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Observations and Lessons learned installing compressed air system.

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Forum topic by Whiskers posted 125 days ago 1112 views 1 time favorited 36 replies Add to Favorites Watch
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Whiskers

389 posts in 624 days


125 days ago

Anyone familiar with my postings knows I’m setting up shop, and one of the things I have been working on heavily the last couple days was a good compressed air setup. I did lots of research in various forums, many of them garage etc and the universal consensus was the best materials for this is metal pipe. If your into painting cars, galvanized pipe may be best, otherwise ordinary black cast iron pipe is fine. The reason for the difference is that the black pipe is more conducive to rust, and rust to a car painter is like silicon is to woodworkers.

My design started simple, I wanted air available everywhere while keeping my compressor conveniently stowed away. In one corner of my garage I’m building a equipment closet that stows my compressor, dust collection setup, water heater, and has storage for lots of other stuff or future equipment. My super fancy HF $110 compressor will sit on a shelf over my hot water heater. Air outlet consisted of a HF reel which hangs from the ceiling and has 50’ of rubber hose. If you ever been in a professional garage you have probably seen similar things. All I needed to do was connect them. A light switch on the outside of the closet would turn on/off the power to a ordinary wall outlet to power the compressor on and off without having to run in and out of the closet. It got expanded a bit cause upstairs over the garage is my master bedroom, and I wanted a air outlet there near my desk cause I also like to make models, especially in winter when it cold, and do airbrush work. Since I don’t want to run up and down the stairs when I am playing I am putting in a 2 way switch with one upstairs and one on the outside of the closet.

Rule 1 which is universally accepted among most anyone is avoid any and all plastic type materials. It will invariably fail over time. Some people use these fancy expensive plex and other weird plastics but they are expensive, will eventually degrade and fail, catastrophically sometimes, and are usually very small in diameter restricting airflow. I’m not sure how significant it is, but if you got runs of 1/2” metal pipe it going to act just like the tank on your compressor expanding the stored air. Maybe one of you know it all mathematicians will pipe in and tell me how many gallons of air my 30’ or so of 1/2” diameter pipe has added to my total storage.

One problem with working with metal pipe of any kind is you have to pick one end and run to the other. If you ever have to break a piece apart you practically have to tear the entire line out. A thing called a union helps solve this problem as it can be tightened on both sides, but be prepared to work from end to end and get it right the first time as you go.

Rule two is be prepared to pressurize and test every couple pieces of pipe. Metal pipe is a pain in the ass to get a air tight seal. Now here is where some of my new found experience has come in. In the past I’ve always used teflon tape to seal air connections. It seemed to work better than pipe joint compounds and was much more convenient cause usually it seemed when I needed it the pipe joint compound would be dried up and useless. Well here the thing, for brass or chromed steel fittings the teflon tape is fantastic, the best material. It works, cleans out easily if you change fittings, and is always ready to go. But it sucks to seal pipe, it won’t work. The threads are too big and sharp. I’m just telling you this up front so you won’t waste your time with it. Small brass or chromed steel fitting, go with the tape, Pipe, you will have to use the pipe joint compound, and even than, test test test, cause metal pipe a pain.

Rule three, don’t be a gorilla, you do have to tighten things up good, but it doesn’t take a terrible amount of pressure. Besides, cast iron is a soft material, easily stripped.

Rule Four, when drilling holes thru wood for the pipe to run through, and you should, make pieces to support it etc, running thru floors especially this applies, go a little oversize. Don’t drill a hole just the perfect size for the pipe to slip thru. It a pain in the ass when dealing with large holes to widen them later, and with pipe it needs a little wiggle room to get it in position properly. A half degree off you can’t get the fittings and pipe to align. Go back later with some silicon caulk after the pipes are in to seal them into their holes to shut off bug or air traffic flows if that what your concerned about. If your working with 1/2 pipe it is 7/8” outer dimension. When Drilling thru a wall or floor, go a full inch when drilling the hole, you will be glad you did. For support pieces that you may make 15/16” is purrfect.

A few more notes, not rules. This stuff is nasty to work with, be prepared to become really dirty. Find some clothes you have written off and are ready to throw out and just wear them from start to finish on the job, and than toss them.

Black pipe can be painted, Surprise! :) but prepare first before putting it up. Great way to deal with any pipe, black or galvanized, is get a gallon of WD40 from tractor supply or somewhere for about $20. Wet paper towels or a sponge heavily with it and clean the exterior of the pipe. Galvanized pipe has a oil coating on it to help release it from the mold, and that oil is kind of hard to clean, Black pipe has something even more terrible and insidious, and really a pain to clean but the WD40 does a great job of removing it. After that you than have clean the WD40 off, which is still a oil, but a much easier to clean oil. Simple Green works great for this. Let it cook in the sun a bit to dry and prime, paint, enjoy.

If there is any interest in this thread I’ll come back later and post pictures to show methods of how to run the pipes them self, Especially for water drainage which is super important and how I did some of the supports etc. It late now though and I just got all that nasty black pipe gunk off me and not going back into the garage.

One more final piece of advice, when sourceing your materials, find a nice local ma and pa type hardware store for all the small stuff. Fittings, Nipples (short little pieces of pipe), etc. Buy extras and lots of them, you always seem to be off in measurements, have to make little jogs around unexpected obstacles, etc, and it better to have lots of stuff to work with when doing the project rather than waste time running back and forth to the store. With the small stores returns are easy. For the pipe itself, go with Lowe’s of HD, they are as cheap as anyone and will cut and thread it for you. Also it cheapest to buy a 10’ hunk and have it cut and threaded rather than buy the pieces they already cut for you. I don’t know why that is, it just is. They may say they can’t cut and thread less than 3’, but that not true, they can go down to a foot. Just need to find a smart boy who knows the machine.


36 replies so far

View Monte Pittman's profile

Monte Pittman

13228 posts in 935 days


#1 posted 125 days ago

Good you’re making progress. I would suggest that you have a filter on the air intake of compressor if it is with the DC. Dust is a compressor killer.

-- Mother Nature created it, I just assemble it. - It's not ability that we often lack, but the patience to use our ability

View Whiskers's profile

Whiskers

389 posts in 624 days


#2 posted 125 days ago

hmm, something I hadn’t considered. I have never seen the DC spitting dust, guess when it all together I can observe it for a bit. The compressor has a little filter, but it is weak. I’ll keep the concept in mind, but I’ve never seen dust coming out of the dust collector. LOl, easy detection, run dust collector, walk in closet, if i sneeze there might be a problem.

View MalcolmLaurel's profile

MalcolmLaurel

210 posts in 220 days


#3 posted 125 days ago

Actually plastic piping is fine for compressed air, as long as you use suitable tubing that’s rated for the pressure you’re using. PVC water pipe is not suitable as it’s brittle and can’t take repeated pressure cycles. I used 1/2” polyethylene tubing ($0.32/ft from McMaster) which is rated 150 psi, with matching plastic compression fittings. Cheaper and a lot easier to work with than black pipe! I used galvanized pipe nipples at the quick disconnects, which I mounted to the ceiling at various points.

-- Malcolm Laurel - http://MalcolmLaurel.com https://www.etsy.com/shop/MalcolmLaurel

View crank49's profile

crank49

3337 posts in 1568 days


#4 posted 125 days ago

Copper pipe is a great airline material. It is used in many industries.
PVC will explode eventually.
PE if designed for air service is good and it’s easy to install as Malcolm said.
I worry about plastics due to UV degradation, but some are specifically designed for the purpose and should be okay.
To the OP, I have used Teflon tape on black and galvanized pipe fittings for 40 years for air, gas, some hydraulic and all water piping and never had a problem as long as the fittings were well made. Today it’s hard to find quality fittings as most of them are cheap ass imports from India or China, especially in the box stores. Maybe your fittings are the problem.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View Jim Finn's profile

Jim Finn

1638 posts in 1519 days


#5 posted 125 days ago

I put my air compressor in a separate building and put my dust collector outside in a, built for it, enclosure. No dust in my compressor and I cannot even hear the compressor from inside my shop.

-- In God We Trust

View Grandpa's profile

Grandpa

3044 posts in 1273 days


#6 posted 125 days ago

Teflon tape lubricates threads so you can actually tighten the joint more. Since pipe threads are tapered this can be important. I use a pipe thread dope that has Teflon in it. I like it although it can be messy. I haven’t experienced this problem with Teflon tape though. It is specifically designed for gasses such as air and not actually designed for water. One thing you need to remember is to not go over the end of the threads because you will get small pieces of the tape in your tools. I also believe the galvanized pipe will have small particles of galvanize come loose and get into your tools or finishes. Use black pipe with water drains and a good filter at the business end. water and oil can be separated from your air.

View Shawn Masterson's profile

Shawn Masterson

1240 posts in 546 days


#7 posted 124 days ago

I used pex with metal fittings (rated at 140 psi) in my shop 4 years ago, and have had no problems. It has been in my stepdads body shop for 15 years and never missed a beat. I feel you are being very judgemental and dismissive of pex. It is a thousand times easier to run. It pulls through walls just like wire. also it doesn’t hold cold like steel pipe, so there will be less condensation and no rust ever.

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Grandpa

3044 posts in 1273 days


#8 posted 124 days ago

My friend owns a machine shop. He installed PEX for his compressed air. When he changed buildings 4 years later he took the PEX down and moved it with him. So far he has had no problems with bursting or shattering.

View MalcolmLaurel's profile

MalcolmLaurel

210 posts in 220 days


#9 posted 124 days ago

Michael, yes, copper is also a good option… easier than iron but more expensive these days. Where I work, all the air lines are copper, up to 3” (it’s a good sized plant).

-- Malcolm Laurel - http://MalcolmLaurel.com https://www.etsy.com/shop/MalcolmLaurel

View Whiskers's profile

Whiskers

389 posts in 624 days


#10 posted 124 days ago

Thought I would get back to all the posts you guys made and make some replies and ask some questions.

For those talking about Pex, I’ve heard about it, and many people use it happily, but the Pex I’ve seen is very small in diameter and expensive. In retrospect, I would have done my little run to the upstairs in Pex if I had thought about it, cause air brushes don’t eat the air that tools do. It sure would have been easier. I even have a 2nd air regulator that will be mounted to the wall that cuts the pressure down to 20-40 lbs for the air brush. I should mention that I have some automotive air tools that eat more air than woodworkers typically need.

Crank, can you buy anything that not made in China? Yeah China was printed on all the fittings I have seen, from anywhere.

Jim, my little closet is expensive enough, can’t afford to build a outside enclosure and run power to it.

Grandpa, I’m not sure the machine at Lowe’s tapers the threads.

Copper, yes it is great material, but super expensive. Most of the posts I seen from folks who used that specifically were into auto painting, and didn’t want any rust, or managed to scarf it up from some salvage operations they pulled off. Also, doesn’t copper have to be Braised with a torch? There is no way I could have safely attempted to learn braising with a torch in the spaces I ran my pipe, My house would now be a pile of ash. I can’t see how learning to braise and maneuvering a propane torch in confined spaces is easier than operating a pipe wrench.

View hydro's profile

hydro

208 posts in 349 days


#11 posted 124 days ago

Iron pipe of any kind, black or galvanized is the worst possible option for a properly designed compressed air system. I exclude PVC here because it is just dangerous, foolish, and effectively illegal per OSHA regulation. The problem with Iron is that the water and acidic oil residue from the compressor corrodes it from day one and galvanized is particularly insidious because the zinc will come off in flakes as the inside of the pipe corrodes. Also, the threading process is difficult to do in the first place, is prone to leakage, and very difficult to change. Copper is just too expensive to consider commercially these days.

The industrial standard (Where keeping pipe fitters busy threading pipe is not a priority) has shifted to thin wall aluminum pipe systems. Corrosion is not a factor, few tools are required to assemble airtight joints, it is easy to change, and the cost is only slightly higher than iron pipe once you consider the time spent assembling the system. Do some research and see what the advantages are.

-- Minnesota Woodworkers Guild, Past President, Lifetime member.

View Whiskers's profile

Whiskers

389 posts in 624 days


#12 posted 124 days ago

LOL, thanks for the amusing post hydro, it almost reads as a PR piece, but the concept is ludicrous. Industry standard my ass. How can a product that don’t exist be a standard. I have never ever seen a piece of aluminum pipe in any store. I have also never heard of anyone using aluminum in a compressed air system in any forum. Aluminum is also very expensive, maybe even more so than copper. It also soft and not as tough as other metals. Since aluminum pipe does not exist in a commercially viable form, it not relevant to speak of.

View DIYaholic's profile

DIYaholic

12885 posts in 1272 days


#13 posted 124 days ago

Aluminum compressed air tubing….
http://www.rapidairproducts.com/fastpipe.asp

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procratination a bad thing?

View Whiskers's profile

Whiskers

389 posts in 624 days


#14 posted 124 days ago

LOL, mail order 10’ pipe? are you kidding?

View DIYaholic's profile

DIYaholic

12885 posts in 1272 days


#15 posted 124 days ago

FREE delivery available to store….
http://www.northerntool.com/shop/tools/product_200582745_200582745

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procratination a bad thing?

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