder repair was stronger than a single spot weld and is also very discrete (no weld bead showing)

Omphaloskeptic · Oct 7, 2011

Wow! I always thought brazing was a small step above soldering (strength-wise). If I understand your method correctly, you used the TIG for strength and followed with brazing for buildup purposes, yes?

CaseyJoes. · Oct 7, 2011

Omphaloskeptic said:
Wow! I always thought brazing was a small step above soldering (strength-wise).

If I remember correctly, using the right type of brazing rod the braze can be just as strong or stronger than the metal that it is joining?

NASTYZEN · Oct 7, 2011

njride said:
Must of been interesting when that upright let go

Actually was mild.It was still bolted to the remaining ear. About 1/6 of a turn on the wheel.

Jim Stabe said:
great The Brits used to put their race car frames together that way because you can use very thin walled tubing and not destroy the strength next to the weld joint (the heat affected zone). it

Yes, this is why I got myself a fluxer long ago. For 700 bucks at the time,it's paid for itself many times over.

This is brazing on a Lola. .050sheet to .125 wall tube
Preparation is everything, almost

Tack the corners.

Brazed up.

CaseyJoes. said:
I have silver soldered before to repair small parts, and fabricate things where I needed to connect two different metals, such as brass to steel. Silver solder will work great making a strong connection with two thin peices of metal if you get them cleaned and prepped properly. Such as a thin sheet metal brace that was originally spot welded to a larger structure but spot weld cracked out, or something along those lines. Silver solder repair was stronger than a single spot weld and is also very discrete (no weld bead showing)

Silver solder is great because some of the alloys can have a lower melting point than bronze. It also has great wicking properties.

Omphaloskeptic said:
Wow! I always thought brazing was a small step above soldering (strength-wise). If I understand your method correctly, you used the TIG for strength and followed with brazing for buildup purposes, yes?

From memory, about 78,000 tensile. That will vary depending of the rod alloy.
I could of fused it with the oxy-ace torch also. But it takes less time to tig it up. I metal welded or fused it because the base metal is a forging. If it had been cast I would of brazed the entire thing.
I also kept the bolt hole in there for safety or fail safe.

CaseyJoes. said:
If I remember correctly, using the right type of brazing rod the braze can be just as strong or stronger than the metal that it is joining?

Yes, today's alloys are awesome.

CaseyJoes. · Oct 7, 2011

NASTYZEN said:
Silver solder is great because some of the alloys can have a lower melting point than bronze. It also has great wicking propeties.

x2 on this. It is so satisfying to watch a properly cleaned and fluxed joint seemingly "drink" up the silver solder as you feed it into the joint and it wicks it way around the joint. Clean it up and you are left with an attractive & strong joint. :beer:

theoldwizard1 · Oct 7, 2011

NASTYZEN said:
Often overlooked ,yet so simple, brazing is like a poor mans T.I.G.

...

It's cheaper than keeping a TIG machine in your shop and it's mobile.

...

First I tig welded the ear back on after v grooving and thoroughly sanding it clean.

First you say it a cheap alternative to TIG (in some cases). Then you start the repair with TIG. If you have TIG, why not use it to do the complete repair ?

NASTYZEN · Oct 8, 2011

theoldwizard1 said:
First you say it a cheap alternative to TIG (in some cases). Then you start the repair with TIG. If you have TIG, why not use it to do the complete repair ?

Because the pin is 4340 and I didn't want to mess the temper up by shocking it with the high temperatures of fusing.

BTW the repair was entirely TIG because the pin and upright are two separate pieces. The broken ear was the problem. But because it already broke once, I decided to fail safe it by brazing the whole shabang together. This car runs slicks and gets lots of track time. It should spread the loads better.(and brake somewhere else :dunno:

)
Another benefit of brazing is that later, if we choose to change the pin or upright.you can easily grind off the bronze and you haven't affected the temper of the part.

NASTYZEN · Oct 8, 2011

This may be a better example of a brazing weldmend.

It's for a quad or something.

Prep.

Tack.

Done.

Quick n simple. Cheaply done.

I have special nickel alloy rods for arc welding.They don't come cheap.
I have some for my TIg as well, also expensive and frankly I don't trust the integrity of repairs made with nickel arc on this kind of stuff anyway. It tends to be on the brittle side of things.
Bronze will deform a whole lot before tearing.
I am fortunate in that I have seen so much destructive testing in this industry to now know what works and what works not as well.

38D · Oct 8, 2011

Nice work NZ, but I gotta ask, why not just a new (used) upright? Those steel 944 uprights are only like $150 IIRC.

NASTYZEN · Oct 8, 2011

38D said:
Those steel 944 uprights are only like $150 IIRC.

Where???You have to get a whole car up here.They have become scarce.

Nick M · Oct 8, 2011

Can you explain the technique, like where to hold flame and how to work the rod? Thanks!

AZ_Catskinner · Oct 8, 2011

Good stuff! I have long been a proponent of brazing and the acetylene torch in general.

A brief warning though, this is a recent discovery for me that raised more than a little bit of alarm. DO NOT BUY Chinese import coated rod!!! I picked some up to do a quick "road" project with the MAPP torch, and I discovered that the flux was mostly PLASTIC. Burnt the holy hell out of my hand when the flux coating IGNITED, and probably took 3-4 years off of my life from the fumes.

Nick M said:
Can you explain the technique, like where to hold flame and how to work the rod? Thanks!

There's dozens of techniques out there, and everyone's is a little bit different. The basics for mild steel are to heat the joint to a dull cherry red, then start laying down your bead of brass as you would with an acetylene or TIG weld. You just slowly feed the rod in, you don't work the rod at all. Your bead comes from puddling/torch motion.

Zengineer · Oct 8, 2011

NASTYZEN said:
I am fortunate in that I have seen so much destructive testing in this industry to now know what works and what works not as well.

I believe they call that "experience" in the real world.

Invaluable!

38D · Oct 8, 2011

NASTYZEN said:
Where???You have to get a whole car up here.They have become scarce.

Most of the salvage yards like http://dcauto.gotdns.com/

Not sure how shipping to the great white north works

OccupantRJ · Oct 8, 2011

The link below is that of a fluxer. It goes online of your fuel hose and provides a flame with brazing flux already in it, so if the material is clean, you can just braze away! We use them at work for production applications.

http://www.gasflux.com/equipment.html

Sterff · Oct 8, 2011

I remember back in high school when I learned to braze. My teacher would give out large 1 gallon coffee cans. Then he would poke 10 or so holes in it with a large nail. We had to braze them shut and then fill it with water. If it didn't leak you got an A :lol:

. Eventually we moved on to thicker steel.

PCO6 · Oct 8, 2011

Sterff - That brings back memories! We did that too. When I was about 12 I remember watching my Dad braze a vice back together. Learning to braze was a great introduction to welding.

mrbreezeet1 · Oct 8, 2011

Do you think brass is a good choice to join the fitting to the line on a brake line that is screwed into a blow gun?
I used JB weld and it lasted about 10 years, but finally broke, so I used lead solder.
But this other one I made would not solder, so the welder used "silver solder" but must have not done it right, it did not last.
I JB welded this one, but Friday it came loose . Unless I sand it good this time and JB weld again.

OccupantRJ · Oct 8, 2011

mrbreezeet1 said:
Do you think brass is a good choice to join the fitting to the line on a brake line that is screwed into a blow gun?
I used JB weld and it lasted about 10 years, but finally broke, so I used lead solder.
But this outer one I made would not solder, so the welder used "silver solder" but must have not done it right, it did not last.
I JB welded this one, but Friday it came loose . Unless I sand it good this time and JB weld again.

Silver solder is my method of choice for making special fittings. S-200 or equiv. silver solder flux is needed for this to make a good joint, and it will make a damn good one. We silver solder hundreds of joints per week at work in a production setting. Trouble is, it's about $18 a Troy ounce these days for 1/32" :shocking:

mrbreezeet1 · Oct 8, 2011

OccupantRJ said:
Silver solder is my method of choice for making special fittings. S-200 or equiv. silver solder flux is needed for this to make a good joint, and it will make a damn good one. We silver solder hundreds of joints per week at work in a production setting. Trouble is, it's about $18 a Troy ounce these days for 1/32"

Thanks,
I'm not sure what he used, is the silver solder all the same?
I'm not sure if he used flux or not.
He is a little bit of a PITA to even talk to, He gets mad like your 2nd guessing him.
He's a pretty good welder, but I don't think he is too "High Tech" so to speak.

OccupantRJ · Oct 8, 2011

Many different types of silver solder products. Do a google search for Harris stasilv to get an idea.

dodge610 · Oct 9, 2011

Sometimes old school is still the best way to go. I used to sell the brazing rods at the weld supply I worked at we sold a ton of it to the mobile repair guys was a very good alt. to tig or mig when out in the field. no removing the part taking it back to the shop then driving back to the site to put it back on.

muibubbles · Oct 9, 2011

can someone post what material rod to use for each material? i just started hearing more about brazing at work and im interested in trying it!

muibubbles · Oct 9, 2011

bare with me as this is going to sound extremely stupid, what torch/gun/set up are you using to braze? also whats the torch called for cutting through metal? (not plasma cutter) im assuming there is a difference between the two as one is heating and the other is cutting?

sickboi55 · Oct 11, 2011

would brazing work for repairing bolt holes in cylinder heads?

metal1313 · Oct 11, 2011

muibubbles...hit up airgas in south plainfield/ piscataway. or there was a decent shop on rt1 in brunswick.

o and i'll be pming you about some of your recent purchases(trade work for beer maybe)

jhelrey · Oct 11, 2011

What is with the boi in your name^^^? Isn't that how gay guys spell boy?

fitz11 · Oct 11, 2011

Would brazing work on forged aluminium? I have a dirt bike kick lever that is broken and am looking for a way to fix it before spending the $130 on a new one.

sickboi55 · Oct 11, 2011

im not sure how "gay guys" spell boy. for me its a play on words for "sick boy" the song by social distortion and boi, the way a rap artist would spell it.

hunter1151 · Oct 11, 2011

You cannot braze aluminum...........you can weld it with a torch........or you can tig weld it. You can also mig weld it. As far as the stress that a kick starter forging is concerned, go buy a new one and be done with it.

CaseyJoes. · Oct 11, 2011

sickboi55 said:
would brazing work for repairing bolt holes in cylinder heads?

I stand corrected, see below.

fitz11 said:
Would brazing work on forged aluminium? I have a dirt bike kick lever that is broken and am looking for a way to fix it before spending the $130 on a new one.

Brazing on aluminum is possible. However, your more likely to find somebody around the corner that can do a nice strong repair using a MIG or TIG. You'll have a much harder time trying to find somebody that has what is needed to braze aluminum.

Griff93 · Oct 12, 2011

That's a cool intro to Brazing. I'm surprised you have that much trouble finding 944 struts. I had a pair that were good that I couldn't give away recently. I need to buy an acetylene bottle and then my torch rig will be complete. I bought a plasma cutter several years ago so they kinda fell to the bottom of the list. Since you like brazing, have you tried any of the silica bronze brazing rod for a TIG welder. We bought some of it recently to do some casting repairs. I haven't gotten to doing them yet but I'll take some pictures when I do. We did try it on some 14 ga 1 in sq tubing and it seemed to work pretty well.

OccupantRJ · Oct 12, 2011

Everdur is one of the silicon bronze rods, that I used to tig up up several drilled holes in the body of a 40 Ford truck I was working on. Good stuff. Haven't had the occasion to try brazing with it yet, on something like cast iron, cast steel, or forgings.

hunter1151 · Oct 12, 2011

I stand corrected............you can braze aluminum. I however cannot imagine that it would be a choice for the repair of a forged kick starter. 2XXX and 7XXX series forgings are not recomemnded for welding.

NASTYZEN · Oct 12, 2011

sickboi55 said:
would brazing work for repairing bolt holes in cylinder heads?

Absolutely.

fitz11 said:
Would brazing work on forged aluminium? I have a dirt bike kick lever that is broken and am looking for a way to fix it before spending the $130 on a new one.

I would get it tig welded if I were you.Much stronger for that application. Aluminum solder is good for Aluminum radiators and fittings to tank type applications.

Griff93 said:
have you tried any of the silica bronze brazing rod for a TIG welder ?

I hate the stuff. Very hard to fix something that was welded with it. At least in my opinion.

CaseyJoes. · Oct 12, 2011

Brazing is a suitable repair for bolt holes in cylinder heads? Is this meaning like a crack that is on the edge of a bolt hole on the outer cylinder head bolts on something like a small block chevy? I read his question incorrectly as asking if you could repair stripped out threads in an engine block of cylinder heads with brazing. I assume that would not be possible or a good repair?

Aaron8x608 · Oct 12, 2011

I have had cylinder heads with chipped bolt spot faces (iron). They heat the whole head in an oven before brazing. Uneven heating in the iron causes cracks I think.
I read in the early machine age that Silver Solder was used to hold jigs in place on high tolerance parts while being machined. After the work was done the jigs were removed with heat. It wouldn't surprise me if this technique was still being used.

Brazing 101 ,the wonder glue

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