I can’t solder lead-free brass fittings

newtonkid88

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.

Alan (California Radiant) Forbes

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?

newtonkid88

Alan (California Radiant) Forbes said:

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

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.

EBEBRATT-Ed

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.

newtonkid88

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

EBEBRATT-Ed said:

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

I've been using Oatey tinning flux and Bridgit solder and it's been working good for me.

mattmia2

The propex fittings are so massive that i heat almost entirely the propex fitting, not the copper.

109A_5

newtonkid88 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.

https://youtu.be/xTTH6tAA1Lo

hot_rod

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?

newtonkid88

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:

newtonkid88 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.

https://youtu.be/xTTH6tAA1Lo

newtonkid88

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

my supply hopuse carries copper pex sweat fittings

mattmia2

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.

EBEBRATT-Ed

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

I use a product called Stay Brite #8
high silver content. Great product. 

jumper

109A_5 said:

newtonkid88 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.

https://youtu.be/xTTH6tAA1Lo

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

SUCCESS WITH THE 50/50 SOLDER! Thanks

EBEBRATT-Ed

95/5 is always difficult at least for me.

rick in Alaska

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

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.

rick in Alaska said:

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

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.

mattmia2

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

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

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

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

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?

mvickers

Yep, 15 will def do it, but I'd 1st go with SB #8