Miller Electric

Welding Discussion Forums

Home » Resources » Communities » Welding Discussion Forums
 
Miller Welding Discussion Forums - Powered by vBulletin

Page 1 of 7 123456 ... LastLast
Results 1 to 10 of 67
  1. #1
    Join Date
    Mar 2006
    Location
    Queens NY
    Posts
    1,547

    Default How do you sweat AC copper tubing?

    I have an ac install to do but i don't know what to use to sweat the copper lines together. I have heard people say that you shouldn't solder them, you should braze them, but no one can tell me what kind of brazing/flux to use. Do you guys know?
    Dynasty 200 DX
    Millermatic 175
    Spectrum 375
    All kinds of Smith OA gear

  2. #2
    Join Date
    Sep 2005
    Location
    16919 Pole Rd. Brethren, MI 49619
    Posts
    4,395

    Default

    I know a couple of my buds have been using common lead free, seems to work. Most common though is something like silver 45 and white flux for silver.

  3. #3
    Join Date
    Feb 2007
    Location
    Ukiah, Ca
    Posts
    280

    Default

    Use 430 degree soft solder, w/acid liquid or paste flux. Clean well, use flame. Flux & solder should be available at LWS or home store.
    AutoArc 230 (MM 210)
    3035 spoolgun
    Spectrum 625
    Dialarc HF w/Coolmate 4

  4. #4
    Join Date
    Aug 2006
    Location
    Plainview, TX
    Posts
    334

    Default Don't forget the emory cloth

    My dad showed me this and it has worked every time. We use a small piece of emery cloth to clean and polish the end of the copper line before applying the flux and lead free solder. You can roll a small piece to clean the inside of the fitting being attached too. You can just preheat the fitting a tad before applying the flux so that it will flow evenly over the joint before mating. It doesn't take much at all. Had to do some work on the refrigerator water line the other day to replace some parts of dissimilar metal that had grown shut with rust. Properly cleaned ends with proper flux and lead free solder should do the trick. The label directions on the flux and solder can be helpful too. Also, a good acetylene torch works well too. NOT O/A just acetylene. Be sure to look in the plumbing department at your local hardware store or big box store.
    '77 Miller Bluestar 2E on current service truck
    '99 Miller Bobcat 225NT for New Service Truck
    '85 Millermatic 200 in Shop

    '72 Marquete 295 AC cracker box in Shop
    '07 Hypertherm Powermax 1000 G3 Plasma Cutter in Shop
    Miller Elite and Digital Elite Hoods

  5. #5
    Join Date
    Dec 2006
    Location
    Alaska
    Posts
    732

    Default

    careful with the flux too much left in the joint and it will eat the copper from the inside out.
    It only takes a whisper thin amount I used an empty jar of flux for two weeks just using what had soaked into the brush.

    Put the flame on one side and the solder on the other when the solder starts to melt remove the heat stroke the solder around the joint once. let it set up for a minute then take a damp rag and wipe the joint and remove all excess flux.


    Tj
    TJ______________________________________

  6. #6
    Join Date
    Aug 2004
    Location
    Milan Michigan
    Posts
    1,725

    Default

    SBerry is right,
    Dont use ordinary solder that you use on copper water pipes- that is solering.

    I use Silver solder which melts at a higher temputure, you want a 45% silver content and yes the flux I use is a white paste, when flux turns clear add the filler.
    The silver solder is a stronger joint and will stand up to the vibration of the compressor.
    And of course clean it before hand.

    When you silver solder you will need an oxy/ acyt. torch with a very small tip.

  7. #7
    Join Date
    May 2005
    Posts
    600

    Default

    Quote Originally Posted by Portable Welder View Post
    When you silver solder you will need an oxy/ acyt. torch with a very small tip.
    i agree with Flukecej, no O/A till you're proficient, use a air/acetylene or a MAPP torch, the O/A can melt the Cu tube way fast and in a hurry if you aren't watching.

  8. #8
    Join Date
    Aug 2006
    Location
    Raymore Missouri
    Posts
    1,920

    Default

    If you were licensed to do the work, you would already know.....but if you insist, you can use Silfos 6% sticks that may be purchaced separately sometimes, cheapest, or 45% silver solder with flux. When it comes to charging the system, get a licensed guy or pay the fine if you get caught. Nick...HVAC tech .....since 1971
    Nick
    Miller 252 Mig
    Miller Cricket XL
    Millermatic 150 Mig
    Miller Syncrowave 200 Tig
    2-O/A outfits
    Jet Lathe and Mill
    Jet 7x12 horz/vert band saw
    DeWalt Multi Cutter metal saw
    Century 50 Amp Plasma Cutter
    20 ton electric/hydraulic vertical press
    Propane Forge
    60" X 60" router/plasma table

    www.youtube.com/watch?v=jTu7wicVCmQ
    Vist my site: www.nixstuff.com
    and check out some of my ironwork and other stuff

  9. #9
    Join Date
    Mar 2006
    Location
    Queens NY
    Posts
    1,547

    Wink

    thanks for the replies.

    I know your not supposed to use solder and flux (water pipe stuff) since it can contaminate the freon and damage the compressor.

    Most sites reccommend brazing, but with what exactly i do not know.

    I've heard silfos before and will look for it.

    Unit is precharged, all i have to do is connect the lines and purge (according to the directions).

    Get a licensed AC guy?? Come on, i've been working on auto ac stuff for 18 years, airplanes, computers, SANs, networks, houses, Welding, engines .................................................. .................................................. ........ etc. etc. etc.
    I don't have a license for any of it!!!! (except the airplanes!)
    Dynasty 200 DX
    Millermatic 175
    Spectrum 375
    All kinds of Smith OA gear

  10. #10
    Join Date
    Aug 2006
    Location
    Raymore Missouri
    Posts
    1,920

    Default

    OK, so now you solder the lines to the ac unit and evaporator coil. Now are your solder joints leaking? Well after you release the charge to the lines, I guess you'll find out. If not, great. What if they are, then what will you do?
    You can't resolder the lines with pressure in them. Now you'll have to capture the refrigerant somehow and redo the leaks. I hope you leak test the next time but with what? I use nitrogen which can be vented to the atmosphere
    legally. If no leaks I evacuate the system with a pump, release the charge and check for correct amount refrigerant depending on the coil size, length and size of lines. Some units may be undercharged at the factory. Are you using the freon to leak lest and then purging, which lowers the charge amount. By the way, have you installed the correct size filter drier in the
    liquid line? Good luck with your install.
    Nick
    Miller 252 Mig
    Miller Cricket XL
    Millermatic 150 Mig
    Miller Syncrowave 200 Tig
    2-O/A outfits
    Jet Lathe and Mill
    Jet 7x12 horz/vert band saw
    DeWalt Multi Cutter metal saw
    Century 50 Amp Plasma Cutter
    20 ton electric/hydraulic vertical press
    Propane Forge
    60" X 60" router/plasma table

    www.youtube.com/watch?v=jTu7wicVCmQ
    Vist my site: www.nixstuff.com
    and check out some of my ironwork and other stuff

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Warning: Function split() is deprecated in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/footer.inc.php on line 82

Welding Projects

Special Offers: See the latest Miller deals and promotions.