VILeninDM

Hey guys,

Don't know if this is the right board, but there is no right board, so I am posting it here.

I installed my new 7HP 60 gal compressor today and starting running 3/4" ID copper pipes for the air. I am curious if anyone has any tricks how to put them up as painlessly as possible.

I soldered together few pipes with T and elbow fittings on the ground and that part is pretty easy (although generally I end up with solder dripping a little inside or outside the pipe), but at some point you have to put things on the wall before connecting them. This is where the question is, what's the easiest way to do this part without setting the wall on fire? Plus with the pipe being close to the wall, it is a bit harder to get to the other side. How do I make sure I get everything sealed?

ede

you ought to be able to pull the lines away from the wall to keep from starting a fire. keep a squirt bottle of water near by to cool off the wall if it does get hot, aluminum foil makes a good heat shield. you don't really need to apply heat directly to the off hand side, if it's hot enough the solder will flow to the heat. might want to install a dirt leg too.

spartyon

when i do a little plumbing at the school in the summer we use a propane torch and plumbing soder on copper tubing. when you do it this way to need to make sure that you put a fire blanket or something like aluminum foil to keep the wall from catching fire. it does a good job and the solder runs around the tubing.

83 Crossfire TA

iTrader: (2)

I’ve run quit a bit of copper pipe and it seems like you can always do it in a way that doesn’t mean pointing the torch at something flammable. Usually joints end up in open spaces so that isn’t that big and issue, and if no it’s easy enough to wait till you have the whole length done to mount all the straps/hangers.

Otherwise, go to the hardware store/home center and get yourself a soldering heat shield… it’s basically like a stiff welding blanket that is about 1’x1’. I have one for just this reason but I don’t think that I’ve ever used it.

Motor City Mike

Check this out:

Air compressor piping diagrams and tips

I'm going to run copper air lines in my new shop.

deadbird

I used rigid nylon air lines in my 'shop' . A little more expensive to buy but, nice stuff and easily modified to expand or re-route.

http://www.griotsgarage.com/catalog.jsp?&SKU=45571B

Motor City Mike

Use a small mirror to see if solder has completely flowed around the joint. You really won't be able to find any small leaks until you pressurize the system though.

They also have an attachment that goes on the end of the torch tip that shields the flame away from the wall (or other flammable materials), and it also helps heat the backside of the pipe/joint.

83 Crossfire TA

iTrader: (2)

If you get the joint clean and sweat it correctly (heat the pipe till the solder melts on it’s own when you touch it to it), the solder will sweat (pull into) the joint and you won’t have any leaks, it just doesn’t happen if it’s done right. Practice on a couple of pieces on a bench and you’ll see what I’m talking about.

91TPI5.7

when you soft solder, especially a line as small as 3/4, learning how to control your heat can keep from having a house fire.

1 dont use too big a tip. like i said its small pipe.
2 dont use a ton of flux, making sure the pipe is clean is more important than the amount of flus you use, and reduces the snot drips.
3 clean the pipe, and the cup of the fitting, a wire fitting brush for the fitting and a scotchbrite on the pipe. Dont polish it, just make sure it has new copper showing.
4 after the joint is assembled heat the pipe portion first, once the flux has finished boiling, heat the cup of the fitting.
5 finally gently touch the solder to the pipe to see if its hot enough. if it is the solder will melt immediately, if not pull away the solder till it is heated.

here is where tecnique is involved. It doesnt take a lot of solder to seal the joint. 1 inch worth of solder is enough to do each joint.

6 once you see the solder take, pull the torch back a little, this is controlling your heat. but keep the flame ON THE FITTING. the solder, once melted, follows the heat.
7. instead of adding solder 360* around the fitting, use the torch to draw the solder already in there around, adding just a dab as needed. Sometimes, if its heated enough, you can take the torch away and feed it solder without a torch, but you should get some experience first.
Usually if you can heat 1/4 to 1/2 the circumfrence of the fitting that should be enough to work the whole thing. If the solder does not tak, then the pipe is not clean, or you missed with the flux. Flux only works on copper, not oxidized copper. if you flux it solder it. Flux is an acid, and it absorbs water. If you live in a humid area, flux some copper leave it over nite, it will be green the next day.
Hope this helps. Sounds like a lot but once you get a pattern, and tecnique, it goes really quick.
Tune in next week, and we will learn how to braze copper with 15% silvaloy.

Irockz

iTrader: (1)

Why not just use plastic pipe?I plumbed my shop in plastic 3/4" CPVC,primed and glued,with no problems or fire hazards.I also had no worries about whether the joints would leak.

VILeninDM

I think compressor manual says to only use metal because the oil used in the compressor may not play nice with the pipe if any of it for some reason gets into a line.

And then if there is a burst for any reason, maybe you even hit the pipe by accident, copper pipe will bend and flex while PVC might just shatter and then you'll have sharpnels flying everywhere.

Just few reasons I've read here and there for not using PVC.

I did finish all my piping and copper worked out pretty well. For most part I just soldered on the floor. Few cases that required soldering on the wall, I just used a piece of scrap metal with a screw to hang it on the wall behind the pipe.

http://dxm004.homeip.net/gallery/vie...05&id=IMG_1032
http://dxm004.homeip.net/gallery/vie...05&id=IMG_1034
http://dxm004.homeip.net/gallery/vie...05&id=IMG_1073

Apeiron

Yes, PVC or ABS will turn into flying knives when (not if) it lets go.

Apeiron

http://www.osha.gov/dts/hib/hib_data/hib19880520.html

nick05

Weve had pvc in our shop for about 5-7 years and have had no problem with it.....just get the stuff that has a thicker wall rated at a high psi or w/e the rating is....

83 Crossfire TA

iTrader: (2)

Looking pretty good… you’ve got some nice parts there too. A couple thoughts:
- you should have plumbed the regulator so you could control pressure on both the filtered and the non filtered side… if anything, almost everything that will need the filters will have it’s own regulator…
- Probably better off putting a valve rather then a threaded plug under the drops/traps. Then just leave a bucket under it and pop it open once in a while to drain any condensation

As far as PVC/CPVC- it gets brittle with age, with use, UV exposure, chemical exposure… and when it lets go it shatters. Not a great thing to use for air because of this. There is a guy on on one of the f-body lists that had some PVC used for air shatter and he lost a few teeth, broke his glasses and ended up with an assortment of cuts and bruises, and considers himself lucky.

ABS is a different story, it tends to just let loose length wise without much fuss, there is actually air line specific ABS out there.

Apeiron

There is, but it's nylon reinforced or some such thing, and costs more than copper, I believe.

83 Crossfire TA

iTrader: (2)

As far as what I’ve seen, normal ABS is rated for air, and works fine. I’ve pressurized both to destruction and there is a significant difference how they let go. It does cost more then PVC but it’s significantly cheaper then copper, just hard to find a good selection of stuff at most “home centers”/hardware stores.

A lot of the flexible stuff that they’ve started using for water lately also makes very good air lines.

VILeninDM

I've seen few PVC debates and all of them remind me about an ongoing argument I used to have with one of my friends for years. That guy would never wear sit belts and whenever I would point it out, he'd be "I've been driving for 7 years now and never had any problems. They are too uncomfortable." That debate pretty much ended when he flew out through the windshield when a woman on a cell phone and an SUV made a left turn while he was going straight through the intersection. Somehow he walked away with minor bruise on right knee, but now every time he gets in a car, he always buckles up.

Seems to be the same thing here. People who use PVC always say they are fine and good, and then people who've used PVC and almost lost their eye tell everyone to stay away from them.

VILeninDM

thanks for the comments, 83. Yeah, I'll be changing that plug out. When I put everything together I ran out of valves but had everything else laying around.... you know how that is when it is 3am and you really want to plug a tool (any tool) and make it spin.

83 Crossfire TA

iTrader: (2)

Irockz

iTrader: (1)

I never suggested PVC,I said CPVC,there is a good deal of difference.CPVC and it's corresponding glue is rated at 400PSI,hardly a safety concern,as far as I can see.

91TPI5.7

pvc and the like are made for vent or waste lines. Most others are not intended for high pressure use

Apeiron

There's no difference. You can't use any thermoplastic piping with compressed air. The 400 PSI working strength is for liquids, not compressible gasses. It's not the pressure that makes it dangerous, it's the energy stored in compression. There's considerably more energy stored in air compressed to 400 PSI than there is in a liquid at 400 PSI, which is what makes it dangerous.

VILeninDM

plus I think the problem with any plastic is that it is more susceptible to chemicals and other stuff in the environment than copper. While the pipe is new, even 200 psi would be more than enough to contain compressed air which typically only goes to 150, but as the plastic ages at some point potential for bursting rises and it doesn't matter as much what the initial pressure rating was.

And then the second problem is safety when the burst does happen. Any pipe can break, but copper will stay in one piece, while plastic will shatter into high-velocity projectiles because plastic is not nearly as malleable as copper.

lonsal

iTrader: (2)

I'm surprised to see no one recommending galvanized steel pipe. I plumbed my shop with 1/2" galvanized. I was given the pipe free, I just had to buy the fittings and ball valves. I'd suggest including water traps and plenty of valves so you can shut down part of the system for a repair if necessary.

Lon

Irockz

iTrader: (1)

There's no difference




If there's no difference,why is CPVC twice as thick as PVC?(wall thickness)

Apeiron

There's no difference in safety, not the construction of the pipe.

nick05

A thick walled pvc like 400psi should withstand air if it is made to withstand pressurized water.

83 Crossfire TA

iTrader: (2)

There’s a reason why air tanks have their burst pressure tested with them filled with water rather then air… Water is not really compressible, air is, and because of that air holds much more energy and is MUCH more dangerous if the container ruptures.

83 Crossfire TA

iTrader: (2)

Oh, and PSI ratings are specific to the schedule and diameter. SCH 40 2” pipe will have a lower rated PSI then a SCH 40 1”. The same schedule PVC and CPVC in the same diameter will have the same PSI rating. Of course, again, that is what it’s good for carrying a non compressible liquid when not exposed to any UV light or chemicals/solvents.