Don't Blow Your Foot Off!

[taylormade]

After starting another of the seemingly endless threads on compressor piping (The Price of Copper) and getting lots of good advice from forum members, I decided to go with one inch copper.

I started the project today with some trepidation as I’ve never soldered much in my life and most of that was electrical under the hood of a car. I dove in and had everything done up to my first shut-off valve by about eleven this morning. I decided to test the quality of my soldering by pressurizing the system. I turned the valve. BLAM! Like a shotgun going off. One of my joints had failed with spectacular results, blowing off the bottom drain valve and just missing my foot. I called over my next door neighbor, an old contractor, and he said the rest of my work looked good and I may just not have gotten enough heat on that particular joint. We redid it, hooked everything back up, stood back and gently turned on the valve. Everything held rock steady and has been holding fine for the rest of the day under 175 pounds pressure.

Looks like I’ll finish tomorrow, if I don’t blow my foot off in the process.
RT

 

[Junkman]

Not enough heat, and you will have cold soldered joints. I have seen cold solder joints be fine for many years, and then start leaking. Don't be afraid to use lots of soldering paste, heat, and solder. Just wipe the joint after soldering it. If the joint doesn't wipe, then it is a cold joint. You will rapidly learn which ones need to be redone, and those that are good.. What is the going rate today for 1" copper ????? Did you use L or M?????

 

[GSSFC]

Just curious. If you solder a joint and it leaks. What is the preferred method to resolder? Can you just wipe more flux on the joint and reheat, then apply more solder? I used 1" copper for mine, the higher grade. I didn't have any leaks, but I always wondered how you solve that problem if it arises.

Thanks, Tim

 

[Junkman]

Sometimes you can save a joint by doing what you are suggesting, but most times, it needs to come apart to be done properly. I have successfully re soldered joints and not had any leaks afterward. With air piping, it is a lot easier to save a joint by re-soldering than it is with a wet system. Most times, the water turns to steam and spoils the joint.

 

[rhandwor]

Get the joint hot enough that when you hold say 95/ 5 solder to the joint it is pulled in when heat is removed. Buy a map gas torch its much easier they are fairly cheap.

 

[usa#1]

There is a lot of stored energy in compressed gases, especially at 175psi. When I get around to running my air lines, I'm planning on iron pipe with threaded connections, I just feel it's safer, but that's just me.

You could lower the pressure considerably in the distribution piping by installing a regulator after the compressor before the distribution piping. Maybe set it to 120 -130 psi. I don't think running the distribution lines at 175psi gains you much. I didn't see a need for my tank pressure to be set to 175psi, so I adjusted my pressure switch setpoint to 135psi. I know I lost a little stored volume in the tank, but I haven't noticed any difference even using the blast cabinet.

 

[matt_i]

I hate to be a wet blanket but I think if you used "box store" solder (IOW "lead free") you made a grave mistake running 175psig line pressure.

This cheapo solder creeps under such static loads....

My choice would either be a silver solder, brazing rod, or best, JW Harris Sta-Brite #8 solder which applies like a soft-solder but has much better mechanical properties and will not creep. We used it in installation of a 1" copper line running 250-300 psig constantly cycling in a refrigerant transfer system....worked excellent for the 10 years I was involved with it. This solder costs a lot (available thru refrigeration suppliers) but "wicks" like the old leaded solders (although it does not contain lead and is safe for potable water systems) and does not require significant extra heat like traditional silver brazing...although with a 1" pipe I'd strongly consider MAPP or oxy-air at minimum, oxy-acet even better.

http://www.harrisproductsgroup.com/pdf/spec/Solder/HARRIS_STAY_BRITE_8_SILVER_BEARING_SOLDER.pdf

I would dial your line pressure back to ~100psig for safety reasons if it were me.

Edit: I think the excellent wicking action I mentioned is aided by the Stay-Clean flux by the same company. I've always used both in tandem.

 

[Torque1st]

You most likely did not get the pipe/fitting hot enough and just heated the solder up. Always remove the torch and apply the solder to the joint. The heat from the joint should melt the solder and it should wick into the joint and flow around it.

You can apply too much heat and oxidize the fittings.

The best way to heat a joint and test the temp is to heat the joint then remove the torch and touch the joint with the solder. If the solder melts instantly and flows you have the temp correct.

Do not use regular plumbing solder for air lines. Use 50/50 silver solder or the solder discussed above^^.

 

[e-tek]

Another reason to go with Black Pipe....people that think sweating pipes can be self - taught!! Be Careful!!

 

[taylormade]

I used the silver solder and MAP gas. The joint that let go was one of my early attempts. My contractor friend helped me this afternoon and I got the method down pretty well - I didn't use enough heat or solder on that joint. since I'm using one inch pipe I needed to work around the fitting a bit more for even heat. I've run the first drop line this evening and everything held just fine. Unless my garage explodes tonight, I think this will work fine.

The one inch ten foot lengths were 18 bucks at HD. It's type L. Cheapest I've seen in quite awhile.
RT

 

[babzog]

Get the joint hot enough that when you hold say 95/ 5 solder to the joint it is pulled in when heat is removed. Buy a map gas torch its much easier they are fairly cheap.

+1 on the map gas. I'm sure propane has its uses but map gas is much easier and faster.

 

[nadogail]

When soldering air lines with a Propane Torch I found 50-50 solder (50% tin and 50% lead) to work very well. Because the air pipes do not carry water, I avoid the hassels of trying to make leadfree solder work with the limited heat of Propane.

 

[nate379]

I don't see why it can't be.

I learned how to weld when I was 10 by my Dad giving me some rods and scrap steel.

Another reason to go with Black Pipe....people that think sweating pipes can be self - taught!! Be Careful!!

 

[Junkman]

When soldering air lines with a Propane Torch I found 50-50 solder (50% tin and 50% lead) to work very well. Because the air pipes do not carry water, I avoid the hassels of trying to make leadfree solder work with the limited heat of Propane.

Just don't breath the compressed air..

 

[Red'n'WhiteRebel]

Just as important as heat and solder application is proper surface preparation. Use the proper size wire brush style cleaner and scuff the fitting and the pipe well. This helps the solder travel and makes for a solid joint. If you get a bad joint, sweat it apart and re-prep it. Peace of mind. My 2 Cts.

 

[ddawg16]

Rednwhite is right.....PREP!.....you can't get it clean enough.....

I actually use two things besides the wire brush.....sand paper and 3M scratch pad.....I use the sand paper to get the majority of the trash off....then a clean 3M pad to get it really clean....

Test for proper fit....not too tight...not too loose....too tight and the solder can get between the copper...too loose and you are depending on the solder for strength...

Plenty of flux.....it's kinda like a primer.....

Then heat...as noted above...MAP is best......don't be in a hurry to get the solder one....and heat up the heavier piece first....you know you have the right temp when you can touch the solder to the joint and it '*****' up the solder.....if the solder just kind of lays there and bubbles....the copper is either not hot enough or not clean enough....a good clean hot joint will literaly **** up the solder as fast as you apply it....the moment it starts to collect at the bottome....you are done.

You do not want the solder to have a built up look on the outside....it should have a nice clean 'flush' and even look to it all around the joint.

One thing I learned from a plumber friend when doing copper for water....make sure to debur the inside of the pipe....he said that over time a rough inside edge allows the water to start to errode the material and could leak over time.....plus the smoother edge gives the solder a nice surface to cling to and makes for a really smooth joint inside the pipe.......I was able to see what he was talking about by playing with a couple of couplings....

 

[Junkman]

I use a plumbers acetylene torch with the B tank for doing all my soldering jobs. When I built my home, I used 50/50 solder, and still haven't had any effects of lead poisoning. Personally, I think this whole lead poisoning theory is way over blown. I grew up in a home with lead paint, rode in cars that burned leaded gasoline, and had water pipes soldered with lead based solder, as well as most of the others my age on these forums. The only difference was that our parents didn't allow us to chew on the window sills, or eat paint chips. Back then, parents were responsible for the child's welfare, and took that responsibility seriously. Today, many parents don't do much parenting, and depend on government to keep the children safe by passing more laws.

 

[e-tek]

Junk - YOU can't see the effects of lead pisoning - but WE can!!!!

Ddawg - AWESOME sweating clinic right there - thanks. I've only done it twice, the first time didn't hold cause I didn't learn before trying it and the second time it's still holding (water) cause I watched the plumber closely.

BUT - and this goes back to my first post - there's way more to this than heat and solder. If you're going to be standing beside an air system you built with little expereince and it's holding enough pressure to "blow off your foot", then you'd had better learn how to do it properly!!

Same for welding metal - lots of things you weld aren't critical, but if your life depends on it, you should know more about welding than plugging in and triggering a MIG welder. JMO.

 

[TexasT]

Most times, the water turns to steam and spoils the joint.

In my opinion propane is a waste of time. Get a cylinder of map gas(the yellow one). Also the torch you use must be for map gas. I would search out a plumbing supply house and get a good torch. More money but how many are ya gonna buy?

As for the water pipe and the steam. Get some bread and stuff the pipe full to keep the water off the joint while you are working with it. The bread will disintegrate in the water and the joint will hold. Old trick I learned from an old plumber.

 

[Junkman]

I also know the bread trick, but you have to pick the correct bread. Only use white bread, because the 12 grain bread will cause you problems.. Did the old plumber tell you that you should run the bathtub faucet to get the disintegrated bread out of the lines? If you run any of the other faucets or the toilet, the strainers will become clogged. Toilet valves are somewhat more forgiving than the strainers, but even those get clogged sometimes with debris.

 

[Charles (in GA)]

According to the specs in the Copper Tube Handbook, by the Copper Development Association, 50-50 solder is not strong enough to use on joints for compressed air systems.

Look at the tables on Page 28, and you will see that you need 95-5 solder to make a joint capable of safely handling the pressure.

Charles

 

[TexasT]

I also know the bread trick, but you have to pick the correct bread. Only use white bread, because the 12 grain bread will cause you problems.. Did the old plumber tell you that you should run the bathtub faucet to get the disintegrated bread out of the lines?

No, but it sounds like good advise.

 

[Torque1st]

I also know the bread trick, but you have to pick the correct bread. Only use white bread, because the 12 grain bread will cause you problems.. Did the old plumber tell you that you should run the bathtub faucet to get the disintegrated bread out of the lines? If you run any of the other faucets or the toilet, the strainers will become clogged. Toilet valves are somewhat more forgiving than the strainers, but even those get clogged sometimes with debris.

+1 on that! Only use the center of the bread, not the crust.

Also the water puts a film of deposits on the bad joint that will effectively keep it from being repaired unless you "glob" the solder around the outside. -Bad practice, but there are a couple of old joints in my house like that from the PO. With water pipes a person usually has to take the joint apart and heat the parts to get the solder to run off then clean the parts with sandpaper and brush. Apply flux which is actually a chemical cleaner and re-assemble the joint. Sometimes heat is required to soften the solder remaining in the joint.

Personally I think the lead solder scare is about brand new pipes. Once the water pipes have been in service a short time a lime scale builds up that covers the solder. I have read studies to that effect somewhere.

Remember, use high temp hard solder for air lines, not regular plumbing solder. A Mapp torch or Acetylene is required. BTW- Actual MAPP gas is no longer available in the US for some strange regulatory reason. So we now use Map-Pro gas...

 

[december45]

I've been told only to use silver solder to solder joints for compressed air, that sweating the joints with 50/50 or 95/5 will not do the job, not using silver solder is as dangerous as using pvc... just what ive been told.

 

[taylormade]

I finished the piping this afternoon. System held 175 pounds for the rest of the day. I ran several air tools with great results. No water in the lines or in my filtration system and no leaks in the 80+ feet of pipe I ran. I like the looks of the copper and think I made the right choice - at least for me. I used type L copper and silver solder with a Map torch and will do it again when I expand my system later this summer. Good prep, clean joints, plenty of heat applied to the right places made the work go fast. I no longer feel like a novice when it comes to soldering - and only one minor burn on my pinky!
RT

 

[Junkman]

Don't forget that you have to polish the copper every week...........

 

[Charles (in GA)]

I've been told only to use silver solder to solder joints for compressed air, that sweating the joints with 50/50 or 95/5 will not do the job, not using silver solder is as dangerous as using pvc... just what ive been told.

Spend a moment looking at the specs in the Copper Tube Handbook, by the Copper Development Association, (P.28) and you will see that while 50-50 solder is not strong enough to have a margin of safety, that 95-5 solder has more than enough margin of safety and silver solder is overkill.

Charles

 

[Torque1st]

Personally I think silver solder should be used to get the heat resistance for fire. Just that extra minute can make a difference.

I don't know for sure, but I have the feeling that soldering materials is why copper is banned for air lines in a few municipalities. I wish I could find more information on it. I don't recall the search terms I was using when I found those codes. I have not found them since but they are out there. If anyone finds them please let us know. At the same time I am still vacillating between galvanized and copper. I may not know which I will use until I buy the materials. Copper is certainly far easier. Maybe the architect or city codes people will make up my mind for me. They will probably spec iron pipe tho...

 

[Identaltech]

In most Dental office they use 95-5 for air lines.
The silversolder is used for Med Gas.
never had a joint fail.
the company I work for has been doing this for 75 years.

 

[rickairmedic]

Taylor I would bet the joint that failed was also a BRASS 1/4 turn ball valve . You have to sink alot of heat into them to get a good joint due to their mass they take alot more heat than just a copper to copper joint.


Rick

 

[taylormade]

Rick, you'd lose the bet. It was a reduction fitting that went south. I narrowed the pipe to the drain down to 3/4 to save some money on the ball valves. Thinking it over, I was guilty of being really stupid. Examining the joint after the failure I couldn't find any real solder on the joint. Like an idiot, I put several sections of pipe and fittings together, then soldered them. Duh! I think I forgot to solder that joint! The way the part shot off the moment pressure hit the lines leads me to believe I pulled the ultimate brain fade and never put solder to the fitting. Needless to say, I examined every one of my joints after that - and examined them very carefully. The moral - don't rush the job, take your time and pay attention to what you're doing..

And, yes, I quickly noticed the valves took a lot longer to heat up to the correct temperature. As soon as I took some of the advice posted above about taking the heat away from the part, then letting the solder flow, certainly improved both the quality and appearance of my work. Thanks everyone for the help.
RT

 

[redsky49]

In most Dental office they use 95-5 for air lines.
The silversolder is used for Med Gas.
never had a joint fail.
the company I work for has been doing this for 75 years.

In hospitals, the standard piping construction for med gases (air. vac, oxy, etc.) that I have experienced is cleaned and capped copper (Med Gas quality, ASTM B-88) with 95/5 or silver solder. There are several more requirements that also cover fittings, tools, sterilizing, etc. That being said, the preferred method is to braze all connections using a brazing material that has a melting point above 1000 degrees F. This is not propane territory. For those who do not know, the significant difference between soldered and brazed joints is that the brazed joint metal melts at a much higher temperature, typically 1200 - 1500 degrees F, rather than 500 degrees as in soldering, and the braze metal is much stronger than solder. A properly brazed joint is stronger than either the pipe or the tube being joined. Many of us (myself included) throw these terms around casually when discussing joining copper tubing. When used for the pressures discussed here, the correct term is brazing.

This piping is installed by (on my jobs) qualified pipe fitters, pressure tested, purged, checked, tested and checked again by an outside authority (who also confirm that no piping has been cross connected), viewed by myself, and finally checked by the hospital before the installation is signed off.

I would have no concerns at all about using this for a home garage installation. I would be extremely careful about testing any system at such high pressures though. A 50/50 soldered joint can be accomplished at a lower temperature and thus a lower final strength, and should not be trusted to maintain safely the pressures you are using (175 psi).

As always, offered only as opinion

 

[rickairmedic]

Rick, you'd lose the bet. It was a reduction fitting that went south. I narrowed the pipe to the drain down to 3/4 to save some money on the ball valves. Thinking it over, I was guilty of being really stupid. Examining the joint after the failure I couldn't find any real solder on the joint. Like an idiot, I put several sections of pipe and fittings together, then soldered them. Duh! I think I forgot to solder that joint! The way the part shot off the moment pressure hit the lines leads me to believe I pulled the ultimate brain fade and never put solder to the fitting. Needless to say, I examined every one of my joints after that - and examined them very carefully. The moral - don't rush the job, take your time and pay attention to what you're doing..

And, yes, I quickly noticed the valves took a lot longer to heat up to the correct temperature. As soon as I took some of the advice posted above about taking the heat away from the part, then letting the solder flow, certainly improved both the quality and appearance of my work. Thanks everyone for the help.
RT

LOL Ok you win I wasnt thinking you forgot to solder a joint . That will make it fail real good as well . I have done the same though myself once or twice so dont feel bad I agree rushing will get ya every time fortunately I usually catch the OOOOOOOOOPS while doing the vacuum on the lines before loosing all the freon .


Rick

 

[e-tek]

Anyone else getting hungry??
How bought a nice copper sandwich?

 

[taylormade]

Ted days, no leaks, no problems and virtually no water in the lines even with the 90 percent humidity we've been experiencing. I'm real happy with the copper and would do it again given the chance. It took me about 12 hours to run 60 feet of pipe, two drops and one drain line at the end of the system, add the regulators and filters and solder everything together. My air drops rise 10 inches up from the main line, then down to a valve, then a filter and regulator, then another valve. No water in those lines at all. The end drain line spritzed out a few drops after I gave the compressor a workout the other day using my air ratchet to change the clutch on my 48 Plymouth.

This was my first shot at non-electrical soldering, and if a klutz like me can do it - anyone can.
RT

 

[gsport]

how about some pictures of all this piping....

 

[InPrimer]

When I got 3/4 in copper for my garage my neighbor insisited that I use silver solder, in fact he did all the sweating, now this guy was into refrig for over 30 yrs and obviously knew how to do it. After reading the above ans. I'm glad I listened to him, remind me to get him an extra 6 pack for his insistance

 

[rinny_tin_tin]

I used the silver solder and MAP gas. The joint that let go was one of my early attempts. My contractor friend helped me this afternoon and I got the method down pretty well - I didn't use enough heat or solder on that joint. since I'm using one inch pipe I needed to work around the fitting a bit more for even heat. I've run the first drop line this evening and everything held just fine. Unless my garage explodes tonight, I think this will work fine.

The one inch ten foot lengths were 18 bucks at HD. It's type L. Cheapest I've seen in quite awhile.
RT

The most frequent cause of failure in sweating copper pipes is deficient cleaning of the joint surfaces. Rule NO. 1 - it is impossible to get a joint too clean.