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  1. #1
    Join Date
    Aug 2010
    Location
    Swamp land
    Posts
    28

    Hmm 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.

  2. #2
    Join Date
    Aug 2010
    Location
    Swamp land
    Posts
    28
    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.

  3. #3
    Join Date
    Apr 2007
    Location
    Kaufman county, Texas
    Posts
    10,493
    I prefer turbo torch, 15%, fiberglass cloth[the one with the little squares in it], and wet rags. -
    "You boys are really making this thing harder than it has to be". Me

    "I say we just nuke them from space, that is the only way to be sure". Winch from ALIENS, forgot her name.

    Service calls submitted after 3PM will be posted the next business day.

    I give free estimates [Wild Ass Guesses] over the phone.

    My front door is locked. For your personal protection.

  4. #4
    Join Date
    Aug 2010
    Location
    Gadsden, AL
    Posts
    21
    Quote Originally Posted by do over View Post
    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.
    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

  5. #5
    Join Date
    Apr 2010
    Posts
    34
    Do Over, you sound like a perfectionist, not a bad thing.

  6. #6
    Join Date
    Aug 2010
    Location
    east columbus ohio area
    Posts
    15
    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.

  7. #7
    Join Date
    Feb 2007
    Location
    Corpus Christi, TX
    Posts
    1,773
    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)
    Testing....Signature on Full Site Forum

  8. #8
    Join Date
    Mar 2007
    Location
    Madison, Wisconsin
    Posts
    2,263
    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?
    I r the king of the world!...or at least I get to stand on the roof and look down on the rest of yall

  9. #9
    Join Date
    May 2010
    Location
    Thurmont, Maryland
    Posts
    50
    Quote Originally Posted by TCreacy View Post
    Now for a bonus question: What does the Acetylene B and MC tanks sizes actually mean. (Where did the lettering standard come from)
    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

  10. #10
    Join Date
    Jan 2010
    Posts
    6,790
    Quote Originally Posted by Thurmont HVAC View Post
    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
    Very interesting.

  11. #11
    Join Date
    Feb 2007
    Location
    Corpus Christi, TX
    Posts
    1,773
    Quote Originally Posted by Thurmont HVAC View Post
    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
    MC = Motor Coach (cars)
    B = Buses
    Youre right on...
    Testing....Signature on Full Site Forum

  12. #12
    Join Date
    Jun 2005
    Location
    Near Chicago, IL
    Posts
    3,317
    MC= Motor Car

  13. #13
    Join Date
    Feb 2004
    Location
    Midwest
    Posts
    9,937
    What's pipe diameter limit for a straight acetylene turbo torch using 15%?

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