Compressed Air Lines

[rcflyer23]

I'm thinking about adding some compressed air lines in my shop but don't have a clue where to start. I've read a few things on using PVC but see that some people don't recommend it. Just curious what everyone is using. I'd like to run a single line across one wall of my shop and have 3 or 4 connection points. Does anyone have any suggestions on this. I'd also prefer not to have to spend a ton. The biggest reason for even doing this is keeping as much air line off the floor as possible, I'm trying to run a more organized shop.

 

[bwat]

So glad you asked as I am most interested in the responses of our experienced membership as well. I hear copper is best for pro shops but a flexible option should be fine for the rest of us. Benefits for me is the added capicity of air in the lines and being able to place the compressor in an out of the way and quieter location.

 

[CDPeters]

I use 1/2" copper pipe with sweat fittings. Tees at each "drop" location with a ball valve and pneumatic quick disconnect. The ball valves will be the "big ticket" item - the ball valves can be left off since the QDs self-seal. There are many fittings available to adapt to various pipe thread sizes to mate with the compressor and QDs, although I use a short length of hose with QDs on it to connect to the compressor.

This of coarse would assume you have some skills with sweating copper pipe. Not difficult with the right tools and materials.

I would not recommend the use of PVC, IMHO it is not sufficiently rated to carry +100 lbs of air pressure.

C.

 

[TracyP]

I use 1/2" copper pipe with sweat fittings. Tees at each "drop" location with a ball valve and pneumatic quick disconnect. The ball valves will be the "big ticket" item - the ball valves can be left off since the QDs self-seal. There are many fittings available to adapt to various pipe thread sizes to mate with the compressor and QDs, although I use a short length of hose with QDs on it to connect to the compressor.

This of coarse would assume you have some skills with sweating copper pipe. Not difficult with the right tools and materials.

I would not recommend the use of PVC, IMHO it is not sufficiently rated to carry +100 lbs of air pressure.

C.

+1 On sweating copper line. Not difficult.

 

[ehpoole]

Please avoid PVC like the plague for compressed air. When it fails (and it will eventually fail from either damage or old age) it fails explosively and has been the cause of many injuries over the years. It is not that PVC can not handle the pressures we run our compressors at, but rather that, at 150 PSI, the air in those pipes will instantaneously expand 11-fold when a break occurs, literally ripping the PVC to shreds and launching very sharp shards of PVC at anyone and anything in the vicinity of the break. Since even a seemingly innocent impact, such as when moving a step ladder or board, with a PVC pipe can set the stage for catastrophic failure, it is not uncommon for the operator to be in the vicinity of the break at the moment of failure. It is worth noting that even the PVC pipe manufacturers forbid the use of their product for compressed gas (incl. air) distribution due to the high risks associated with failure.

Traditionally black iron pipe has been used for compressed air distribution due to its rigidity, thermal mass and the fact that it is typically much cheaper than copper. However, with black iron pipe you are limited to using prefabricated lengths of pipe unless you have lengths custom made and threaded for you.

I am using copper for compressed air distribution in my shop. You should stick with type L Copper (medium wall) as the thinner/cheaper type M (thin wall) is not recommended. Copper does not have the same thermal mass as the black iron pipe, but it has better thermal conductivity than black iron. Copper also has much smoother interior surfaces and does not rust and corrode internally like black iron so it maintains better and more laminar air flow versus black iron. Copper can be easily cut and sweated and readily adapted to your shop.

With any compressed air plumbing, be sure to either slope your piping back towards the compressor (for single point drainage) or towards a drain tap at the far end of the run (in which case you will need to drain at this end drain tap and at the tank). All AIR drops should draw off the top of the main (perimeter) pipe run and then make a 180deg turn for the drop. Drawing air off the top of the line helps to ensure you are drawing dry air, allowing condensed water to largely remain in the main (perimeter) line. The accumulated water in your main/perimeter line will eventually flow towards its drain point depending upon how you sloped the main line (either towards an end-run drain or back to the compressor tank). If you slope the line back towards the tank, please take care to ensure that there are no dips or loops in your flexible hose connection to the tank that would trap water in the hose. You want the water to readily drain back into the tank unimpeded, not trapped in a hose and spit back into the main line. If you choose to slope your piping towards an end-run drain, this drain tap should be located at the end of the run and drawn of the bottom of the main line (unlike air drops, which draw off the top).

If you happen to have a conduit bender, you can bend hardened type L copper pipe, though you may need to anneal it to make a full 90deg bend (due to copper having more spring-back than steel). Where greater flexibility is needed, you can easily anneal it with a torch by heating the desired section until it achieves a dull glow (or, in bright light, momentarily takes on an almost polished steel color under intense heat). This will leave the copper softer (just like copper tubing) and more easily shaped. Annealed type L copper is still plenty strong enough for the compressed air pressures we run (typically no greater than 200PSI for a home shop).

Try to avoid as many sharp 90deg bends as possible (e.g. standard copper elbows) -- either use two 45deg where possible or bend the copper (as above) to reduce turbulence at the joint. You will still need to use some elbows (and that is Ok), just try to avoid them where practical. When mounting the copper piping to your shop walls, I recommend using spacers (just make suitable blocks of wood) to hold the piping atleast 1/4" off the actual walls. This spacer will ensure that any hammering within the lines (such as from surge loads like a blower) will not result in the copper lines beating against your shop walls and making a racket.

Use a ball valve at the actual tank connection to allow for depressurizing the entire system. If there are multiple drop locations, it is good practice to install ball valve shutoffs at each drop ahead of your filters and regulators to allow emergency shutoff to a damaged hose. At each drop, install a brass elbow (e.g. shower fixture) with ears to bolt it to the wall, then attach first your coallescing filter followed by the regulator and, if wanted, an oilled lubricator or dessicant filter. The coallescing filter will trap any liquid water or oil that makes it to the drop (as opposed to condensing in the main line).

An important safety reminder when plumbing your shop for compressed air: GROUND THE COMPRESSED AIR LINES. You can purchase, from most any electrical supplier (including BORG) pipe clamps with ground connector that you can attach to a convenient point along your piping, then ground with atleast #12 (#10 even better) copper. This will provide critical protection should your compressed air distribution lines ever become energized due to a wiring fault in your shop -- it will also dissipate any static accumulation.

Miscellaneous Tips
Another tip: If you wish the option placing drops anywhere you wish in your shop, consider running a continuous loop all the way around your shop perimeter (don't forget the slope the lines back towards the tank!). If you feed both ends of this line then you will also gain pressure balancing properties throughout the system AND you can opt for one pipe size smaller for the main line if you wish to save money because each drop will be provided air from both sides of the main line.

If you are only running a single drop then 1/2" copper is a good starting point. If you are going to do multiple drops then consider 3/4" copper for the main distribution line (you could do 1/2" if you do a full perimeter -- like the above -- and feed from both ends). If you need to provide more than 20CFM (sustained or surge), then run either a 3/4" perimeter system fed from both ends, or upgrade to 1" pipe if making multiple drops. In a shop setup, you risk losing more than you gain if you opt for anything less than 1/2" type L copper pipe.

FWIW, in my shop I am running about 60ft of 1/2" Type L copper pipe since I will only be feeding a single remote drop and my current setup is meant to be temporary (we're discussing building a new shop in a few years). If I were doing multiple drops or a longer run, I would have gone with 3/4" for the main line. In the future, if we build a new shop, I will install a 3/4" perimeter main line (fed at each end) with 1/2" lines for the actual drops.

I wish you the best of luck with your install. Let us know if you have any other questions -- including how to sweat copper fittings.

 

[CDPeters]

You should stick with type L Copper (medium wall) as the thinner/cheaper type M (thin wall) is not recommended.

Ethan -

Any reason other than durability to use Type L over Type M? Type M is rated at 850 psi, which I should think would be quite sufficient. I do recognize that the Type L would stand up better to dings and dents, but the cost factor is nearly double.

Thanks as always for your clear, concise and complete info! :icon_thum

C.

 

[KenOfCary]

Any thoughts on the merits / demerits of this system.

http://www.rockler.com/product.cfm?page=30321&filter=rapidair

Seems easy to install and is rated at 150 PSI.

- Ken.

 

[wooduser]

In the interest of economy and flexibility, I purchased a hundred foot length of air hose and used that for distribution. There are brackets available at Lowes for this also, very cheaply (I mean economical) that can be used on the ceiling walls, etc. You can then use copper for the last foot to attach regulators, quick disconnects, etc.
I go along with the use of PVC. It is a ticking time bomb that will blow up.

 

[rcflyer23]

Ethan,

Thanks for the education. I greatly appreciate that. I will look into all of this and price out some copper. I think I may only run one maybe two connections especially sine the wall I will put it on is only 20 ft. I am interested in what you think of the rapid air system as well. I found it earlier today and looks very well put together but I don't know how it compares to a copper system I price or potential durability.

Thanks again that was very informative.

 

[Bill Clemmons]

Kevin, I took a slightly different approach. Inside the shop, I have 3/4" black iron pipe running around the perimeter at ceiling height. Every so often, I used a 'T' to drop a 1/2" pipe down the wall. At the bottom of that drop I installed a ball valve to drain moisture from the lines. Just above the ball valve, I have another 'T' w/ a pressure guage and a quick disconnect for my flexible hose to attach. I didn't price copper, so I'm not sure how this compares cost-wise.

Instead of running the flexible hoses across the floor to get where I need them (usually in the middle of the shop) I installed bicycle hooks in the ceiling and loop the hose from them, w/ a drop down where I need them.

My compressor is outside, and the connection from the compressor to the black iron pipe is a heavy duty flex hose, to absorb the vibration.

HTH

Bill

 

[Woodman2k]

Kevin,
That rapidair is one of many nylon type airlines,Synflex is another. We use the synflex brand at work on compressors up to 220 psi and other than using compression fittings on the 220 psi models the push in fittings work real well as long as you have good square cuts at assembly and you take it apart correctly if you need to disassemble it.It comes in 3/8 and 1/2" and also in metric equivalents.I have it in my shop and have never had a problem in 17+ years. You can get fittings that will allow you to adapt to any setup.Mc Master Carr and most industrial supply houses carry one brand or another.Let me know if you have any other questions.
Greg

 

[junquecol]

NEVER under any circumstances slope air line back toward air compressor! If you do, after each air use any moisture starts back towards compressor, to only be brought back upon next air use. Slope then AWAY from compressor. Each air use pushes it towards drain. Drain at far end (lowest point.) Take offs need to be from TOP of piping. If they are from bottom, then moisture will follow, as it will be on bottom of pipe (water is heavier than air.) For sweating pipes, go by a true plumbing supply house and get LACO brand flux. (Read the post about LACO in Home Improvement forum.) Unless pipe is awful dirty, you don't even need to clean it prior to fluxing. PVC is not rated for compressed gas (says so right on every piece), and air is a gas.

 

[ehpoole]

Ok, my opinion on some of the questions asked since my post...

Firstly, please visit this Air Piping Layout for a diagram of a recommended compressed air plumbing strategy.

Why Type L (medium wall) versus Type M (thin wall) Copper?
The effective pressure rating for Type M copper will actually be approximately 400PSI rather than the 800PSI as Chis was inquiring. In the course of soldering -- especially for a beginner -- you are very likely to be annealing the copper line at the solder joints (particularly if using a MAPP gas torch vs. propane). Additionally, the line needs to be further derated because, during extremely heavy use, the air temperature towards the tank side of the line can reach 200-250F on air compressors without integral aftercoolers or refrigerated dryers. (NOTE: manufacturer recommended working pressures are further derated depending upon the type of solder used -- as little as 100PSI for certain types of Tin-Lead solder).

While Type M, even at 400PSI, is certainly greater than the 150-200PSI our compressors are likely to produce, I generally like to work with a 300% rating on pressurized systems. Additionally, I don't know if you have ever worked with Type M copper, but it is remarkably easily crushed and damaged compared to Type L. The thinner walls will also be subjected to a greater degree of expansion and contraction due to pressure fluctuations over the life of your install which will place greater stress on your solder joints -- so there is a greater risk of developing leaks at the various fittings with Type M (thin wall) copper versus Type L (medium wall).

Even with this strong preference for Type L, if I were choosing between PVC and Type M, I would choose Type M -- atleast you are not risking life and limb, so to speak, with the thin wall copper the way one would be with PVC.

Opinion on RapidAir (and the like)
I have nothing negative to say with regard to safety of the RapidAir setup. It is basically a reinforced flexible tubing system, so it does not have the same safety concerns as with rigid PVC piping. I do wish, however, that RapidAir had a greater working pressure rating as many air compressors are capable of exceeding the manufacturer's rated working pressure unless the compressor's pressure switch is adjusted to deliver a lower pressure. At least if their system fails you won't have the same dangers as associated with PVC -- just a compressor that's potentially left running 24x7 until the break is discovered (not a huge deal with 100% duty compressors, but a concern with compressors not rated at 100% duty cycle).

However, the RapidAir tubing is typically used in professional installations which typically include a refrigerated dryer and, as such, deliver already dry air to the user. Our typical shop setups do not tend to include refrigerated dryers, as such our systems provide much wetter air. Part of the function of a copper or iron piping system (the longer the better) is to provide the hot incoming air time to cool down and transfer its heat to the metal piping. This causes excess moisture to condense in the metal pipes and, provided we draw our air of the top of those metal pipes, allows for the delivery of considerably drier air than we would have obtained straight from the air compressor's tank. It still will not be as dry as air provided by a refrigerated dryer, but it is much better than what you would obtain without the cooling provided by the metal piping.

The issue I have with respect to RapidAir (and comparable setups) is quite simple. The RapidAir piping has a much greater insulation value and far poorer thermal conductivity than that of either copper or iron piping. You will still benefit from some cooling within long runs with RapidAir piping, but nowhere near the same extent as with metal piping. It is also much more challenging to ensure a consistent slope with the more flexible RapidAir piping than with copper or iron piping. Everywhere there is a dip in the RapidAir piping there is an opportunity for condensed water to accumulate. The only thing worse than an air tool spitting a little water is an air tool spitting LOTS of water -- remember RapidAir is usually installed in professional setups that include a refrigerated drier which means NO water condensing in the lines, so this is a matter of some concern to me.

Use of Mounted Air Hose for Distribution
See RapidAir comments above, they are largely similar concerns

Comments on Black Iron Pipe - a Possibly Cheaper Solution
If concerned about the price of copper (it is not cheap these days), black iron piping is a traditional distribution system and is often cheaper than copper. Due to the rougher interior, use a minimum of 3/4" black iron for the main distribution line to reduce the losses in pressure and air speed. You will have to invest more time in a black iron pipe system since there are many fittings that must be well sealed with either Teflon tape (use yellow Gas tape) or suitable pipe dope.

Install periodic unions throughout your black iron pipe setup so that if you are plagued with an unwanted air leak down the road you will not have to disassemble your entire distribution system just to tighten the troublesome connection. Without unions the act of tightening one pipe connection invariable loosens the next connection -- with unions you just need to retighten all the joints within the affected section to correct the leak. Fixing a leak can still be a lot of work, but I would rather retighten or re-do 1/4 or 1/3 of my distribution system (up to the unions) than 100% of it!

Keep in mind, air leaks much more easily than water, so Teflon tape and/or pipe dope will be your best friend in this application. You can get by with traditional white Teflon tape, but you will need at least 3 times as many turns of the white Teflon tape versus the yellow Teflon tape to achieve the same result

Comments on Galvanized Piping
Although it looks nicer than black iron piping, many suggest avoiding Galvanized steel pipe due to zinc flaking off and plugging the air filters in coallescing filters. Personally, I'm not sure that this is really any worse than rust flakes from black iron pipe. Either way, don't ever use a blower to clean up unless that blower is drawing air through a coallescing filter with either an integral fine paper or sintered brass air filter -- you do not want flakes of zinc or rust embedded under your skin!

Closing Comments
These are my opinions and are based upon extensive research I did when planning my setup. Ultimately, you will need to install whatever setup works for your shop and within your available budget. The only *really* strong opinion I have is the avoidance of PVC distribution systems as they are just too unsafe. Woodworking can be a dangerous enough hobby with all our sharp hand and power tools without introducing homemade overhead IEDs into our shops!

HTH

 

[ehpoole]

NEVER under any circumstances slope air line back toward air compressor! If you do, after each air use any moisture starts back towards compressor, to only be brought back upon next air use. Slope then AWAY from compressor.

While end-run drains are more optimal, that is ONLY true if they are regularly drained. Considering many barely remember to drain their tanks, I would prefer such users drain back to their tank than trap gallons of water at the end of their run. That said, none of my comments discourage users from employing an end-run drain if they are sufficiently dedicated to draining them daily (or several times a day under heavy use). YMMV

Under anything approximating normal use, the user will not draw air CONTINUOSLY nor will they typically draw so much air that the water can not flow towards its drain point (either tank or end-run). On the rare case that the average user draws enough sustained air to overwhelm gravity's hold on the water it will be trapped by the coallescing filter. Even so, simply adding a couple feet of horizontal pipe at the end of the main line (in a tank-drain setup) -- your final air drop should never draw from the very end of the main run -- will provide a parking location for any excess water until it can drain back towards the tank. The vertical elevation of each drop, drawn off the top of the main line, will further reduce condensation's access to the point-of-use outlet. I aim for a 1" drop towards the drain (either end) for every 5-6ft of pipe, enough to give gravity a good hold -- though, you can get by with less drop for end-run drains.

Keep in mind that these are typical one-person shop applications. This is not an industrial application where large volumes of air are continuously moving and pushing against any condensate. As such, in a one-man application the water will have many opportunities, and plenty of time, to work its way back to the tank under anything approximating typical usage (including spray finishing your latest masterpiece). If a user finds that they actually run into any drainage issues, the simple addition of a drain leg to their drop line will remedy the condition and is a simple retrofit.

 

[KenOfCary]

Ethan,

You do seem to be very knowledgeable on this subject and I appreciate your sharing this knowledge. Assuming I'm committed to the RapidAir system since I've already purchased the distribution kit, I have a few questions about optimal installation.

The way the kit is designed it doesn't lend itself to a single run with taps. It has a manifold that has two 3/8" taps and a drain connection in addition to the in-flow connection. Then each air outlet is a 3 hole affair. It is an aluminum block milled with 3/8" taps. In my installation the in-flow would be at the top of the block and there is a 45 degree brass fitting that goes from the 3/8" side tap to a 1/4" Quick Disconnect coupling. The bottom tap then has a ball valve fitting meant to be used as a drain. The air outlets would be mounted to a rafter in the ceiling above my assembly table and other areas where air is needed.

This is what the air outlet looks like.

http://www.rockler.com/product.cfm?page=30444&filter=Rapidair

My question is you mention a coalescing filter. Where in the system would this be? If I understand them correctly they need to be installed vertically with the hose connections horizontal. This doesn't seem to be an ideal configuration in my application if this should be at the end-point. Or is the filter at the source-point in front of the manifold.

- Ken.

 

[ehpoole]

Ken,

If I understand correctly, this is the RapidAir kit you purchased with 2 outlets, distribution block and 100ft of hose?

If you can possibly do so, try to get at least 20+ft of copper/iron pipe between the tank and the distribution block. This will allow much of the water to condense from the warm air while also protecting the RapidAir tubing from the high temperature air (and oil) that a compressor can generate after it has been running for awhile. This will be more effective than running the RapidAir piping direct to the compressor -- even if you have to make zig-zags with the copper/iron to get to the 20ft mark. (Note: If you go the zig-zag route, keep drainage of the assembly in mind -- don't trap the water in a maze.)

With regard to your question as to where to locate the coallescing filter... Skip the 45deg fitting and purchase a combination coallescing filter plus pressure regulator. A combo unit will provide the two functions in a more compact package then seperate coallescing filter and pressure regulator components would otherwise allow. You could still use invidual components, but as two units they (combined with the quick connect) can protrude up to a foot out from the wall. A combined unit will cut 4-5in off that protrusion.

You can then either mount the quick connect direct to the pressure regulator or install the 45deg fitting and then the quick connect. Or you could do like I seem to like doing, and install a 3-way tree fitting, allowing for up to 3 quick connect fittings at a single outlet (e.g two Universals/Type-M and a Type-T).

Be sure to adequately secure the RapidAir tubing so that pressure differentials can not cause it to 'thump' within your walls. Clamping the tubing will also restrain it if a an end ever comes lose -- you don't want to get spanked by your own compressed air line! I have read some interesting stories about what a damaged air hose can do to a parked car over a lunch break!

Because the RapidAir system has a maximum working pressure rating of 150PSI, you may need to dial down your air compressor's cut-off pressure (and possibly adjust the cut-in pressure as well) -- say 120PSI cut-in, 145PSI cut-off. Most pressure switches will have 2 or 3 adjustment screws for setting these two parameters (on 3-screw setups, one screw will be coarse adjustment, the other fine adjustment). Be careful some of the screws under the pressure regulator's cover are HOT, so use an insulated screwdriver in case you accidentally contact one of them!

I don't know if this is obvious or not, so heregoes: The RapidAir lines will ideally run at your full unregulated tank pressure. It is best to distribute high-pressure air to the outlets and then install a regulator at each outlet -- especially since you already need a coallescing filter at each outlet. This provides the best possible/practical pressure regulation by reducing the unwanted effects of line losses. It is possible to get by with a single central regulator installed at the tank, but your line losses will be more unpredictable since the amount of loss will depend upon a given application's air consumption. Without installing a gauge inline with the remote tool, you will have to guess the proper regulator setting. For nailers this isn't terribly difficult -- set the regulator for 100PSI -- the normal air reserve in the lines themselves will handle the brief surge of a nailer. But, for higher demand tools, you would need a gauge installed near the tool to know what regulated pressure at the tank outlet corresponds to a given operating pressure at the remote tool. This is why I encourage installing a regulator at each outlet and running the distribution line at full tank pressure -- it takes a lot of the guesswork out of the equation! Seperate regulators at each outlet also allows you to set a custom pressure at each outlet matched to the tool in use at that outlet (e.g. HVLP outlet at 40PSI; nailers at 90-100PSI).

In use, you will want to drain all the drain legs pretty religiously. Unused taps should not have much condensate, but you should expect condensate at the distribution block's drain (esp if you install metal piping ahead of it) as well as the drains at whatever taps you have used for the day (and don't forget the tank drain). It will help to concentrate condensate at the distribution tap's drain if your remote outlet piping draws off the top-side and has some vertical elevation as it leaves the distribution block -- this way the drain leg is well below the level of the outgoing remote air lines.

I'm not an expert on all of this, but I did spend many hours studying all the related topics and discussions for my own setup. These are my opinions on the topic based upon what I have learned tempered with my experiences along the way. Hopefully this information will prove helpful to others as well.

If you have any other questions, feel free to ask.

 

[ehpoole]

Ken,

I missed your comment about your wanting to install your outlets in your shop ceiling....

That is really a much less than optimal configuration since it would place the pressure regulator and coalescing filter in an especially awkard location (and likely equally awkward orientation).

There are three choices in order of descending preference (or at least My preference):

1. Install the RapidAir outlet in a wall location, then run the coallesced (filtered) and regulated air to a ceiling receptacle with as short a line as practical. (So as to try and limit line losses to those of the actual hose). Alternatively, install a 3/8" by 25-50ft retractable hose reel on the ceiling and then run a short hose from the ceiling mounted reel to the wall mounted regulator plus coallescing filter assembly (which itself is screwed into the RapidAir outlet block).
2. Install a totally different type of coallescing filter -- an inline coallescing filter -- and a mini regulator at the hose end (literally either on the end of the tool or connected between a 2ft leader hose and the drop hose. This allows for the best possible regulation (though slightly less optimal arrangement for the coallescing filter). However, the disadvantage is that the regulator and filter will add weight to the tool and could ding your project if they get swung into your project.
3. Opt for the central regulator (at the tank) option that I mention in my prior post but encouraged you not to do. You will need to install an inline mini-pressure gauge at your tool so that you can properly set the operating pressure for the tool since line losses vary considerable depending upon both operating pressure and the volume of air consumption. For nailers it is not so critical -- just set the central regulator to 100PSI -- the air stored within the hose itself will accomodate the brief surges of air demanded by nailers. However, for continuous use tools (either low or high volume) you will need that pressure gauge mounted just ahead of the tool to know how to set the central regulator.
   
   The problem, if you wish, is that the the central (tank-side) regulator will show you the outlet (line) pressure AT THE REGULATOR end of the equation. By the time you account for all the losses along the length of the hose and various fittings, the ACTUAL PRESSURE at the tool may be much less than what you set the central regulator to. This is why you need a mini-gauge on the tool itself -- you will pull the trigger on the tool to simulate use and THEN dial the central pressure regulator up or down until the TOOL's GAUGE reads the necessary target pressure.
   
   Further, realize that the only place you will be able to install your coallescing filter at will be the distribution block inlet -- which makes that 20+ft of copper/iron piping all the more critical. This means that you will likely end up with condensed water issues from time to time with respect to whatever tool happens to be running. Although the outlet blocks have a drain leg, the drain leg will vary between considerably less effective and utterly ineffective as well when mounted in a horizontal (ceiling) orientation. The RapidAir outlets are actually designed for vertical, flush, in-wall installations -- I'm not sure if they manufacture a special ceiling receptacle which would be of a very different design. If your ceilings are unfinished (open rafters) you can improve the drainage element considerably by mounting the RapidAir outlet vertically on the joist (as if on a wall).
   
   This is likely better than having a heavy mini-regulator and inline coallescing filter banging into your project, but it means having to return to the compressor to adjust and customize the system pressure for each tool in use. And because there is only the one central regulator, any change alters all the RapidAir outlets so you can not have different outlets dialed into different pressures. This is my least favorite solution, but it is also probably the most practical for you if you can not accept solution #1 (above).

I really encourage you to go with a variation of option #1. It avoids the heavy inline filter and regulator assemblies of option #2 and the regulation and condensate drainage problems inherent in option #3.

Sorry for any confusion the oversight may have created... somehow I missed the ceiling receptacle portion of your question! If this post seems to ramble a bit it is because it is getting late and I nearly forgot to account for the condensate issues a ceiling mounted receptacle introduces with the RapidAir design versus typical in-wall installations (esp. in option #3).

 

[Glennbear]

JMTCW..........Being a traditionalist I used black iron pipe to plumb the air in my shop. I got around the cost of pre-made pipe nipples being expensive by purchasing longer lengths of pipe and threading the sizes I needed myself. A hand pipe threader from HF was not a bank breaker and allows me to thread 3 different size pipes so it is also handy for making up lengths for pipe clamps. The ability to thread 1" diameter pipe has also been helpful for various shop projects such as supports and legs. :wsmile:

 

[KenOfCary]

Thanks Ethan, that's a lot to digest. That is indeed the kit I purchased along with an additional manifold and additional outlets.

To clarify a few points. My compressor is a CH WL67500 which is oilless and mounts on the wall. I have one auxiliary tank making it a 16 gallon system. My ceiling is unfinished and the rafters are an engineered rafter which has an open design so will be easy to make vertical or horizontal runs of pipe inside the rafters. I was planning on hanging the overhead outlet to the rafter similar to it being mounted on the wall. There would really only be one overhead drop above my assembly table which is in the middle of the shop behind the table saw (it doubles as an outfeed table.) The primary use here would be finish nailers.

The other outlets would probably be along a wall and primarily used for a handheld air gun to blow dust off of things and the occasional need to use a nailer in another part of the shop. The shop is only about 22x24 (it used to be a two car garage before I removed the garage doors and completely insulated the area.)

The compressor is in the front corner of the shop. I'll have to think about how I could get a 10 foot run of copper without running into an obstruction. (maybe in the rafters.) And I'm also trying to figure out what connectors would adapt from the pipe to the typical NPT fittings on the air hose.

I don't currently have any HVLP equipment and would probably not be using it in the shop if I did due to ventilation issues. (it is a walk-out basement with a single window in front and there is a gas water heater in the back corner, so have to be real careful with volatiles.)

Here's a picture of the compressor in the front corner of the shop.

http://www.ncwoodworker.net/pp/showphoto.php?photo=56547&ppuser=5363


- Ken.

 

[Woodman2k]

I think with the fact that most any consumer products that have a pressure rating have been tested at far higher values than they rate them for.We at IR test to a minimum of 380 psi and on our 220psi units test to almost 600 psi. Considering the pressure drop coming across your various fittings,filter,and regulator and there will be a pressure drop the 150 rating is nothing to be concerned about.I worry more about the fact that made in China is on alot of this stuff and they have no conscience whatsoever.
Greg