Brazing line set

I would like to see what people are using to do there line sets. I think it would be fun to see the see how different we are to do the same job.

I use the cheep green pads to clean the copper. They leave no residue.
Stay-sil 15% brazing rods.
Oxygen acetylene torch
#3 tip < 5/8”
#7 tip > 5/8”
Purge line with Argon (not nitrogen)
Thermal Engineering analog Vacuum Gauge.
Robinair 5 cfm Vacuum Pump.
Wet rags as heat shield.
Ratcheting Tube Bender you know the ones you need to keep repositioning on the larger tubing or you will kink the tubing.

I learned the trade at Columbus technical collage back in 74-76. That was a long time ago, I remember the instructor telling us then that there was a new gas out called MAPP, he told us never to use MAPP gas because it didn’t have the heat needed to do the job right. Back then we were thought brazing using an air acetylene torch with a B tank. I can’t remember the name of it but it looked like a turbo torch. All I can think of is we cooked a lot of copper back then. This is my thought on MAPP gas because that what I learned. I also don’t think air acetylene witch I learned on is not a good choice for a torch anymore. But then maybe it's as I was told once, it's not the torch, it all in knowing how to use the torch.

I prefer turbo torch, 15%, fiberglass cloth[the one with the little squares in it], and wet rags. -

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Originally Posted by do over

I learned the trade at Columbus technical collage back in 74-76. That was a long time ago, I remember the instructor telling us then that there was a new gas out called MAPP, he told us never to use MAPP gas because it didn’t have the heat needed to do the job right. Back then we were thought brazing using an air acetylene torch with a B tank. I can’t remember the name of it but it looked like a turbo torch. All I can think of is we cooked a lot of copper back then. This is my thought on MAPP gas because that what I learned. I also don’t think air acetylene witch I learned on is not a good choice for a torch anymore. But then maybe it's as I was told once, it's not the torch, it all in knowing how to use the torch.

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the instructor i have now says mapp gas will work, but not propane. i haven't tried it yet, but have been using oxy-acetylene torches

Do Over, you sound like a perfectionist, not a bad thing.

brazing with mapp gas is good for about 3\8, 1\2 inch max copper, if its close to any larger masses of metal, you gotta get out the oxy acetyl. it is convienent for repairing hairline condensor cracks on rooftops, just easier and lighter to carry.

Brazing is done at tempertaures around 1200-1800*F
Soldering is done around 500-800*F

Brazing Should always be used with refrigerant and anyother highpressure piping, it brings the copper to a hotter state and allows the filler material to bond with the molecules

Soldering is done a low temps and basically all you melt is the solder, and it will only adhere to the surface of the copper.

I cant find the exact temperatures online, but I havent know an Air-Acetylene rig or Air-Mapp rig to get hot enought to properly braze.

Now for a bonus question: What does the Acetylene B and MC tanks sizes actually mean. (Where did the lettering standard come from)

I use Oxy Acetylene for most jobs, but have my handy Turbo for back up, or jobs with a lot of joints. 15% wet rags, abrasive cloth.

Buddy of mine does all resi stuff, and always solders his line sets, been doing it for many years and never had a joint leak after initial test. Uses a hand MAAP torch, hard to argue with his results. And he has never burnt a valve or TEV.

I use Nitro like most, is Argon cheaper?

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Originally Posted by TCreacy

Now for a bonus question: What does the Acetylene B and MC tanks sizes actually mean. (Where did the lettering standard come from)

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I was taught that the tank designation was from the old days, MC Meant for Motor cycle use, as in the Head light, yes bottled gas was used for lighting, and the B tank was for use for bus head lights. not sure if it is 100% correct, but thats what our instructors taught us in trade school in the 80's

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Originally Posted by Thurmont HVAC

I was taught that the tank designation was from the old days, MC Meant for Motor cycle use, as in the Head light, yes bottled gas was used for lighting, and the B tank was for use for bus head lights. not sure if it is 100% correct, but thats what our instructors taught us in trade school in the 80's

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Very interesting.

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Originally Posted by Thurmont HVAC

I was taught that the tank designation was from the old days, MC Meant for Motor cycle use, as in the Head light, yes bottled gas was used for lighting, and the B tank was for use for bus head lights. not sure if it is 100% correct, but thats what our instructors taught us in trade school in the 80's

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MC = Motor Coach (cars)
B = Buses
Youre right on...

MC= Motor Car

What's pipe diameter limit for a straight acetylene turbo torch using 15%?