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Brazing - How to

Norman, you should have mail in a couple of days...

Be on the lookout!


  • This may have been ask before,.. sorry if its a repeat.

    I am just learning A/C and was told not to solder refrigerant lines, but to braze them instead. Is that correct and if so, does anyone know of a good tutorial on the websomewhere?

    I picked up some brazing rod and have been trying ot teach myself but im not having much success.

    Thanks in advance!

    - Norm

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  • Charles G.
    Charles G. Member Posts: 113

    It's so easy when you know how...Go to "ASK.COM" and type in "Brazing". See where that takes you. Lots of other sources. Harris is a brand of solder/brazing materials; I'm sure they have a web site. That's the beauty of the computer age--no one should plead ignorance anymore. There's no question that you can't find an answer to.

  • Im the hands on type,.. I need to find someone to show me how its done, this learning on my own thing has me burning all kinds of holes in the copper. I'll see if I cant find a welding shop that wouldnt mind giving a lesson.

    Thanks for the help

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  • Brad White_101
    Brad White_101 Member Posts: 12
    Sounds like....

    A topic for a video!
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380

    Very Interesting...
  • Mikey B
    Mikey B Member Posts: 9

    The key that i find in brazing is having a great tourch. you have to get the copper hot enough to have braze flow. Be careful when doing the condensor not to get the service valves to hot and melt te gaskets. i keep a wet rag on them for excessive heat. Good luck and practice.
  • Tony_23
    Tony_23 Member Posts: 1,033
    Are you using

    Oxy-Acetylene ?

    Get an Air-Acetylene or back off the O2 a bit. Sounds like too much concentration in one spot, for too long.

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  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Oxy-A or MAPP?

    I am interested too. Most guys I see doing at least silver soldering use MAPP. Those that do brazing I see using either one 50-50 percent of the time. Seems to be preference or maybe the size of the pipe they are working on. Curious what you think, Tony.
  • Plumdog_2
    Plumdog_2 Member Posts: 873

    The term "brazing" may be what's messing up your efforts. If you try brazing rod as used with steel it won't work worth poop. Get some Sil-Phos or Silver solder type rod for copper. It is usually square or flat and works well without the need for oxy (except large diameters). You will need acetelyne turbo-torch, however.
  • Techman
    Techman Member Posts: 2,144

    Hi All!This is for regular ACR work .Soldering is 700*F-800*F and lower ,Brazing is higher,1100*F -1500*F.The hard long sticks come in 4-5 different silver percentages from 0-15%silver.The Phos in the sticks is a built-in flux. 45-50% is used sometimes but, this is for "regular" stuff ,1 1/8"suction and lower.MAPP is good for any place where is no wind,takes to long to heat up ,Turbo a little faster.OxyAcete does the job better, I think.The flame should be seen and just heard,for the most part.Every thing gets cleaned ,even the 4 sides of the braze stick.The torch is in constant motion,from tube to fitting to tube .Its the heat of the copper that melts the rod ,not the heat from the flame. When the rod starts to flow ,all, of the heat goes to the fitting. Try it on a piece of scrap copper.Enjoy your Day!
  • Tony_23
    Tony_23 Member Posts: 1,033
    I use

    Air-Acetylene, almost exclusively. TurboTorch, B-tank, up to a 14 tip. Use it for silver, bronze, AND 95/5 soft. Very quick, rosebud-ish flame. MAPP is light duty in my book, I use it in my hand torch for lighting pilots :)

    Oxy-Acetylene is only needed for brazing steel (not small dia. steel tubing) where the heat needs to be concentrated just to get the material up to temp at "the puddle", but not much beyond.

    Talking about all this has got me longing for the "shop" my Grandfather taught me in as a boy. He would give me the repair projects brought to him that I could handle, and no one knew the difference. God rest his soul.

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  • Weezbo
    Weezbo Member Posts: 6,232

    i am a clean freak so i braze and after it cools down i clean everything.... inspectors and other watcher ons often cant believe that i used silver :) or that the work isn't all burned ugly colours....

    to me the thing is Clean everything ....Dial the heat so it(the work piece) is cherry. shoot the silver to it...

    a cool rag is good and a damp rag for keeping parts and pieces from getting hot. :)

    remember...Dirt is the enemy :)

    mapp gass& Oxy is my small torch....
    it uses two small canisters and can cut 3/16th's stainless.
  • S Ebels
    S Ebels Member Posts: 2,322
    Hard to say what's happening but...........

    If you're perforating the pipe it's simply a matter of too much heat.

    Step #1 is to get a torch set along with the correctly sized tips for the pipe diameters we normally see in A/C work. These would be 1 1/8" and down. The tips you should be using will be from a #1-#3 size and these are brazing tips not cutting tips. Harris and Victor both make nice portable kits made for A/CR work. If you have this equipment and are using the right sized tip I would guess you're running the pressure too high. I usually set the O2 regulator at around 10# and the acetylene at less than 5# with a number 2 tip. Light off your acetylene and set your regulator for a fairly large (6-10" long) yellow flame, then open up your O2 and bring the flame in tighter to the torch tip. You'll see a small, tight, light blue flame surrounded by a bluish yellow outer flame. From there play with your throttling valves on the torch head to get the size flame you want and that's appropriate for the work at hand.

    Get yourself some good brazing material. (it ain't cheap) As a rule of thumb the higher the % silver content the easier it is to work with and the more expensive. Get a few pieces of scrap copper, which doesn't have to be A/CR tube, and stick em together. You'll find that as you're brazing you'll see the material flow on the outside of the fitting. Where it flows on the outside, it's also flowing on the inside. Nothing will help you more than practice and using as little heat as possible.

    PS: When you're brazing around the valves on the condensing unit, it's a good idea to wrap them with a wet rag to prevent burning the seats.
  • hr
    hr Member Posts: 6,106
    Welding Supply storesl

    will often have seminars and hands on demos. Usually the staff will be glad to do a one on one demo of a certain product or piece of equipment.

    If not find the local area rep for Harris or other brands of silver solder products. They may even stop by your shop to demo a product if they are in your area.

    Harris always has hands on demos at trade shows. Check into their newest "Blockade" solder product. Very easy to learn.

    hot rod

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  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380

    An absolutely awesome product.

    Funny thing though... Most of the techs I speak to in the NY area have never even heard of it... I swear by it!
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380

    I didn't forget about you... I'll be out at the office next Tuesday!
  • JackEnnisMartin
    JackEnnisMartin Member Posts: 70

    Why has no one taught you how to sifoss that is the industry standard for copper piping in the HVAC trade. Brazing if you mean prefluxed brass rod is not a common way to join copper piping. In the event you are brazing copper to steel use a good silver soldering flux pretin the area with silver solder and then fill with fifteen percent silfoss. You can solder refrigeration lines if you wish use staybright silver bearing solder it is rated at 26,000 psig and flows at 400 degrees F. In the jobs where the high heat required for silfoss is impossible to use staybright gives you a real choice. I started out in the ammonia trade and luckly I have been arc welding since I was thirteen -- forty two years ago as I had to learn to weld pipe as part of the installation process.
    - Hope this helps and all the best - stay in the trade up hear in Winnipeg trades people are so short you can name your own price -- money is to be made!!!

    Jack Ennis Martin
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380

    StaBrite and other low temperature, silver bearing solders are on their way out for use in air conditioning installation work. Forgetting about the higher pressures of R-410a, for example, many local codes are prohibiting the use of these materials because they can facilitate the release of refrigerant in the event of a fire. Since the temperature of the flames can excess the melting point of these materials, firefighters have been exposed to toxic fumes as a result of refrigerant releases.
  • Arthur
    Arthur Member Posts: 216
    Silfossing refrigeration tubing.

    What every one has forgotten to say is when you really do get the hang of it don't forget to have nitogen flowing though the tubing as you silfos it to stop oxydisation of the inside of the pipe, compressors don't like flakes of that stuff.
    Remember with silfos the pipe melts the rod NOT the flame the flame heats the pipe not the rod.
  • rick_45
    rick_45 Member Posts: 13

    harvey ,explain how you braze and we will help .clean pipe good torch ,I use mapp gas and the air actelene.
  • Weezbo
    Weezbo Member Posts: 6,232
    i just thought of something cool*~/:)

    there is a video selection on the menu.

    maybe one of us can braze up some 5/8th,s and a dab of2".

    my electric camera has a video feature however it doesnt go long.... 2" takes lots of heat... what you are brazing also has some bearing on How To .

    and the outside air temp...brazing in a ditch when it is cold outside is a particular skill...
  • Empire_2
    Empire_2 Member Posts: 2,343
    15% SilFos

    I like it and use it exclusively EXCEPT when soldering near an expansion valve, or reversing valve. I usually run 1/2psi to 1 1/2 psi through depending on the size of the copper tubing. Just a note, in case the first questionnaire did not know, the Nitrogen runs through and exits out an open point in the piping you are working on.
    ;-) By no means is the line pressurized. I too am surprised that this was not taught in the training school.....

    Eugene, I did see a video on this topic once and I'll try to find it again. There has to be at least a few out there.

    Mike T.
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Working on a new one

    A new one is in the making... Stay tuned... I Hope...
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Pressurized lines

    Great point Mike...

    You should NEVER solder or braze pressurized lines!

    They can absolutely ruin an otherwise perfect day.
  • scotty_3
    scotty_3 Member Posts: 6

    try stay silv 15 and get the pipe red hot also run a trickle of dry nitrogen through the pipe as to not get all that black stuff on the inside of the pipe....i usually just tape my yellow hose to one end of the pipe and just trickle a tiny bit in the tube very important with a 410A system
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