Hose size and connects for air tools

[Keith Downing]

So, the saga continues on my compressor install, plumbing in the lines and getting ready to run.

I'm doing the 3/4 maxline, as previously discussed, which I like (although it does seem huge going up).

I also went to the trouble of getting the 1/2 npt to 3/8 quick connect couplers for 3 of the 5 outlets to increase air flow for certain tools and spray guns.

But....now I'm finally looking at hoses and almost everything I find (even if it's 3/8 inch hose) has 1/4 npt brass connections. The local big box stores don't even seem to carry 3/8 connects on any hoses.

Did I make a mistake? Am I looking at the wrong type of hose?

Every time I think I have everything planned out I feel like I get thrown a nasty curve ball. LOL

[Ronald Blue]

Go to an industrial supplier and they should be able to fix you up. Possibly Fastenal or Grainger or something similar.

[Keith Downing]

Thanks. I will check with some more places tomorrow.

I'm not wrong in thinking that a lot of the high end spray guns and pneumatic tools will have a 3/8 connection though, am I?

[John K Jordan]

I don't know about high end use, but I use 1/4" quick connects on all of my air tools and it seems like enough air to me. For example, I have a couple of good air impact wrenches I use for vehicle and farm equipment maintenance. To get to the outside of the shop I run about 50' of 1/2" air line through the walls to an air line reel with 50' of 3/8" line with a 1/4" fitting connecting the air tool through a short pigtail hose. I seem to have plenty of air to loosen any bolt I've attacked with an impact wrench. I also use air operated needle scalers, die grinders, and other air tools with this line. I use the 1/4" fittings on all my nailers and staplers too, usually on very long flexible air lines.

I suspect industrial applications may need more air volume but for a home and farm shop the 1/4" may be enough. As for the 3/4" plumbing, if I had installed that in my shop I would have no regrets! Air lines, water pipes, wire sizes, chains, and ropes are usually far better too big than too small! This way you can take advantage of bigger fittings where needed, perhaps for a grit blaster.

JKJ

[Justin Ludwig]

Spray guns are going to be 1/4" npt. They operate on 35-50psi and 5-10 CFM. NPT sizes can be confusing because they are nominal sizes. Go to an auto parts store and look at nipples and unions of 1/8, 1/4, and 3/8. You'll see what I mean.

Dont to forget to install an inline dryer and air filter.

[Mike Heidrick]

New shed will also be 3/4 Maxline and will put a regulator at each drop. I will Go 1/2" to the regulator. There may be a manifold after each of those regulators. I am using Milton V quick connect fittings that will accept the 1/4" M and the high flow 1/4 V fittings. All my pneumatic tools are 1/4". The pneumatic Kreg Foreman came with a high flow fitting.

[roger wiegand]

Originally I did all 3/8" hoses and fittings. After a while I got tired of the big heavy hoses and big clunky connectors unbalancing every tool and tried switching over to lightweight polyurethane hoses and 1/4" fittings. I've never looked back. For my uses there is no detectable difference in performance and they are 50x more pleasant to use.

[Rick Lizek]

1/4" is fine unless you are using a jack hammer for breaking up pavement. Been in small shops and big commercial shops for 40 years and 1/4" is the standard. You didn't do your homework thoroughly and what you are doing is overkill.
https://cached.tptools.com/Images/airline-piping-diagram.pdf
This is how to run your airlines. Drops go up then down. Lines should be pitched toward the tank. I've been in so many shops that set up their airlines wrong and had constant water problems.

[Erik Loza]

I don't know about high end use, but I use 1/4" quick connects on all of my air tools and it seems like enough air to me. For example, I have a couple of good air impact wrenches I use for vehicle and farm equipment maintenance. To get to the outside of the shop I run about 50' of 1/2" air line through the walls to an air line reel with 50' of 3/8" line with a 1/4" fitting connecting the air tool through a short pigtail hose. I seem to have plenty of air to loosen any bolt I've attacked with an impact wrench...

That's interesting. I have a 30 gallon compressor and previously had one of those coiled 1/4" poly lines. Always felt like my 1/2" impact gun was underpowered. At least as compared to friends' that I had used. Decided to switch one day to 3/8" line and it was a night-and-day difference. That being said, the 3/8" hose is a lot more hassle but I can break axle nuts easily now. Maybe my compressor size has something to do with it.

Erik

[Marty Tippin]

It's only my opinion, but it seems to me you're trying to solve problems you don't really have or at least haven't confirmed that you really have. The 3/4" Maxline is definitely pretty but unless you've got a big shop with multiple air tools running at once, I can't imagine it's necessary. Same with the big fittings - if it was really necessary, every tool wouldn't have 1/4" fittings.

I run a 3/8" hose on my hose reel (and I believe most folks do also), but it has the standard 1/4" fittings. My supply line is the 1/2" RapidAir stuff, made by the same folks who sell Maxline. I'm quite happy with it and, for my one-man hobby shop, I haven't found any limitations that I can blame on either the size of the supply line or the 1/4" fittings on the end. My 1/2" impact gun breaks the lug nuts loose on all my vehicles, even at the end of 50+ feet of 1/2" RapidAir and a 50 ft hose with 1/4" connectors on the end...

It's your shop and your money, of course, so feel free to spend as much as you want to make yourself happy!

[Mike Cutler]

Keith

One of the issues that you're running into is "standardization". Larger shops will standardize tool fittings and and airline fittings so that any tool can be plugged into any fitting, without any additional adaption.
In a perfect world, a 1/2" fitting would always allows more airflow than a 3/8" fitting, but ultimately the airflow is determined by the internal orifice restriction of the ball check valve.
Certain tools require a lot of airflow, sprayers, sanders, large grinders, needle guns, air driven pumps, etc. Most of the common tools that you expect to see in a home garage don't really take as much airflow, ratchets, impact guns, air, small grinders etc. I would venture to say that most of the tools in a home garage setting will run just fine off a 1/4" npt end of line fitting adapter. The internal orifices of the tools are smaller than than the orifice restriction of a 1/4" NPT fitting adapter.
One thing that can make a difference is the actual air hose itself. Cheap air hoses have thicker walls for a given pressure rating. The smaller the internal diameter of the air hose itself, the higher the friction, which can decrease flow.
I think you're fine. plug your tools in and resolve any issues once you find them

[Ronald Blue]

You won't regret the 3/4" supply line even if it is over kill. You won't ever think to yourself is this tool starving for air. I think what's being missed here is that air is like fliud is like electrical current. Each tube size or wire size has a maximum amount that it can handle. The 1/4" couplers will likely handle most any of your tools. It's good for 13 cfm at 100 psi. However that drops to 5.5 cfm at 40 psi. Just as a reference though moving up to only 3/8" increases that to 29 cfm and 12 cfm respectively. More than double. Another thing is that through normal friction in the line or resistance is that in a run of 100 feet you will see a pressure drop of 10%. Since you are running 3/4" inch main line that loss is only 5%. This can be a factor in some applications. Mike's plan to have a regulator at each drop is pretty wise thinking. Full line pressure to the point of use and then regulate output for the tool requirements. Look at all your air tools supply requirements and if they don't exceed the 1/4" coupler ratings then your good. If you have something that demands more then you have some options on how to meet that need.

[Jim Becker]

I use light-weight and very flexible polyurethane hoses (Flexeel) and 1/4" NPT fittings. I've never felt a need for heavier stuff. The exception might be if I had to run a hose to the house for some reason, but I have a small, portable compressor for little "on-site" jobs.

[Tom Ewell]

Went through the same thing in my shop.
Ended up plumbing with 1/2" from compressor to stations but I have fairly short runs.
Use 3/8" Flexzilla from the stations.
The compressor is regulated at full go, if I need to regulate at a station, I use a regulator setup with male/female connects to snap onto the station outlet and hose.

I'm sure I could optimize it some but my setup does what I need it to do, the only time I've had to let it catch up a little was using a pneumatic wet ROS for extended time color sanding some auto clear coat.

[Keith Downing]

My new plan is to go ahead and move to the 1/4 connects on everything with the exception of 1 plug in the shop (for any future tools that might need it) and 1 plug heading outside which will eventually lead to a paint booth which will have a secondary filter/dryer.

Thanks for the input guys. For the most part it was very helpful.

[Mike Cutler]

My new plan is to go ahead and move to the 1/4 connects on everything with the exception of 1 plug in the shop (for any future tools that might need it) and 1 plug heading outside which will eventually lead to a paint booth which will have a secondary filter/dryer.

Thanks for the input guys. For the most part it was very helpful.

Keith
I think you're going to be very happy over the long term with everything you've done, and your material choices.
It's always easy, but time consuming, to cobble together something that "works". Doing it right from the beginning, as you have, will pay dividends down the line. ;)

[Keith Downing]

Thanks for the kind words Mike. That's exactly what I was going for, a system that performs well and i won't ever need to upgrade.

So many of my setups I had to piecemeal together and ended up frustrated. Finally had the time and $ to do a project right from the start and I wanted to make sure I did!

[Chris Parks]

I have 3/4" lines supplying 3/8" reels @ 110PSI. That setup should supply adequate air for impact guns in theory but in practise it is totally inadequate. I start using the tool and I can see the performance dropping off and what is really apparent is the hose up to the tool relaxing as the pressure drops. I suspect a short run of 3/8" would be adequate but wrapped around a reel it is woefully poor in performance.

[Tom M King]

Chris, how much air does your compressor move? I use a 1/2" air impact wrench through 200' of 3/8 hose that mostly stays on a reel, and it does fine. All fittings and quick-disconnects are 3/8" (hose ends may be 1/4"NPT-It's been so long since I've noticed them that I don't remember). I don't remember the cfm of my compressor but it's a 7-1/2 hp two stage. Shop hard lines are 3/4" too. Regulator is on the 80 gallon tank before all the lines. That setup is close to 40 years old with some parts replaced over that time. I've never been in want of more air for anything from spraying to running air grinders and impact wrenches.

[Chris Parks]

Tom, it is a 15CFM pump set to 110 PSI cut off. For a short run to apply or remove a standard nut it is OK but if I have to run it for 15 seconds or so to remove stuck or seized fasteners it falls over. I was driving in 200mm 14G screws into pine the other day without pre drillling and it was very noticeable. I am sure it is the reels because before I installed them I did not encounter the problem and it is either the hose wrap or the entry/exit fittings on the lines. I think the reels are going to get ripped out and 1/2" fitted which annoys me for the cost is quite a bit more.

[Tom M King]

Yeah, probably a bottleneck in there somewhere. I wish I could get another reel like the one I have, that I bought new in the mid '70s. The air inlet is a 3/8 male quick-disconnect on the end of the first hose. The swivel is just the female quick-disconnect. The male end is right where the end of the shaft the reel rotates on would be. On the other end is a square piece that a removable handle fits on. I've replaced that female fitting once in 40 years. There is no bottleneck anywhere in the system. The two 100' hoses where bought from Senco, where the reel came from, way back then. They've been used almost daily with no repairs needed to the hoses-can't buy them like these any more either.

[Mike Cutler]

Chris

Hoses wrapped around a reel will naturally create a pressure drop due to friction. The tighter the coil the more the effect. It still shouldn't be as significant as you're indicating. Those reels are used everywhere.I agree with Tom, somewhere in that hose reel is an internal orifice that is being restricted.
Something is definitely not right and I would look at the quick connects to see if they were properly installed and haven't caught a flap of hose in the crimping process, to make them, which might be the restriction.
Have you uncoiled the entire reel to be sure that the hose isn't twisted? One more trick to try is to pull the entire length out, let it pressurize than reel it back up pressurized. make sure that the initial few inches of hose on the reel, the inner coils, are not being flattened by the rest of the hose once it's pressurized.

[Keith Downing]

Ok, finally got everything plumbed in. For those wondering the maxline was about what I expected. A little easier than copper for the basic install, but a few things took me more than one try to figure out how to do efficiently. I will say that if aesthetics are important to you (perfectly straight tubing, perfect right angles at T's and L's) plan to spend about an extra half day on the install. This stuff is a bear to get perfectly straight.

ONE MAJOR QUESTION: the maxline all sealed really well, but a lot of the other fittings, quick connects and drain valves are leaking slightly at the point they connect to the aluminum outlet block. Doesn't matter how much I tighten them.

Did I not use enough teflon tape? Did i possibly over-tighten? I let the guy at home depot talk me out of using any kind of glue or loctite on them. Is there a quick fix like that for up to about 125 psi?

[Tom M King]

I remember having to keep playing with some of the high pressure side fittings on my setup back in the early '90s. I ended up using Teflon tape and some sort of Oatey pipe sealant together to ever get it to top leaking 100%. I haven't had to touch it since then, and don't even remember thinking about it before this.
You can get it in the plumbing section of the box stores, or I'm sure Amazon too: http://www.oatey.com/products/thread-sealants/pipe-thread-sealants

[Tom M King]

I had never seen Megaloc before searching for that link, but I think I need to get some of that. http://www.oatey.com/products/thread-sealants/pipe-thread-sealants/megaloc

http://www.amazon.com/Oatey-15804-Hercules-Megaloc-Multi-Purpose/dp/B000BQ8DUW/ref=sr_1_2?ie=UTF8&qid=1459735334&sr=8-2&keywords=megaloc

[John K Jordan]

I had several leaks on the first couple of outlets I installed (8 outlets total), checking everything with soap solution (I used kids bubble solution). Several were where I used some sealant goop instead of tape. I took all leaking connections apart, cleaned the threads, and wrapped with two layers of good teflon tape. Tightened until the leaks just quit. As you experienced, my plastic pipe connections all sealed perfectly. I used the smaller 1/2" RapidAir system.

BTW, where possible on subsequent outlets and fittings I built everything on the bench, pressure testing as I went. (I made a test fitting with a quick connect, valve, and a section of the plastic pipe. For each test I cut a little off the end of the pipe to provide a clean end.) With this method I had no more leaks.

JKJ

[Keith Downing]

I'm really tempted to try something like the megaloc. First, I don't want to do this a third time if I have to take it all apart but also some of the connects don't land on center (straight vertically) when fully tightened. It'd be nice if I could use a thread sealer and stop at 90% tight when I need to.

On the flipside, if it doesn't work as advertised I could very well have a mess on my hands.

[John K Jordan]

some of the connects don't land on center (straight vertically) when fully tightened. It'd be nice if I could use a thread sealer and stop at 90% tight when I need to.

I don't remember if it was Megaloc sealer but the only time I had problems was with with a non-hardening brush-on sealer. Maybe I tightened it too much or didn't let it set up long enough. I gave up on it.

i'm certainly no expert, but I'm wondering if you are tightening too much when you said "fully tightened," I have never tightened a fitting so much that it wouldn't turn any more - there has always been enough play to turn enough more to get the parts to align. I apply several layers of good teflon tape then tightenen until the parts were aligned then tested. It was a judgement call whether to quit at some point or to make one more turn, but I don't temember ever tightening to the point where it couldn't be turned further.

I never had leaks with tape on brass and aluminum, but I think I had one connecting cast iron to cast iron that I had to take apart and use more tape. Oh, some of the tape I had was thinner so I wrapped a little more. When I had to redo one I was careful to remove all the old tape or goop.

I'm guessing, without counting, that I made at least 100 connections in my shop with all the outlets, dryers, regulators, manifolds, and valves. But like I said above, I'm no expert and just learned as I went. Maybe someone who does this for a living will advise or you might ask a contractor who does this for a living or find on-line advice. Or practice with some fittings on the bench to get a feel for how much tightening is needed to seal.

JKJ

[Keith Downing]

I don't remember if it was Megaloc sealer but the only time I had problems was with with a non-hardening brush-on sealer. Maybe I tightened it too much or didn't let it set up long enough. I gave up on it.

i'm certainly no expert, but I'm wondering if you are tightening too much when you said "fully tightened," I have never tightened a fitting so much that it wouldn't turn any more - there has always been enough play to turn enough more to get the parts to align. I apply several layers of good teflon tape then tightenen until the parts were aligned then tested. It was a judgement call whether to quit at some point or to make one more turn, but I don't temember ever tightening to the point where it couldn't be turned further.

JKJ

I have a suspicion this may be the problem as well. I'm going to try the worst offending outlet again with the teflon tape, laying it on pretty thick, and we'll see what happens.

[CPeter James]

One problem with teflon tape and some fittings is that it makes things turn too easy and the tapered fittings crack. I learned about this many years ago when I was installing chemical dispensing equipment. I like Rectorseal. I have had great luck with it over the years.

PEter

[Marty Tippin]

I used the Oatey pipe thread compound on all my threaded air fittings and don't have any leaks anywhere. Started out trying to use teflon tape but it wouldn't seal. It's a cheap and simple fix.

[Keith Downing]

One problem with teflon tape and some fittings is that it makes things turn too easy and the tapered fittings crack. I learned about this many years ago when I was installing chemical dispensing equipment. I like Rectorseal. I have had great luck with it over the years.

PEter

Yeah, I think that combined with the extra "give" from the aluminum is making this especially tricky.

[Keith Downing]

I used the Oatey pipe thread compound on all my threaded air fittings and don't have any leaks anywhere. Started out trying to use teflon tape but it wouldn't seal. It's a cheap and simple fix.

Are you putting the pipe thread compound directly on the pipe, or applying teflon tape and adding the compound on top. The latter seems to be the common way most do it.

[Marty Tippin]

Are you putting the pipe thread compound directly on the pipe, or applying teflon tape and adding the compound on top. The latter seems to be the common way most do it.

No teflon tape anywhere. Lather up the threads with pipe thread compound and assemble. Just like you'd do for black pipe.

Also a correction to my previous post, I actually used RectorSeal #5 product, not Oatey.

[Tom M King]

I had to go into Home Depot today, so I looked at the thread sealants they had on the shelf, remembering this thread. What I was talking about doing to stop 175 psi leaks earlier in the thread was also done with Rectorseal. I read the specs on it, and it says up to 100 psi. When Teflon tape wouldn't stop the leaks back then, I put Rectorseal on the threads, Teflon tape over it, and put Rectorseal in the female threads too before screwing the fitting in. I'm not saying that's the only way to do it, but I remember being frustrated with it, and trying belt and suspender approach. I don't think I tried the sealant by itself.

In spite of the pressure rating of the Rectorseal, my old compressor will still hold at 175 psi until I use enough air for it to kick back on. I try to remember to flip the breaker for it when I'm going to be away from that shop for a while, but don't always do it.

[Marty Tippin]

I read the specs on it, and it says up to 100 psi.

No, RectorSeal is rated for gases up to 2600 psi.

The 100 psi you're referring to is the maximum pressure it's rated for immediately after assembly before it's had time to cure.

http://ows.rectorseal.com/product-data/rectorseal-no-5/dsno5.htm

[Tom M King]

No wonder mine is still holding! They also had this stuff in Home Depot today. It has interesting reviews, and might be what I would choose today. Rectorseal is a bit messy to work with, and not that easy to clean up behind. http://www.homedepot.com/p/RectorSeal-4-oz-Tru-Blu-Pipe-Thread-Sealant-with-PTFE-31630/203490732

[Ronald Blue]

I don't remember if it was Megaloc sealer but the only time I had problems was with with a non-hardening brush-on sealer. Maybe I tightened it too much or didn't let it set up long enough. I gave up on it.

i'm certainly no expert, but I'm wondering if you are tightening too much when you said "fully tightened," I have never tightened a fitting so much that it wouldn't turn any more - there has always been enough play to turn enough more to get the parts to align. I apply several layers of good teflon tape then tightenen until the parts were aligned then tested. It was a judgement call whether to quit at some point or to make one more turn, but I don't temember ever tightening to the point where it couldn't be turned further.

I never had leaks with tape on brass and aluminum, but I think I had one connecting cast iron to cast iron that I had to take apart and use more tape. Oh, some of the tape I had was thinner so I wrapped a little more. When I had to redo one I was careful to remove all the old tape or goop.

I'm guessing, without counting, that I made at least 100 connections in my shop with all the outlets, dryers, regulators, manifolds, and valves. But like I said above, I'm no expert and just learned as I went. Maybe someone who does this for a living will advise or you might ask a contractor who does this for a living or find on-line advice. Or practice with some fittings on the bench to get a feel for how much tightening is needed to seal.

JKJ


You have never dealt with high pressures then if you don't tighten your fittings tight. Actually there are so many options superior to pipe for high pressure but with air lines and the related couplers we are pretty well stuck with pipe threads. I agree that you have to be careful with aluminum and brass fittings, manifolds, etc in that you can easily split them by over tightening. You have received lots of good advice so there isn't anything I can add without being redundant. Let us know how it works out.

[Keith Downing]

Ok, here's how it all worked out for me over the last 3 days....

For those who don't like to read, here are the Cliff's notes: On the aluminum blocks and manifolds the better teflon tape + the megaloc finally got the job done.

I last left off here settled on ordering some more cheap teflon tape and the Megaloc thread sealant. Was going to try really thick tape jobs vs the megaloc. Of course, the shipment was a day late and I got an order I wanted to use my sprayer for so I went down to the big box store to see what they had.

As usual, I knew more than the guy working the plumbing aisle. So, without any help I went ahead and made a big investment in the $3 Oatey Fastape (pic below). Tried it on all the joints that were noticeably leaking. It was definitely a step up from the $1 teflon tape. Felt more like a light rubber once I got it on the threads and rubbed it a bit.

So, I finished everything out and did a pressure test. Couldn't hear any hissing. Closed the valve on the compressor and still couldn't see any immediate pressure drop. Unfortunately, I came back an hour later and the secondary regulator gauge on the maxline read zero. Failed again.

Started in with the soapy water test on all the connections. I found dabbing a q-tip works much better than spraying the soapy water like I've seen others do btw. Nearly every single connection TO THE ALUMINUM BLOCKS was still leaking. I don't believe I found any brass on brass or brass on quick connects leaking after the thicker application of the better tape. Decided to give up for the day and just get my work done.

After a couple of days, I had the Megaloc and decided to see how it worked. So, I took apart and stripped down my worst offending outlet (has an aluminum block AND an aluminum manifold with 4 connections, you can see it in the pic). Now, there aren't real thorough instructions with the Megaloc, which kind of looks more like a paste than a glue. Just says to apply to clean male threads. No mention of how thick, or whether to leave or wipe away any excess at the mouth of the connections after they are tightened. I put it on generously but not too heavy. As I threaded the pieces together there was PLENTY of megaloc coming out of the receptacles. So I know I wasn't putting it on too light. And I got everything nice and tight.

I decided to let everything sit for a few minutes. Keep in mind this product does not cure, so it stays "messy". Opened back up the valve to feed air to the system and I could hear the hissing across the room. Not good after all that extra work and mess.

So that only left me with one thing to try. I took out the worst leaking part (a plug into the side of the aluminum manifold), wiped it off, wrapped it 3 times with the "better" tape, smeared a little megaloc on it, and re-insterted. The leak was completely gone! And it didn't need to be tightened ridiculously tight either.

It took a couple or 3 more hours, but I continued to rework every connection to aluminum like this (using both products) and it seems to be holding so far after an hour. I will add that the 3rd time cleaning out the threads I could definitely see some small aluminum shavings in the blocks. So maybe I just way over did it the first two times. But I think in the end the aluminum takes a little more care to get sealed perfectly.

The brass on brass connections seemed to like the additional pressure of being tightened further when they leaked. The aluminum didn't.

Well, hopefully that will be it for this project for me. I've attached a few pictures to show the products and what the setup looks like. Hope this helps anyone else down the road dealing with this.

Oh and one other note for the newbies: when you put on the teflon tape, make sure you wrap it in the direction so that it sticks when you tighten the piece. I had a few backwards and it's annoying having to redo them when you spin the connection on and the teflon tape comes unraveled.

335359

335360

335361

335362

[Greg R Bradley]

A 1/4" fitting at the tool end is not very restricting to airflow. Main pipe size is determined by total demand and distance so 3/4" is huge for one small tool and 20' but completely reasonable for one small tool and 200'.

Also, the big box store carry complete garbage for fittings. Go to a real tool store, industrial supply or order:

Foster: www.couplers.com
Milton: www.miltonindustries.com