Confusing copper fitting labels

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Old 08-27-16, 12:51 PM
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Confusing copper fitting labels

Hello everyone. I'm preparing to purchase all the copper fittings and pipe to assemble a garage shop air line system for spray painting, and air tool use. I intend on sweat soldering most of the fittings, except at maybe the ball valves at the regulators/filters. But that remains to be seen. However, here is my problem.

I just finished my parts/quantity's list and started looking online at Home Depot, to price the entire system. As I looked at the various fittings, some things became apparent. I don't know what the various terminology means. I'm looking for simple sweat fittings, but whoa! There are so many different terms...I thought I better get informed a bit.

For instance, there were 3 or 4 different versions of the various fittings. Some had the term "pressure", and C + C...and FTC and on and on and on. So, can someone tell me how to tell which are for simple sweat soldering?

Also, I'm reluctant to solder ball valves, vs using compression fittings or other options. Any opinions? This whole thing is about MOOLA. I need to save as much money as I can, as I'm retired and on a fixed SS income. Hence using sweat fittings vs other stuff...like those Sharkstooth or what ever. Anyway...any help would be greatly appreciated. Thanks
 
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Old 08-27-16, 01:13 PM
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I need to go out for several hours but I wanted to get this out...soft-soldered copper for compressed air piping is generally not recommended. It may even be prohibited in some jurisdictions. I personally recommend using threaded steel piping. Above all, NEVER use PVC piping with compressed air.
 
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Old 08-27-16, 01:42 PM
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I second Furd's comments on using iron pipe. Easy to put together, solid and no leaks if done right.
 
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Old 08-27-16, 04:34 PM
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Copper would be by far the most expensive way to do it.
Copper forms a green slim inside of it that will go right through a filter, and will react with any metal other then copper and pit it.
Use black iron pipe not galv.
Keep in mind a 3/4 pipe will have about twice the flow of a 1/2 pipe, want containt pressure you need the flow.
Makes a huge difference on how the piping is ran if you want to keep water out of the lines.
https://www.google.com/search?q=air+...puZrqEC0gjM%3A
Make sure you use ball valves not gate or globe valves!
 
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Old 08-27-16, 06:02 PM
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Copper and fittings can be used for compressed air air but not the type "M" commonly found in hardware stores.
It must be type K or L copper and must be brazed.
Solder is not appropriate.

Threaded black iron pipe or specially rated plastic fittings designed for air are also ok.
 
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Old 08-27-16, 06:54 PM
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It must be type K or L copper and must be brazed.
Solder is not appropriate.
I agree with K or L but soldered with silver solder is fine...

A soldered joint is good for some 400 psi or more. Pro press 200 max. Shark bit probably the same/...

For the cost though threaded pipe is your best bet. I understand your dilemma though. You must cut and thread to size. You will need a threader or have the home store cut the lengths you need...
 
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Old 08-27-16, 07:52 PM
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Old 08-28-16, 01:04 PM
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Holy moly. So many replies in one day. Ok, let me say this. I've read more about air lines in the last month than I can remember. The thing that stands out mostly though, is there is so much conflicting opinions. As for iron pipe...it's rust. As for plastic..it'll kill ya. As for copper.. it creates slime. And that's the first time I've heard of that.
Ok,now I'm really confused. All I know is the various "systems" are very expensive. At least the fittings. I chose copper, basically because of all the recommendations on the net. And, I'm a NASA certified solder jock. More over, because of the design of my system, and the distance to any place that carry's it, let alone custom cutting and threading, iron pipe and fittings are out of the question. Here's a few Sketchups and you'll see why.

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And that's not all of it. So.... regardless of slime, which I've never heard of, and, considering I have filters, I'm not worried about, I'm sticking with copper. Which brings me back to my original question. Those lables. How do I tell which are regular old sweat type fittings?
 
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Old 08-28-16, 02:56 PM
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Read this.. It will answer all your questions hopefully...

https://www.copper.org/publications/...e_handbook.pdf
 
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Old 08-28-16, 09:13 PM
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I was involved with compressed air systems for most of my career and I never saw any kind of "green slime" from copper piping EXCEPT when we used a specific coolant/lubricant in rotary screw compressors. This was caused by excess oil carryover from the compressors and when the special fluid was replaced by a straight mineral oil AND the air/oil separators on the compressors were upgraded (under warranty) the problem disappeared except for some instrument air piping that was never flushed. Opening a valve positioner caused the slime to foam up and it looked like Edge shaving gel.

Copper CAN be a good material for compressed air piping and there are thousands of miles of it installed in instrumentation systems. BUT, it is not lightweight (type M) and it is NOT usually soft-soldered. Use compression fittings or use a hard solder such as Phos-copper and you won't have any problems.
 
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Old 08-29-16, 03:15 AM
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Hi guys. Cool. I appreciate the info. I'll check out the PDF asap. Btw, as usual, on a couple of other forums, there were plenty of opinions saying use Type M and be done with it. Even using 50/50 solder. Hahaha. Never ceases to amaze me. But I'll go with the hard stuff. I like the hard stuff. Like 100 proof vodka.
Ok guys, thanks again. Time to get this done. As FURD might remember what I went through to get the electrical part of the equation figured out. STILL haven't finished that one. Got all the quad breakers, and the panel, but no time. Too many irons in the fire...like this one. Which I'm building at the same time.
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Ok..I'm outta here. Thanks again
 
 

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