Threading Black Pipe

[Bill Turpin]

Sil-phos is a self fluxing material. If you want a good leak free joint you should still sand the fitting and copper clean. Sil-phos is very strong, however the additional heat needed weakens the copper so that over all it is less strong. The actual joint is sooo strong, and the added heat necessary makes it almost impossible to modify or take apart a joint. A 95/5 solder joint can be modified many times as long as it is cleaned every time.

One of the tricks to soldering is to clean and flux the solder before heating. Apply the heat to where you want the solder to be sucked to. Do not apply heat directly to the solder.These two steps will prevent the solder from oxidizing. Oxidation causes pin hole leaks. I recomend LACO brand paste flux. It changes color (darkens) just before the copper is hot enough for proper solder flow. Heat the fitting with the fluxed solder in the area, but not in the flame. This will pre-heat the solder but not melt it. When hot enough, touch the solder to gap to be filled. It should be sucked in. Apply solder until one drop of solder falls off.

For heat sensitive valves, filters, etc solder threaded adapters to six inch lengths. Screw into device and then connect to the system with a coupling. Buy a fitting brush and use sanding strip to clean tube end, inside the fitting, and the outside lip of the fitting. Apply flux to the tube, insert into fitting, and twist to disperse the flux. Then wipe the oozed out flux around and on the fitting lip.

The nice thing about copper is that modifications can be easily made anywhere in the system.

Slope downhill whatever piping used to a water trap. At end of runs put a tee (instead of an ell) with a cap for later additions.

Bill in WNC mountains

["Gary Brewer"]

Chris: You mentioned your joints coming apart. If you are going to solder say an ell ( 90 degree ) always solder the lower joint first and then the upper joint. If you don't and solder the top first and then the lower when you do the lower you can suck solder from the top joint and weaken it. Of course both joints to be soldered should be prepared at the same time with emory cloth cleaning, and a good paste flux. If you want a clean look you can also wipe the bottom of the joint with a cloth or paper towel just be sure to wipe away from you so that you don't flick solder on yourself. Also you can use the old lead solder on an air line since you are not going to drink water from it ( I hope? ). The old 50/50 solder is easier to solder and does not require the higher temps that the new lead-free solders do. That is why you've seen the mapp gas torches being so popular because to solder 3/4 copper pipe with the new solder is a lot harder with the old propane gas and it is just easier to use mapp gas.
Gary

[Nancy Laird]

Compressed air and PVC is a big mistake , PVC breaks into shards when it fail which can be dangerous.
Mike

We've had our air lines in our shop for 13-1/2 years using PVC with nary a failure of either pipe itself or a joint. We have a 5hp compressor with a 125psi max pressure (we regulate down to about 100psi), the air is used fairly often for spraying or other uses (2 or 3 times per week)-LOML even uses it to air up the tires on the trailer and RV on occasion. Our experience might be difference than others', but the PVC has worked for us.

Nancy

[Al Willits]

"""""""""""""
Sil-phos is a self fluxing material. If you want a good leak free joint you should still sand the fitting and copper clean. Sil-phos is very strong, however the additional heat needed weakens the copper so that over all it is less strong. The actual joint is sooo strong, and the added heat necessary makes it almost impossible to modify or take apart a joint. A 95/5 solder joint can be modified many times as long as it is cleaned every time.
""""""""

Must not work with it much, we use it on A/C lines that run close to 400 psi pressures and don't ever clean it, resolder it on a regular basis and unsolder the joints many times with out any problems.
When I say not cleaned I'm talking about the oxidation on the copper, not chunks of dirt/whatever btw
Weaker? If so, not hardly enough to matter in A/C lines so I doubt a 120 psi air line is gonna bother it.

Al

[Russ Cass]

Chris, I'm planning on piping my 2 car garage for air this spring and
decided to sweat copper rather than wrestle with black iron pipe.

The cost will be slightly higher, but the aggravation factor is way lower

Russ

[Charles McKinley]

Hi Chris,

Welding is a great skill but price some WeldBend fitting and I don't think you will want to use it in the shop.

[David G Baker]

Al,
Thanks of the teaching offer. I probably won't be headed your way anytime soon the LOML has Virginia and Georgia on her mind so you know where I will be going on vacation.
I have a Hobart wire rig and a couple of stick welders. I can weld but it has been a while and need to get back at it and do a little practicing. My gas bottle is empty on the Hobart rig so I have been using flux core. Not a pretty but it works.
To keep this on a wood oriented topic, I have to build me a few stands for a some of my wood working tools. I have a Delta 12 inch lunch box, Delta 6 inch jointer and a Delta shaper.
I also am going to run a bunch of air lines in my pole barn and will be using copper. My next big purchase is going to be a two stage compressor. Not that I need it but have wanted one for years. I use a airless portable that will do most of what I need but it is slowly dying and when it gets buried I am going to get the big stationary unit.
David B