Soldering copper fitting with teflon tape on the thread end of it

CountryBumkin

CountryBumkin

Active Member
Messages
915
Reaction score
70
Points
28
Location
Orlando, FL
I'm installing a Steam Generator. I have to solder a copper 90 deg fitting onto a short threaded copper fitting which is threaded into the Protection Valve. Thiscopper fitting has threads on one end a slip coupler on the other end.
Since I can't thread the fitting into the Steam Generator once the 90 is installed, I have to install the threaded fitting first then solder the fitting.

So my question is, will the teflon tape on the copper threads burn/melt off during the soldering? I'll try to wrap threaded part with wet rag - but the whole fitting is only two inches long.

SG-fittings.jpg
 
Last edited by a moderator:
Do it in a well ventilated area especially if you have birds. There have been many cases of dead birds due to Teflon cookware.
 
That valve should never pop during normal operation, so I wouldn't worry much about the tiny bit that may leak past the threads if it were to.
 
It will certainly burn if you're heating the same fitting and soldering the other end of it.

I would solder a short chunk of pipe to the threaded fitting first, then tape/thread it in, then solder the 90 to the short pipe... You'll have more room between the torch and the tape, more copper to soak up the heat, and more room for wet rags etc. etc.
 
I assume every threaded copper fitting will have a straight section of pipe sweated onto it. Just sweat the straight part without the elbow and then thread it in place, sweating the elbow afterwards.
 
Last edited:
Good point. If the valve pops/opens, anything that drips will go into the drain pan.


I can't add much of a straight section because the pipe needs to clear the top edge of the drain pan. Not much room to exend the 90 downward.

Is there any concern that I could damage the pop-off valve from the heat?
 
A lot of that PTFE tape is rated for 500 deg F.

Check what the rating is for the tape that you are using, Then do not exceed that temp.

Some of the cheap plastic tape is not even Teflon. Don't let the looks fool you. Check the specs.
 
LLigetfa said:
I assume every threaded copper fitting will have a straight section of pipe sweated onto it. Just sweat the straight part without the elbow and then thread it in place, sweating the elbow afterwards.
Click to expand...

You're right. I need to sweat a short (maybe 3 inches) straight piece into the threaded fitting then sweat the 90 onto that. But even then, my 90 is only about 1/2 inch away from threaded coupler. I guess I'll give it a try and see what happens.

PS. No birds in house - just birdbrain wife.
 
If you are referring to the connection to the pressure relief valve, (since it is a steam generator it has NO temperature sensing function), there is NO pressure in the line so it makes little difference whether the Teflon melts or not.
 
The bottom valve looks like a drain doesnt need anything, maybe a street el hand tight.

The union is a no brainer - take it apart

The relief valve can have a brass nipple and el attached to it. Supposed to go outside anyway.
 
Could he us a minimum length strait into the threaded fitting, then use a push connect (shark-bite) 90 ?

or maybe a low heat solder?
 
dlarrivee said:
Exactly.

I don't see why any of that stuff needs to be soldered in place...?
Click to expand...

I think you're right. Brillant! Why don't I just install a NTP to PEX coupler and use that to get the drain, flush valve, and relief valve, to the outside? I have plenty of 1/2 inch PEX tubing and fittings. That would sure make the drain runs alot easier.

On the pressure relief valve, if it ever opens the discharge will be hot. Should I run some length of copper first then switch to PEX? I don't want to melt the PEX.
 
If that relief valve EVER discharges it will be at 250 degrees and WILL melt the PEX no matter how much copper you have between it and the valve. Use ALL copper.
 
CountryBumkin said:
I'm installing a Steam Generator. I have to solder a copper 90 deg fitting onto a short threaded copper fitting which is threaded into the Protection Valve. Thiscopper fitting has threads on one end a slip coupler on the other end.
Since I can't thread the fitting into the Steam Generator once the 90 is installed, I have to install the threaded fitting first then solder the fitting.

So my question is, will the teflon tape on the copper threads burn/melt off during the soldering? I'll try to wrap threaded part with wet rag - but the whole fitting is only two inches long.View attachment 14637
Click to expand...


You can safely solder a fitting that has been thread taped. I actually use thread tape in conjunction with liquid thread sealant, for I use both when doing Water lines. I do it both on pop-off lines as well as threaded ball valves (If I have to) on Therma Star TS11-120-1s, Standard HW Heaters, Commercial Rotisserie Ovens, Steamers, Water lines from 1/4 to 2.5" ect ect. I have never had a leak as a result of sweating a fitting with thread tape. As long as you take care not to heat the tape directly under flame, there will be no problems.
 
dlarrivee said:
It will certainly burn if you're heating the same fitting and soldering the other end of it.

I would solder a short chunk of pipe to the threaded fitting first, then tape/thread it in, then solder the 90 to the short pipe... You'll have more room between the torch and the tape, more copper to soak up the heat, and more room for wet rags etc. etc.
Click to expand...

It works but taking the time to pre-sweat is not always possible, or even worth the hassle. I had a water line repair, 25ft over a sales floor that afforded me no room or time to pre-sweat anything. Thanks to that experience and 6 years later, I NEVER waste time pre-sweating male adapters because you just don't have too. As somebody else said, as long as you use real Teflon, you won't have any trouble.
 
Usually when I'm using a male adapter it is for a plastic laundry box, or an outside hose bib and I'd rather work away from the plastics or tight wood spots, than close to them.

If he is worried about getting things too hot, then he can pre-sweat, if he is skilled enough to work right against the generator itself, then all the power...
 
CountryBumkin said:
I'm installing a Steam Generator. I have to solder a copper 90 deg fitting onto a short threaded copper fitting which is threaded into the Protection Valve. Thiscopper fitting has threads on one end a slip coupler on the other end.
Since I can't thread the fitting into the Steam Generator once the 90 is installed, I have to install the threaded fitting first then solder the fitting.

So my question is, will the teflon tape on the copper threads burn/melt off during the soldering? I'll try to wrap threaded part with wet rag - but the whole fitting is only two inches long.View attachment 14637
Click to expand...

I had a similar problem. You know, after you solder it, you're going to suspect that the tape will have melted and/or at least loosened up. But there's no way to check it then. To give myself peace of mind, in a similar situation, I soldered 3 inches of pipe to the fitting then applied tape and twisted it in, nice and tight. Then I used a straight fitting with more pipe. Three inches away, the heat probably won't affect it.
 
You must log in or register to reply here.

Similar threads

I
Sprinkler Backflow assembly - Replacing PVC with Copper
Replies
2
Views
2K
insearchofanswers
I
adiner
Removing and replacing an in-line ball valve
Replies
0
Views
5K
adiner
adiner
mcat
Taco pressure reducing valve leaking - questions about copper to cast iron connection
Replies
15
Views
2K
mcat
mcat
T
keeping PVC compression fittings and unions from unscrewing?
Replies
7
Views
4K
John Gayewski
John Gayewski
NIS240SHU
New Well Pump and Pressure Tank - Worked for 24 hours
Replies
7
Views
1K
NIS240SHU
NIS240SHU
Back
Top