Need info on a good oxy/acteylene set up for brazing

[verbotenwhisky]

Well today I brazed 1/8 to 1/8 6061 with just a blue bottle and got a strong bond- can't break it with a hammer, Not pretty yet but strong as hell. Also I expect to braze 5/16 SS bolt to .065 SS tube and was told blue bottle would work fine but not as fast as oxy-acet. I'll know a lot more in a few days

That looks like silver solder, not brazing and if your joining Aluminum that is what it is, the Mapp and LP gas torches will work for that and all you have to remember is put the heat to your work piece and let it melt the filler and draw it into the area to be joined.

Soldering, in particular silver solder is good and will form a good joint but you need to be aware it is weaker than a brazed joint which is a welded joint. Solder is like gluing, there isn't any penetration into the base metal, you are depending on the surface bond. Brazing will use a filler material which is similar to the material being joined (I have used metal clothes hangers to join mild steels) and require you to heat the pieces to be joined to a cherry red and the filler to the same and you melt the filler and base metal together to form the joint (penetration between the 2).

Be aware, soldering Aluminum requires the black paste flux I think.... Its been a while.....

 

[verbotenwhisky]

Oxygen and propane is good for cutting, just change the cutting tip. Cannot weld with it. Not as hot as acetylene,but a lot cheaper to use.

I use propane to braze/gas weld with, have been doing so for 40 years.... The secret with propane is to take your time and the positive is things happen a little slower giving you more time to react. with acetylene, if you are not careful you'll have a puddle in the floor.

 

[verbotenwhisky]

So it's cheaper to buy bottles on Craigslist than to refill your own? Gas is silly expensive?

I spent 27 bucks to swap bottles last time for the oxygen, the acetylene is about 35 bucks but with anticline you have to be mindful, you cannot lay the bottle on its side. a 30 pound bottle of LP (last forever through a couple Oxygen refills) and can be refilled for 20 bucks.

Look at the top ring on the bottle if you are buying used, make certain if a company name is cast into it, that the company is out of business or the collar is smooth. if you buy a bottle with Air Gas (Air Gas is still in business) on it then they will not fill it because it is a rental bottle. Lastly, if you buy second hand bottle make certain they come with the screw on tops and do not haul them without those being on the bottle. Those bottle charge to 2200 PSI and are around 100+ pounds, if you break the valve off of one it becomes a missile and will fly, it can easily kill you and at the least will do damage. Additionally if you do not have a top most welding supplies will up charge you or refuse to deal with you.

 

[helmbelly]

I am not a great welder. I can braze very good. I did for a long time.
This is a flux core weld on Stainless (don't know grade) to unknown material, that I did years ago to bring the locking screw to the front of the drill press. That lincoln welder you have , if it does dual voltage should be enough , you don't need high amperage for your task.
View attachment 467059

Nice work Woodchuck, so tell me what kind of set ups have you used for brazing and what do you like the best?

 

[skrubol]

Brazing will use a filler material which is similar to the material being joined (I have used metal clothes hangers to join mild steels) and require you to heat the pieces to be joined to a cherry red and the filler to the same and you melt the filler and base metal together to form the joint (penetration between the 2).

You're describing welding, not brazing. Brazing uses a copper alloy (generally a bronze.) Solder uses a tin alloy. Welding uses a similar alloy to what you're welding.

I use propane to braze/gas weld with, have been doing so for 40 years.... The secret with propane is to take your time and the positive is things happen a little slower giving you more time to react. with acetylene, if you are not careful you'll have a puddle in the floor.

Propane should not be used to weld steel. The welds will be brittle.

I did a cost analysis (from manufacturer recommended flow and travel rates,) of Oxy Propane and Oxy Acetylene cutting a few years ago, and given the prices in my area (Northeast US,) the cost was a wash. Propane is practically free compared to oxygen or acetylene, but propane cutting consumes more oxygen than oxy acetylene does.

On the topic of gas cylinder sizes, if you're looking at those inexpensive kits that include the torch and tiny oxy and acetylene cylinders and a carry case, those cylinders are useless unless your usage is maybe once a year. Refills (usually tank swaps) are much cheaper per CF for bigger cylinders. 40CF are the minimum size to do just about anything with and they're fairly portable. 80CF tanks can be lifted by most people. I think the last time I got compressed gas, 80CF swap was about 30% more than a 40CF swap. 120CF is often the largest tank you can purchase. Larger than that generally need to be leased.

 

[helmbelly]

I spent 27 bucks to swap bottles last time for the oxygen, the acetylene is about 35 bucks but with anticline you have to be mindful, you cannot lay the bottle on its side. a 30 pound bottle of LP (last forever through a couple Oxygen refills) and can be refilled for 20 bucks.

Thanks- great info.

 

[helmbelly]

You're describing welding, not brazing. Brazing uses a copper alloy (generally a bronze.) Solder uses a tin alloy. Welding uses a similar alloy to what you're welding.

The brazing rod specific to Alum at MacMaster is 12% silicon 88% alum, I'd guess Alum is a special case. I'm setting up for stainless steel brazing (which oxy-propane should be a good fit for) but most of my shop work is aluminum so I'd like to figure that out in parallel. I did a braze (photo posted above) with Benzomatic alum brazing rod I got on amazon. It actually worked as a test.

Is there a rod anyone has had good results with? I see Alumalloy, Muggyweld makes a Super Alloy 5, there are a couple others.

Is flux needed? I just used acetone and sandpaper.

What about terminology? People talk about brazing aluminum and the info I got from youtube vids are titled "brazing alum". But shop guys talk about silver soldering and brazing interchangeably it seems.

 

[woodchucker]

Nice work Woodchuck, so tell me what kind of set ups have you used for brazing and what do you like the best?

As I said that's a weld.
I didn't have my own rig. But I did work for a friend. He had a victor set up. Oxy/acetylene.
I would like another set up but don't have room or want the risk. I don't have room for a proper mig either.
I would do all his Brazing And cutting

 

[verbotenwhisky]

You're describing welding, not brazing. Brazing uses a copper alloy (generally a bronze.) Solder uses a tin alloy. Welding uses a similar alloy to what you're welding.

Propane should not be used to weld steel. The welds will be brittle.

I did a cost analysis (from manufacturer recommended flow and travel rates,) of Oxy Propane and Oxy Acetylene cutting a few years ago, and given the prices in my area (Northeast US,) the cost was a wash. Propane is practically free compared to oxygen or acetylene, but propane cutting consumes more oxygen than oxy acetylene does.

On the topic of gas cylinder sizes, if you're looking at those inexpensive kits that include the torch and tiny oxy and acetylene cylinders and a carry case, those cylinders are useless unless your usage is maybe once a year. Refills (usually tank swaps) are much cheaper per CF for bigger cylinders. 40CF are the minimum size to do just about anything with and they're fairly portable. 80CF tanks can be lifted by most people. I think the last time I got compressed gas, 80CF swap was about 30% more than a 40CF swap. 120CF is often the largest tank you can purchase. Larger than that generally need to be leased.

Been in the industrial gas business many years, are we talking ACF or SCF because in the business we go by ACF which is the water volume and 120ACF is a very large cylinder weighing 3 to 4 tons. the problem with SCF is it varies with pressure and gas type.

My favorite gas joke if how much, by weight, helium does an 8 tube trailer hold at 3000 PSI (context, the tubes are around 60 ACF 34'-0" long and 24" diameter) and the answer is 2100 pounds of helium.

I am not attempting to be a smart a$$ here, I am attempting to make a point, when we throw these terms around they are not always as they seem.

Welding is, or at least use to be, defined as fusing 2 base materials together with the use of a filler material while soldering was defined as a bonding process where the base material is not fused with anything but rather bonded by heat and a thin layer of filler material.

I have never had an issue with brittleness using LP, it is very simple to anneal the material, I am after all holding a very hot flame on the end of the torch in my hand.

 

[strantor]

Been in the industrial gas business many years

It has always been my understanding that the difference between welding, brazing, and soldering is as follows:

Welding: The two base metals are melted together, with or without (almost always with) a filler metal. Usually the base metals and the filler are similar, but not always. The key is the actual mixing of metals.

Soldering: two base metals are not melted or mixed. A dissimilar filler metal with a lower melting temperature is flowed into the joint and the base metals are surface bonded.

Brazing: basically the same as Soldering but with a filler having a higher temperature melting point and closer to the same properties as that base metals. But there is still no melting or mixing of the base metals.

I did not realize these terms might mean something different to others.