1/2" or 3/4" air system?

[PoorOwner]

My 80 gallon 2 stage compressor's manifold somehow has only 1/2" NPT, I was surprised because the older model had 3/4" NPT.

Now I am puzzled, should I go with a 1/2" I.D. system with a 1/2" ball valve, 1/2" pipe, from there, or up-convert to 3/4" anyway from the tank.

My experience working on forced induction cars, says bigger is better (more flow), even if the manifold fitting has a bottle neck.. but then 1/2" is probably sized right because the discharge tube into the tank from the pump is only 5/8" or so. The compressor rating is about 16CFM @90 psi.

The garage is 20x23, at the end of the air lines, it will be plumbed to a 33' 3/8" rubber hose reel, maybe add more drops later.

Thanks

 

[1320stang]

Sounds similar to my setup. I've got a 1/2" ****** to a 1/2" ball valve, but I'm using a 1/2" NPT to 3/4" copper sweat on the other side of it.

 

[PoorOwner]

Hi, what is the solder type I should use for copper?

Do I just buy the type L or M 3/4" copper pipe from the big box stores same as what I use for water plumbing?

 

[BuickFarmer]

Manifold ? What is coming out of the tank itself. I would think 3/4 but maybe not. No matter, I would definitely run as much 3/4 black iron or copper line as you have room for. If you have the free wall space come off the tank with a flexible line to a hard line up to the top of the wall then run it down the wall at least 20 ft with drainage away from the tank, to a 1' drop with a 4 ft down pipe with a drain, then turn and go back toward the compressor, still maintaining drainage with the flow of the air. do the same thing at that end and head back toward the far end of the bldng and then that's where you'll want to put one last drain and your water seperator. The idea is to run the heated air from the compressor through as much cool pipe as possible to allow it to condensate and run to the drains where you can manually drain it ever so often. Sounds like you've got a nice compressor so do get chinchey on running the piping or else a water seperator will do you no good. I ran 3/4" black gas pipe and had no problem with leaks or anything. Will post some more diagrams when I get home from work.

 

[PoorOwner]

Hi. the manifold is a CNC block of aluminum that houses the pressure switch and the over pressure relieve valve, they cheated a bit here instead of welding another big fitting on the side pf the tank, they tapped a 1/2" NPT on this manifold as an outlet. Not the biggest deal as I said the discharge tube is probably just 1/2" I.D. copper anyway.

I am consulting this diagram it has a very good design like you described.

http://www.tptools.com/StaticText/airline-piping-diagram.pdf

I am not sure to go with copper or black iron pipe?

For now I plan to put the compressor on the far end corner near the garage door and plumb back to the front of garage for my hose reel for typical air tools. Maybe later I will add another drop near the garage door to run a hose outside for sand blasting in the driveway. Do I delibrately want to run long length for piping to collect water? If so maybe the sand blasting plan doesn't have enough pipe length.

 

[Wardrum]

If you are following the diagram in your link, note that the drops come off the main line by first going up then coming back down. I did not do this when I originally plumbed my lines and had a lot of water in the intermediate drops. After I changed it, I haven't noticed any water except in the last drop to the drain pipe. A little extra plumbing but well worth it.

"So soon so old......so late so smart"

 

[Charles (in GA)]

For some reason, a number of compressor manufacturers put 1/2 inch fittings and valves on 5 hp two stage compressors. In fact, I stopped looking at a couple of compressors (Speedaire comes to mind as one) because of this. Still, you should go with 3/4 pipe for your main line.

Charles

 

[SteveU]

Definitly go with the 3/4" over the 1/2" it will give you more surface area for cooling, lower air velocity at a given draw meaning the air will stay in the piping longer giving better cooling and will add a little bit of extra storage capacity. I used 1" pipe on mine & am very happy with it, no water problems at all where when I ran the rubber hose straight off the compressor it was almost like using a water hose. Good thing I didn't have any air tools then or it would've ruined them in short order. Price shouldn't be that much different between the two & you'll never regret having too much capacity.

 

[BuickFarmer]

I liked the black pipe because it was cheaper and imo easier than sweating copper. You can buy it at Lowes in 10 ft sticks and coulpings for the long runs then shorter sticks where you need it. use unions where you may need to add or make changes someday. I used the teflon pipe dope vs tape and have only one small leak and that is in a union. D*** unions

 

[z28toz06]

what is the part # or manufacturer of the flexible pipe that goes from the compressor to the hard line copper distribution system? can you just use one of those braided hoses they use for a toilet bowl? I looked at copper the other day and it was like 20 bucks for a ten footer, while not cheap, I should be able to do all my distribtion lines and drops for less than 200 bucks.

 

[Wardrum]

what is the part # or manufacturer of the flexible pipe that goes from the compressor to the hard line copper distribution system? can you just use one of those braided hoses they use for a toilet bowl?

Forget the toilet bowl hose. Have a rubber hose that is rated for high pressure air systems made up for your application (length, fitting size, etc.) by a reputable hose shop. If you have a Parker Store nearby, they can make one up while you wait. Mine is 3/4" dia., 450 PSI, 27" long, swivel fitting on one end, $23.00.

 

[G M]

what is the part # or manufacturer of the flexible pipe that goes from the compressor to the hard line copper distribution system? can you just use one of those braided hoses they use for a toilet bowl? I looked at copper the other day and it was like 20 bucks for a ten footer, while not cheap, I should be able to do all my distribtion lines and drops for less than 200 bucks.

I use 18" hydraulic hose for that, check the pressure rating on the hose though. You should be able to find it at farm supply places with the ends already on for around $10

 

[Lu47Dan]

3/4" Steel or copper is fine , All threaded fittings should be teflon taped and doped , buy good dope not the cheap gray dope . I use Loctite 545 on all my Pneumatic (Air) and Hydraulic fittings , it is not cheap , but a 50ml. bottle will do all your joints on a small system . With 545 you DO NOT need teflon tape , and it is made for air systems .

 

[kartracer55]

Use this chart


http://www.airheads.net/tech/techinfo/airline.html

Jim

 

[bmwpower]

I just went to Home Depot the other day and stopped by the copper isle.... a 10 stick of 3/4" copper was close to $50...ouch. That may make the decision for me much easier.

 

[bmwpower]

3/4" Steel or copper is fine , All threaded fittings should be teflon taped and doped , buy good dope not the cheap gray dope . I use Loctite 545 on all my Pneumatic (Air) and Hydraulic fittings , it is not cheap , but a 50ml. bottle will do all your joints on a small system . With 545 you DO NOT need teflon tape , and it is made for air systems .

This sounds like a good idea. Is it thick? Does it flow like regular loctite? Does it harden?

I bought some other stuff while I was a Home Depot the other day. It's white, contains teflon and it rather messy. It doesn't seem to harden either.

 

[BuickFarmer]

The pipe dope with teflon is what I used... no tape and no leaks.

 

[kartracer55]

BMW, Yeah the copper is expesive BUT look at it like this...

If you try and save$ on the copper in a smaller size, you may run into air delivery problems.

The drawback to galvanized/blackpipe is that unless your running an air drier and have almost perfectly dry air, you will need to have a filter at every drop right before the hose, because scale will flake off from inside and get into your tools. Right now we only have 2 drops, but will be adding 2-3 more when we go ready to plumb air into the basement this spring. Buying 3-4 additional filters at about 55$ a piece would have wound up costing essentially what copper did. It just made more sense to use copper because there were no threaded connections to deal with and we could cut every length of pipe to size without having to go get it threaded.

Jim

 

[Bib Overalls]

The only problem with black pipe is cutting threads. The Lowe's and Home Depot stores here will cut the threads for you for free in 10" lengths. But you really have to fit and measure. So some times I have actually taken pipe home, cut it to length, and gone back to the stor to get the threads cut. I use a professional pipe cutting tool. Also, you need to check with the store before you cut because there machine will not thread lengths of pipe if they are to short.

 

[PAToyota]

I just went to Home Depot the other day and stopped by the copper isle.... a 10 stick of 3/4" copper was close to $50...ouch. That may make the decision for me much easier.

Hmmm...

Just last week I picked up ten pieces of 10' x 3/4" L copper pipe at Lowes for just over $20 a piece... Maybe I should go back and buy them out if the prices are rising again?

 

[Alex]

The only problem with black pipe is cutting threads. The Lowe's and Home Depot stores here will cut the threads for you for free in 10" lengths. But you really have to fit and measure. So some times I have actually taken pipe home, cut it to length, and gone back to the stor to get the threads cut. I use a professional pipe cutting tool. Also, you need to check with the store before you cut because there machine will not thread lengths of pipe if they are to short.

Just finished running the main lines, 3/4" black pipe, yesterday. I already had a heavy duty Rigid pipe cutter and I sprung for this Harbor Freight Pipe Threader ( Item # 30027. $19 at the retail store).
I know ,before anyone rips me about Harbor Freight, it is what it is. The threader finished the job, it cut the threads with ease, nothing broke, I could use it again (maybe) then loan it to someone, never get it back and the tool will not owe me a dime.

 

[bmwpower]

Hmmm...

Just last week I picked up ten pieces of 10' x 3/4" L copper pipe at Lowes for just over $20 a piece... Maybe I should go back and buy them out if the prices are rising again?

What?!?!?!??!!? 1/2" isn't even that much. I think 1/2" is around $23-28, IIRC. Which Lowes did you go to? I can't remember where you are in PA.

 

[PAToyota]

Harrisburg, PA store. Got a flyer in the mail with a barcode coupon good until the end of the month. But even without the coupon the price was only $22~$23 or so...

 

[1fastvx]

So its safe to use 3/4 Type-L for air lines? I always thought you were supposed to use Type-K?

Thanks for the info,

John

 

[bmwpower]

Harrisburg, PA store. Got a flyer in the mail with a barcode coupon good until the end of the month. But even without the coupon the price was only $22~$23 or so... You can see 1/2" type M right above it for $9.04...

I just took a look at the flyer (2/19 week) online and didn't see anything about copper. Did you already use the coupon? If not, any chance I could? I was thinking maybe I could take it into my local Lowes to see if they will price match.

 

[PoorOwner]

I will be going with copper, anyone know if 95/5 Solder is something that can be bought at home depot / Lowes as well?

 

[kartracer55]

So its safe to use 3/4 Type-L for air lines? I always thought you were supposed to use Type-K?

Thanks for the info,

John

Yes my entire system was done in Type K. Most people do it in this, and in fact, alot of people do it in Type M. I just went with K myself.

 

[PAToyota]

Yep, 95/5 is available at Lowes. Technically it is type M that you aren't supposed to use for air piping, but if you look at the pressures in the Copper Handbook even it will hold the pressures that we are using.

The coupon is good until the end of the month - you can keep using it until the time is up. I'm planning on using it again Tuesday evening.

I checked the online prices for Lawnside, NJ and Harrisburg, PA. They don't have the 10' lengths online, but the 3/4" ID x 60' Type L Copper Coil is $161.87 both places. I wonder why the 10' lengths are so different? PM me and I'll scan the full page and the coupon and e-mail it to you. Not sure if they'd honor a price match or not?

 

[kartracer55]

I will be going with copper, anyone know if 95/5 Solder is something that can be bought at home depot / Lowes as well?

Yes. It is easy to find, Oatly makes it

 

[z28toz06]

I just priced grade m and l 3/4" copper Friday night and it was 21 and 23 dollars per 10' length. home depot

 

[63Chevy]

I just priced grade m and l 3/4" copper Friday night and it was 21 and 23 dollars per 10' length. home depot

I keep getting the L and M mixed up but one of them was $15.24 for 10ft at HD just last week. I wanna say it was L and M was around $20.28 for 10ft.

Either way they both should work. According to that Copper Handbook..

L @ 150F for 3/4 = 495psi
M @ 150F for 3/4 = 346psi

I dont know about you guys but my compressor only does 150psi so your over double even with the M pipe.

 

[bmwpower]

You are all correct. I must have seen the copper right before the price change. I was in a Lowes in PA, probably over a week now, and it was definitely likr $48 for a 10ft of 3/4".

I stopped in Home Depot near me tonight and sure enough the prices have dropped. I think it was like $20.** for 3/4" L 10 foot.

Is this the lowest it's been? Should I buy now cause it's low?

 

[PAToyota]

I keep getting the L and M mixed up but one of them was $15.24 for 10ft at HD just last week. I wanna say it was L and M was around $20.28 for 10ft.

M is the "lowest" grade - thinnest wall - so it would be the cheapest. Then L and then K. So it sort of goes backwards.

Is this the lowest it's been? Should I buy now cause it's low?

I'm stocking up to finish out some things. But it's like gas prices. Just when it drops $0.05 and you tank up you see it for $0.08 less the next day. Yet if you hold off it ends up going up $0.12... Who knows? I figure that I can afford to buy it at this price and do what I need to do and better get it done before it goes back up again... I do think that the supply is catching back up to the demand. But I sort of doubt that it is going to go significantly lower than where it is at now. You might see a buck or two cheaper, but I doubt you're going to see it $10 cheaper...

 

[PoorOwner]

I want to buy some parts soon for my copper 3/4" system but I wanted to know if I you guys have used NPT threaded ball valves for the drop, or sweatable ball valves, I assume the latter is more espensive (Ez sweat style?)

Is it a pain, converting the copper ends to NPT and ball valve to another NPT adapter again?

Also why do people do 3/4" main and 1/2" drop? The cost isn't that much more to do 3/4" to the outlet is it? with a proper riser off the main line and riser again off the drop that's where I see will have most elbows and therefore restrictions so why not use 3/4" all the way?

Although I am probably only going to have 2 drops so it's not as espensive like every 6 ft around the "shop"

 

[fefarms]

Threaded and sweat ball valves are about the same raw cost. Since you'll need to incorporate adapters to go from copper tube to NPT, the threaded ball valves cost more, and are more work. Then there are issues of leaks, and getting the NPT connections tight enough.

I've tried the "Easy Sweat" ball valves, thinking they'd act as both a shut-off and a union. But they seem to be a bit fragile, and tend to leak. I just buy regular sweat ball valves now.

You can do 3/4 drops, I've done it that way in the past. The main reason to go with smaller drops is economy. One additional consideration is that you need to drop down from 3/4 sweat to 3/8 NPT or 1/4 NPT for your quick connects. You need less bushings/reducers to do this if you drop from 3/4 to 1/2 at the mainline take-off. You are looking at maybe 3 elbows and a branch tee plus 4 feet of drop pipe -- maybe 20 equivalent feet of pipe. At 3/4 inch the pressure loss of the drop is 0.25 PSI at 40SCFM. Completely negligible.

For a 1/2 inch drop it would be about 5X this or 1.25 PSI. Pretty acceptable loss, still, considering that's 40 SCFM, which is a lot of air to take off one drop pipe in a home shop.

 

[PAToyota]

I'm sweating everything else, so I just sweat the valves as well. I see no reason to go through the conversion to threads and back again... Mine is all in 3/4" pipe, but sometimes the smaller drops work better for fitment.

 

[1fastvx]

I have another question for you guys. I have seen the TPTools digram and want to do my setup like that in copper. Does anyone have any pictures of how they ran the drops off the main line? In the TPTools diagram you want to go something like 8+ inches up before coming down. How do you handle the spacing off the wall since the pipes will have to cross each other coming back down from the 8 inch upwards section?

Thank for the info!!

John

 

[Junkman]

I have another question for you guys. I have seen the TPTools digram and want to do my setup like that in copper. Does anyone have any pictures of how they ran the drops off the main line? In the TPTools diagram you want to go something like 8+ inches up before coming down. How do you handle the spacing off the wall since the pipes will have to cross each other coming back down from the 8 inch upwards section?
Thank for the info!!

John

Here are two items that I have used in the past when doing water plumbing. Everything for water is the same as for air. These are available at plumbing supply houses, and the brand that the prictures come from is Elkhart Products. You can find other useful items that will save you both time and money on the website...

 

[bmwpower]

Here are two items that I have used in the past when doing water plumbing. Everything for water is the same as for air. These are available at plumbing supply houses, and the brand that the prictures come from is Elkhart Products. You can find other useful items that will save you both time and money on the website...

That one is great to use instead of all the separate pieces at the top of the drops. Good find, Junkman!

 

[fefarms]

If you are careful, you can use a conduit bender for the same diameter EMT to make the drop pipe conform to the wall. Another option is to use Pex-al-pex tubing, which can be bent in your hands to the shape you need, and it holds the shape. 1/4th the price per foot of copper.