Brazing and soldering aluminum

[Kern Dog]

I know that when something works and holds together, it pisses off the eggheads that claim that it wasn't done right.
Sometimes it takes higher education to make a man lose his common sense and civility.

 

[zyzzyx]

1. Flame Temperature: Both these gases are combined with oxygen to create the desired profile suitable for welding different types of metals. Propane, also referred to as LP gas or Liquefied Petroleum Gas, when mixed with oxygen generates a flame temperature of 2800 degree Celsius. However, acetylene on mixing with oxygen generates a flame temperature of 3100 degree Celsius. High flame temperature and excellent flame impingement characteristics of acetylene are being exploited for welding or cutting the rounded edges of any metal. The hotter flame temperature will allow quick piercing of tough materials.
2. Thermal Output: Acetylene and propane are also differentiated based on their thermal outputs. The British Thermal Unit (BTU) value of acetylene is 1470 per cubic feet, whereas propane has a BTU value of 2498 per cubic feet. Even if acetylene has a higher flame temperature than propane it doesn’t mean that the latter produces any less heat. Although oxy acetylene combination assures a faster preheating than propane, most of the preheating in welding is performed with propane-oxygen. This is because propane is cheaper and capable of producing a high amount of heat necessary for pre-heat.
3. Welding Process: Firstly: Propane gas cannot be used for gas welding. When acetylene burns in oxygen, it creates a reducing zone that cleans the steel surface. Propane does not have a reducing zone like acetylene and hence cannot be used for welding.

 

[zyzzyx]

And, I stand corrected about "Soldering aluminum! Yes, you can solder aluminum with a Zinc/Aluminum filler rod but the quality of the weld is not good.
There is no penetration. I never had any experience with that type of filler rod.

 

[RemCharger]

Certainly lots of different angles on this debate..
If a flat rate technician adhered to the published service instructions on most jobs, he'd be paying the bank to take his house back.
Now on the other hand..
I had a customer wanting to " get into cars". So he got a Satellite, got a 440 etc etc.
Decided he needed a big Jesus oil pan. Then found that the pickup was too short. So he strapped on his thinking cap( computer guy), went and purchased a cheap gasless mig welder and set out to lengthen it.
It ended up coming to me with spun rod bearings. Upon pan removal, I see that he had welded a piece of house plumbing copper pipe to the steel pickup. Could it be done? Yes. Did it work? No.
When I first saw brazing aluminum, it reminded me of this story

 

[Fran Blacker]

Talk about original MAPP gas is mute, it's not available. This article explains why, a little long but you can read what you want. MAPP Gas Discontinued: What Happened and Why? (+FAQs)

 

[RJRENTON]

Aluminum can certainly be soldered, ask any farmer with aluminum irrigation piping.

Soldered with what?? Big difference in high pressure refrigerant tubing and 1-2 psi irrigation piping......so what if it leaks a little......probably could use GORILLA glue....or the stuff the guy on TV uses to build a boat.....
BOB RENTON

 

[Kern Dog]

I do understand that a man with a little knowledge and skill is capable of creating more problems than he solves.
I am in no way advocating using aspirin to cure cancer here.
The intent is to fuse aluminum tubing together to allow for custom shapes and lengths that are not available off the shelf. I do like the idea of re-flaring an end as opposed to this. Several members have suggested it and it is worth considering. I am absolutely open to any reference or link anyone might have on the tools needed to do that.
I already had nozzles, gas canisters and wire brushes to clean things here, the only thing that I needed in regards to materials was the filler rods which were easily found at the welding supply store. I have not given up on the idea. I only gave serious consideration to try this 2 weeks ago when I was at an A/C shop and a tech offered to gas weld/solder a line that was about 5" longer than we needed. The finished job looked almost undisturbed and it got me thinking. I recalled the FBBO member that I quoted in post #28. He responded here in #30. His first effort worked and is still working. What one man can do, another man can do.
Oh, here is a tip:
If you think that someone like me is stepping out of bounds and is wasting their time, the dumbest thing you can do is tell them it will never work.
Input like that is not taken as guidance, it is taken as an insult and a challenge.

 

[Kern Dog]

Not exactly cheap...

 

[1 Wild R/T]

Another way of getting custom lines is to drop the aluminum & use steel... The original A/C lines on these cars were steel... Steel can be welded or silver soldered... It would require sourcing steel fittings, I have sourced plenty, they are available...

 

[Tony Tee]

You can mig weld aluminum as well. I used to work for a glass / storefront company and I was a aluminum mig welding fool. You just have to have the right equipment. We used a Teflon liner for the aluminum mig wire. But a spool.gun would have been better. The trick was to keep the mig lead as straight as possible. Just my $.02

 

[ckessel]

Not exactly cheap...

View attachment 1697778View attachment 1697774

I gots one of those too.

 

[Photon440]

Soldered with what?? Big difference in high pressure refrigerant tubing and 1-2 psi irrigation piping......so what if it leaks a little......probably could use GORILLA glue....or the stuff the guy on TV uses to build a boat.....
BOB RENTON

Soldered with aluminum solder of course, as this thread is about aluminum piping. I've soldered aluminum piping on a car A/C system before to patch a hole that had rubbed through. It's not all high pressure, the low pressure side is only 25-45 psi. Conversely, irrigation systems can run over 100 psi. which you'll need to spray a 250 foot radius circle. So what if it leaks a little? Leaks are the bane of farmers, they reduce available water pressure and quantity and may flood unwanted areas.

 

[Geoff 2]

I have both soldered & brazed alum. Both can be done. I have a roll of 16g alum solder, much like the solder you use for soldering copper wire.

 

[Kern Dog]

Soldered with aluminum solder of course, as this thread is about aluminum piping. I've soldered aluminum piping on a car A/C system before to patch a hole that had rubbed through. It's not all high pressure, the low pressure side is only 25-45 psi. Conversely, irrigation systems can run over 100 psi. which you'll need to spray a 250 foot radius circle. So what if it leaks a little? Leaks are the bane of farmers, they reduce available water pressure and quantity and may flood unwanted areas.

I have both soldered & brazed alum. Both can be done. I have a roll of 16g alum solder, much like the solder you use for soldering copper wire.

Thanks for adding some actual real world experience to the topic. I'd be apt to trust a guy that has done things instead of a guy that theorizes and professes that it isn't the right way to do it.
I had a neighbor years ago that seemed to be a car guy. He had a Mini Cooper in 1000 pieces the whole time he lived across from me. I would tow in a wreck and have it painted, running and driving in a few months, then sell it.....all the while his Cooper would sit untouched while he plotted and planned on what to do. He was an "engineer" that was compelled to overthink everything. While guys like him plan and plan to get it right, other guys jump in and get it done.

 

[Lefty71]

piping......so what if it leaks a little......probably could use GORILLA glue....or the stuff the guy on TV uses to build a boat.....
BOB RENTON

See what i mean Bob??? Now you're looking down your nose at farmers. Maybe chill??

 

[QuickBpBp]

I understand why you want to move it and make it cleaner looking. Coming from a farming background we had machinery that had hundreds of feet of hydraulic lines, rubber hoses along with 30-40 feet of A/C lines. The pic below is the grape harvestor which was what I ran. 100% hydraulic, raised in the front, the back and side to side to stay level and powered by hydraulic motors. Also all fans, shakers, rollers and tanks were hydraulic motors too. I have lots of experience with repairing and replacing lines. I think a compression fitting on the end would be easy and clean as it looks like there is a union to that line already. Good luck with whatever you decide.

 

[Kern Dog]

Here is the flare that looks hard to do.

It looks like a ridge added to the tubing itself but using a pinpoint light, I looked inside and saw that it has a groove. This shape is formed by compressing the line using a bubble shaped die of some type.
The female end…

There are three distinctive sections that get reshaped.

The very end where the fitting presses against…

The second area where the raised rib on the other line gets seated…

The third part of the flare is just a widening of the line…

This makes room for this part of the other line.

Even this line isn’t a perfect shape.

The raised sections that were reshaped are out of square and slightly crooked. It may have still sealed fine but this was professionally done by Classic Auto Air.
My goal is to do this as good or better.

 

[RJRENTON]

Here is the flare that looks hard to do.

View attachment 1698309


View attachment 1698310

It looks like a ridge added to the tubing itself but using a pinpoint light, I looked inside and saw that it has a groove. This shape is formed by compressing the line using a bubble shaped die of some type.
The female end…

View attachment 1698313

There are three distinctive sections that get reshaped.

The very end where the fitting presses against…

View attachment 1698314

View attachment 1698315

The second area where the raised rib on the other line gets seated…

View attachment 1698316

The third part of the flare is just a widening of the line…

View attachment 1698318

This makes room for this part of the other line.

View attachment 1698321

Even this line isn’t a perfect shape.

View attachment 1698323

The raised sections that were reshaped are out of square and slightly crooked. It may have still sealed fine but this was professionally done by Classic Auto Air.
My goal is to do this as good or better.

The #1, 2 and 4 pix are SAE O-ring fittings the pix with the Phillips head screw driver pointing are not flare fittings neither male inverted flare or female flare fittings. Where is the nut that joins the pipe/tubing ....it appears to be neither an SAE/JIC connection and what you show appears to be furnace brazed (under a controlled atmosphere) not TIG, MIG, BRAZED OR SOLDERED.......just my opinion....
BOB RENTON

 

[Kern Dog]

I continue to be disappointed by these tanks and nozzles.

Two of them have igniters.

I get inconsistent action from these things. Most times, they don’t light without outside help from one of these:

Even so, most of the time once I cut the flame from the candle lighter, the propane or Map/Pro gas flame stops.
When the flame does actually stay going, sometimes it dies out once I tilt the canister. Sometimes it just burns a yellowish flame which is of course a lower temperature. This is bullshit. Some of this stuff here is old, some is new. Some cans are close to being empty, a couple are new and heavier. It pisses me off that I can’t get a steady blue flame going. Nobody has an explanation as to why the flame stops.

Secondly…
How do you hold the two pieces your trying to solder together?
A metal vise seems to want to pull heat from the tubes. A wooden block just wants to burn.

The above picture was for demonstration purposes. The orange pads are rubber and would melt with the heat.

 

[Photon440]

Kern Dog, you need one of these to screw into your gas bottles.
www.ebay.com/itm/BISupply-Hand-Held-Propane-Torch-Kit-50in-Handheld-Torch-with-Hose-and-Burners/353196856697

Your wooden block could work, but cut out the area around the joint. Then the wood won't burn, and you can get to all sides of it. Also, I would sleeve that joint with a larger piece of tubing, after the initial joint is finished and filed smooth.