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I can’t solder lead-free brass fittings

newtonkid88
newtonkid88 Member Posts: 100
edited August 21 in Plumbing
I’ve been soldering off and on for over 10 years from copper pipes that hold 150 psi compressed air to electronic circuit boards.
So I’m not a complete idiot. But I’m stumped.

Now, I’m trying to do my baseboard radiators. I’m trying to connect 3/4” baseboard copper pipe to 1/2” Uponor pex. I need a straight fitting.

https://www.supplyhouse.com/Uponor-Wirsbo-LF4515075-1-2-ProPEX-x-3-4-Female-Sweat-Copper-Pipe-Adapter-Lead-Free-Brass

The only fitting I see available is 1/2” Propex x 3/4” Female Sweat. Available from Uponor or Sioux Chief. Only in lead-free brass.

I’ve tried No 95 tinning flux. I’ve tried regular water soluble flux that I normally use. The solder just beads on the brass fitting like water on a freshly waxed car. 

I’ve watched youtube videos on soldering lead-free brass but it just doesnt work for me.

Comments

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,449
    edited August 21
    I won't ask whether you're cleaning the fitting and pipe until they shine and all oxidation has been removed because you know that already. It's either the flux or the solder unless you're overheating the metal. That thin copper that's used for BB gets hot really fast. What kind of torch are you using?
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
  • newtonkid88
    newtonkid88 Member Posts: 100
    edited August 21

    I won't ask whether you're cleaning the fitting and pipe until they shine and all oxidation has been removed because you know that already. It's either the flux or the solder unless you're overheating the metal. That thin copper that's used for BB gets hot really fast. What kind of torch are you using?

    Yes I clean them really well. I even got the idea to try using isoproyl alcohol to completely remove any oils or contaminants.

    The metals do change color but I keep on probing the 95/5 solder until it melts. So I have no choice. I remove the heat when the solder melts. I am using a propane torch. I've tried it on really low heat, and also medium heat.

    All of my copper to copper joints and copper to regular brass joints look amazing. The solder flows and sticks like it's supposed to.
  • mattmia2
    mattmia2 Member Posts: 6,713
    I buy npt propex fittings then use a copper npt adapter not so much because the brass won't wet but because if i screw up sweating it to the point i can't clean it up and try again i'm out like $10.
    PC7060
  • newtonkid88
    newtonkid88 Member Posts: 100
    mattmia2 said:

    I buy npt propex fittings then use a copper npt adapter not so much because the brass won't wet but because if i screw up sweating it to the point i can't clean it up and try again i'm out like $10.

    GENIUS! Thank you
  • newtonkid88
    newtonkid88 Member Posts: 100

    95/5 is a PITA. I don't like it. Use "NOKRODE" flux (there tinning flux is better). Don't overheat it and use "Silvabrite solder. Maybe your flux is bad.

    The problem with 95/5 is that it is solid and liquid at the same temperature....no in between. Look it up. Silvabrite has a liquid temp and a solid temp that are a few degrees apart, so it is mushy in between and fills better.

    All of my copper to copper and copper to regular brass joints are really good looking... Like i believe I should be paying myself top dollar to do this. I am down to my last joint that happens to be a lead-free fitting, and now I'm like, I'm glad I'm not paying myself to do this crappy job.
  • ChrisJ
    ChrisJ Member Posts: 13,576
    I've been using Oatey tinning flux and Bridgit solder and it's been working good for me.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • mattmia2
    mattmia2 Member Posts: 6,713
    The propex fittings are so massive that i heat almost entirely the propex fitting, not the copper.
  • 109A_5
    109A_5 Member Posts: 453

    I am using a propane torch. I've tried it on really low heat, and also medium heat.

    I'm wondering if using propane is not doing yourself any favors. Mapp and Acetylene / air (turbo torch) are hotter and seem to work better in general. With more substantial fittings, by the time you heat the joint up enough your flux is long gone.



    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • hot_rod
    hot_rod Member Posts: 17,569
    too hot! With large LF brass you need to heat the fitting and tube evenly.  The fittings expand and don’t transfer the heat to the tube

    Find some 50/50 solder, 95/5 melts really close to theme burn point if water solvable fluxes, it is the hardest solder to work with

    Once the tube is hotter enough to flow the solder, heat the base of the fitting and take the torch away.

    old flux?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    PC7060kcoppDJD775EdTheHeaterMan
  • newtonkid88
    newtonkid88 Member Posts: 100
    I have seen this video and also the Uponor video.

    I've tried all different techniques. High heat, low heat, heat only the brass fitting, heat the brass then the copper interchanging, literally circling around the fitting for even heat (not just top and bottom), I give up.

    But I'm done with this lead-free stuff for now. I'm going the threaded copper route as mattmia has stated. I have no issues with copper on copper sweating. I actually used to enjoy soldering until this last fitting.
    109A_5 said:

    I am using a propane torch. I've tried it on really low heat, and also medium heat.

    I'm wondering if using propane is not doing yourself any favors. Mapp and Acetylene / air (turbo torch) are hotter and seem to work better in general. With more substantial fittings, by the time you heat the joint up enough your flux is long gone.



  • newtonkid88
    newtonkid88 Member Posts: 100
    edited August 21
    It is my understanding that 50/50 is tin and lead. That kind of defeats the purpose of a LF brass fitting.... not that I need LF for my application.
    I am curious though, so I will try it one more time, this time using 50/50, before I go the threaded copper route.
    hot_rod said:

    too hot! With large LF brass you need to heat the fitting and tube evenly.  The fittings expand and don’t transfer the heat to the tube

    Find some 50/50 solder, 95/5 melts really close to theme burn point if water solvable fluxes, it is the hardest solder to work with

    Once the tube is hotter enough to flow the solder, heat the base of the fitting and take the torch away.

    old flux?

  • george_42
    george_42 Member Posts: 115
    my supply hopuse carries copper pex sweat fittings
  • mattmia2
    mattmia2 Member Posts: 6,713
    50/50 is a lot easier to work with because the melting point is lower. there is a larger range between the temp where the solder melts and the flux burns and becomes ineffective. the temp where lead free solder melts is very close to the temp where the flux burns.
    DJD775
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,671
    After using 95/. Silvabrite or whatever and you go back to 50/50 the 50/50 melts like an ice cube. Nothing wrong with using it on heating.
  • pecmsg
    pecmsg Member Posts: 3,341
    I use a product called Stay Brite #8
    high silver content. Great product. 
  • jumper
    jumper Member Posts: 1,908
    109A_5 said:

    I am using a propane torch. I've tried it on really low heat, and also medium heat.

    I'm wondering if using propane is not doing yourself any favors. Mapp and Acetylene / air (turbo torch) are hotter and seem to work better in general. With more substantial fittings, by the time you heat the joint up enough your flux is long gone.



    Not a journeyman myself but have observed often. The guy who lugs in two tanks seems to succeed every time. Also know guys who swear by no heat joining like epoxy or copperbrite. I'm told that quality of epoxy makes big difference.
  • newtonkid88
    newtonkid88 Member Posts: 100
    SUCCESS WITH THE 50/50 SOLDER! Thanks
    DJD775
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,671
    95/5 is always difficult at least for me.


    newtonkid88kcopp
  • rick in Alaska
    rick in Alaska Member Posts: 1,389
    I'm not sure what it has in it exactly, but sweating Uponor fitting adapters are a real pain for me. The regular ones seem to do ok, but not the fitting adapters. They just seem to burn, tun red, and not flow, even if I heat it real slow. If I have to do them, I usually heat them up with them out of the socket a little, and then push them in when it looks like the solder flows. Basically, I avoid them at all costs.
    Rick
  • newtonkid88
    newtonkid88 Member Posts: 100
    The 50/50 solder with a 95 tinning flux worked really well for me. The 50/50 melted like butter. I made sure to apply the heat evenly, not just 2 opposing spots. Actually moving the flame all the way around steadily.

    I'm not sure what it has in it exactly, but sweating Uponor fitting adapters are a real pain for me. The regular ones seem to do ok, but not the fitting adapters. They just seem to burn, tun red, and not flow, even if I heat it real slow. If I have to do them, I usually heat them up with them out of the socket a little, and then push them in when it looks like the solder flows. Basically, I avoid them at all costs.
    Rick

  • Dave Carpentier
    Dave Carpentier Member Posts: 352
    edited August 27
    Coming from a history of using lots and lots of high lead solder when closing lead pipe splice cases for telecom cables, the first time I tried one of those new solders.. i was like "**** ?" (whiskey tango foxtrot)
    Heating up a quarter pound of solder enough to push it around with an asbestos pad, but not so hot that it dripped off (or melt the lead pipe).. fun times.
    30+ yrs in telecom outside plant.
    Currently in building maintenance.
  • mattmia2
    mattmia2 Member Posts: 6,713
    50/50 has a significant range where it is plastic but not liquid. they would do the same thing to do automotive body work with lead.
  • kcopp
    kcopp Member Posts: 4,036
    One trick i have used w/ Uponor fittings is to take a clean section of sandcloth and clean the face of the fitting. It will get any junk off the fitting. Also allows a place for the solder to stick to w good flux application. i am usually using silverbrite.... 95/5 is the pits.
    GroundUp
  • GroundUp
    GroundUp Member Posts: 1,475
    kcopp said:

    One trick i have used w/ Uponor fittings is to take a clean section of sandcloth and clean the face of the fitting. It will get any junk off the fitting. Also allows a place for the solder to stick to w good flux application. i am usually using silverbrite.... 95/5 is the pits.

    Bingo. I always clean and flux the face of brass fittings, very seldom have issues with any of them using Nokorode flux and Bridgit lead-free solder. Oddly enough, the most troublesome are non-potable fittings.

  • HEATSPEC
    HEATSPEC Member Posts: 9
    Err...... Why use a 1/2" Propex x female sweat? Doesn't someone make a 1/2" pex x 1/2" male or female p.t.? then buy a conventional male/female p.t. x sweat adaptor and use IT? Even if you've got a couple dozen to install, the time saved in ease of soldering will help offset threading on the additional fitting, and the extra expense should be nominal. LeakLock "blue goo" will ensure a permanent seal.
    As for sweating the lead-frees, yes, they can be challenging. I use that Oatey grease-based flux STIRRED WELL before each application and have sworn by, not at, Bridgit for decades. My torch is a Victor air/acetylene Turbotorch but note that size DOES matter, and the [interchageable] tip should match the fitting to be sweated. I always keep the flame moving around, starting with the tubing just above the socket, to start driving heat into the socket, then move to the socket itself, then back off to the junction area. Normally the flame will just begin to turn "Irish" [green] when the Bridgit is applied; note that Bridgit's melting point is significantly higher than, say, 50/50 but its ability to fill is terrific. Now NOTE that the major problem with lead-free fittings is that their conductivity is significantly LOWER than conventional brass, so keeping it evenly heated is a MUST. Also note that one function of cleaning both tubing and socket is to create those scratches that act as capillaries to help draw the solder into the socket. Hope this helps.

    Hey, if worse comes to worse you can always cheat, put on the next bigger torch size and get out the Harris 15 braze. THAT's never failed me [shhhhh....!].
  • ChrisJ
    ChrisJ Member Posts: 13,576
    HEATSPEC said:

    Err...... Why use a 1/2" Propex x female sweat? Doesn't someone make a 1/2" pex x 1/2" male or female p.t.? then buy a conventional male/female p.t. x sweat adaptor and use IT? Even if you've got a couple dozen to install, the time saved in ease of soldering will help offset threading on the additional fitting, and the extra expense should be nominal. LeakLock "blue goo" will ensure a permanent seal.
    As for sweating the lead-frees, yes, they can be challenging. I use that Oatey grease-based flux STIRRED WELL before each application and have sworn by, not at, Bridgit for decades. My torch is a Victor air/acetylene Turbotorch but note that size DOES matter, and the [interchageable] tip should match the fitting to be sweated. I always keep the flame moving around, starting with the tubing just above the socket, to start driving heat into the socket, then move to the socket itself, then back off to the junction area. Normally the flame will just begin to turn "Irish" [green] when the Bridgit is applied; note that Bridgit's melting point is significantly higher than, say, 50/50 but its ability to fill is terrific. Now NOTE that the major problem with lead-free fittings is that their conductivity is significantly LOWER than conventional brass, so keeping it evenly heated is a MUST. Also note that one function of cleaning both tubing and socket is to create those scratches that act as capillaries to help draw the solder into the socket. Hope this helps.

    Hey, if worse comes to worse you can always cheat, put on the next bigger torch size and get out the Harris 15 braze. THAT's never failed me [shhhhh....!].

    What size tips do you use for general plumbing like 1/2" and 3/4"? A3?

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • mvickers
    mvickers Member Posts: 20
    Yep, 15 will def do it, but I'd 1st go with SB #8