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Improving my compressed air system, seeking advice on crazy ideas

ToadMan8

Member
I have a 4CFM, 4 gallon compressor in an outbuilding that I currently pipe in to my workshop (quieter that way). I have another 3CFM 1.2 gallon compressor sitting around.

My goals are:
  • Reduce recovery time of system
  • Add regulated drop (for rivet gun) and full-pressure drop (for other tools)
  • Maybe remove water and / or add oil to system

My thoughts to accomplish this:
  • Add second compressor to the same system, using both when working on heavy air usage jobs, and just one when doing the occasional job
  • Possibly add an air storage tank in the rafters so the system as a whole has more capacity
  • Adding a drier and / or oiler
  • Installing fixed tubing instead of using all rubber hoses like I am now

Questions for y'all:
  • Copper, galvanized steel, or black steel pipe? (PVC explodes, and flex stuff is semi-permanent, at best, I hear)
  • Will two compressors connected to one system cause problems?
  • Does the drier and / or oiler make sense?

Any thoughts would be greatly appreciated!
 
Galvanized pipe is best. Copper will work fine. Black pipe rusts over time.
Two compressors in to one large holding tank would work well.
Adding an oiler would trash the lines for future painting with an air gun.
 
You probably dont want to hear this, but you really need to upgrade to a bigger compressor ---------- while you can gang the two you have, it will never be anywhere what a single good compressor will be.
 
You probably dont want to hear this, but you really need to upgrade to a bigger compressor ---------- while you can gang the two you have, it will never be anywhere what a single good compressor will be.

Besides capacity, one of the biggest frustrations I'm having with the current set-up is that the compressor I have (http://amzn.com/B00005NMUZ) HATES to start when it's cold. I have to cycle the thermal reset a bunch of times until it's up to temp, then it works great. Do the two-stage compressors do better in sub-freezing temperatures? If so, this may compel me to upgrade more than capacity...
 
It's not the single-stage vs. two-stage attribute that makes your current compressor not like the cold. I'll bet you that it's direct drive, isn't it? A larger compressor will essentially always be belt driven. A little slip during start doesn't hurt anything.

- John
 
I have a 4CFM, 4 gallon compressor in an outbuilding that I currently pipe in to my workshop (quieter that way). I have another 3CFM 1.2 gallon compressor sitting around.

My goals are:
  • Reduce recovery time of system
  • Add regulated drop (for rivet gun) and full-pressure drop (for other tools)
  • Maybe remove water and / or add oil to system

My thoughts to accomplish this:
  • Add second compressor to the same system, using both when working on heavy air usage jobs, and just one when doing the occasional job
  • Possibly add an air storage tank in the rafters so the system as a whole has more capacity
  • Adding a drier and / or oiler
  • Installing fixed tubing instead of using all rubber hoses like I am now

Questions for y'all:
  • Copper, galvanized steel, or black steel pipe? (PVC explodes, and flex stuff is semi-permanent, at best, I hear)
  • Will two compressors connected to one system cause problems?
  • Does the drier and / or oiler make sense?

Any thoughts would be greatly appreciated!

For $500 you can have a system far superior to what you are considering and large enough for any job, including painting your plane, that you might consider:

http://www.homedepot.com/p/Husky-60...ompressor-C601H/203187350?N=c27p#.UnF3zScufd4

0af0d005-3c51-41fd-b0af-0f8a5576c47a_145.jpg


Similar units are available under different brand names at other big box and equipment stores. I have one of these compressors and it has performed admirably. Mine is plumbed with an outlet straight off the tank and another running through a regulator. The die grinder gets tank pressure and the rivet gun is regulated.

I started out with a system driven with a much smaller compressor similar to what you are describing. In spite of the extra tanks, it couldn't keep up with a spray gun.

finsh201.jpg


But the big boy is much better, wish I had it when the RV-6 project began.
 
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The comment about galvanized pipe for compressed is "always best" is not "always" correct. By designing the system with adequate condensate drains and easily maintained filters, regular black steel (ASTM A53) is preferred over galvanized for 3" NPS or smaller. Over time, the galvanic coating can flake off causing more contamination and corrosion problems than non-galvanized (black) steel piping.

Consult a piping design manual or a pipe designer before choosing your piping material.
 
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Sorry, but yes, you need a bigger compressor. It will serve you well. Tools are to be used to accomplish work, not struggled with. Larger compressor and tank will stay cooler and not spit water on your work.

Shop well, and you can find specials on a 60gal ingersoll upright around $1000 at times.

The rapid air system is nice, installs cleanly and quickly. It is only 150 psi though. If you ever get a 2 stage system it will operate at 175 psi. It is not good to step down and depend on it not failing.

I have black pipe in my system for 20 years, and keep pressure on it all the time, I mean 8760 hours per year. I had to chase every threaded joint and used permatex aviation #3 for the sealer. The leak rate is so low that it will sit 40 days without cycling if not used. It is beginning to spit rust flakes. If (when) I make another, the plan is to use hard copper and appropriate structural solder. (175 psi system). I saw a Delphi electronics factory with a copper system and it was beautiful.

Happy building.
 
Crimped fitting PEX works great for air. Cheap and easy, 100ft roll ~$35. Will not shatter if it ever breaks. Going 10 years on my shop air lines plumbed with PEX and not a single problem.
 
Crimped fitting PEX works great for air. Cheap and easy, 100ft roll ~$35. Will not shatter if it ever breaks. Going 10 years on my shop air lines plumbed with PEX and not a single problem.

It seems PEX has limits of 100 psi @180F, 143 PSI @ 73F. 125 psi would seem to be OK?

What do you run for line pressure Bob? ( just to have a baseline)

PS: copy and paste this in google for another forums discussion on all things air - "Pex-al-pex site:garagejournal.com"
 
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+1 for PEX

My shop air is 155 psi using PEX.

Works great, much cheaper than alternatives, and simple to install. It also seals up well.

I did fabricate a galvanized bulkhead fitting to pass from the garage into the shop. It's nice having the compressor far enough away that you can't hear it running.

M
 
My shop air is 155 psi using PEX.

Works great, much cheaper than alternatives, and simple to install. It also seals up well.

I did fabricate a galvanized bulkhead fitting to pass from the garage into the shop. It's nice having the compressor far enough away that you can't hear it running.

M

I'll add another vote for PEX. I've got 155 PSI running though 3/4 PEX, it's been up and running about two years, no issues to date. I initially wanted to go with iron pipe but PEX was so much less expensive and so much easier to install, I couldn't resist. I even got by with one of the cheap crimpers that you squeeze with grip pliers.
 
Increase the pipe size between the compressor and your shop, you are looking for more volume and the pipe will work as a storage tank.
Copper is the best choice if you ever need to make changes in the future.
I would also run the compressor at maximum PSI and regulate at the end of the hard pipe.
Add a tee with two ball valves one for regulator and flex hose and one pointing down for a drain.
 
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