Air Compressor Setup

[Larry Nall]

Well the tax man has come and gone and I still have some skin left, sooo...it's time to buy a tool.

My trusty 10 year old Air Charge (aka Devilbis) 4hp, 12 gal portable has given up the ghost. I'm not sure exactly what happened with it but it might have had something to do with excessive acceleration on an on-ramp with the tailgate in the down position.

I bought a small nailing compressor which has gotten me by (Hitachi - which is a nice machine BTW, but that's another subject). Anyhow, it's time to bring in a stationary machine.

I've pretty much settled on the IR, 60gal, 3hp unit ($629 @ Tractor Supply)that's so popular with a lot of folks here at the Creek. This is unless sticker shock gets to me at the last minute and I go for the CH @ Lowes ($400). If ayone can convince me that I'll be as happy with the CH as the IR, you'll save me a bunch of money.

So, my thoughts and questions are:

1) Mounting - There seems to be two schools of thought here. Most bollt into the floor with vibration isolators or hockey pucks between the machine and the floor. The other school just leaves it bolted to the shipping pallet. I'm leaning towards the latter mostly due to laziness. Any thoughts pro or con on this?

2) Plumbing - I've got a design in mind using 1/2" black pipe. The compressor is at one end of the system and the painting station is at the other. In order to keep moisture out of the tools and especially the paint, I was thinging of putting a filter at each end. Given that I spray mostly water based and shellac is that even a big deal. Also the CH2121 filter (~$27) is about the only thing carried locally. Is that going to work or should I order something more substantial?

3) Pipe connections - Some where in my research I read that teflon tape isn't up to the pressure of an air system and recommended pipe dope for a leak proof system. Has anyone had a bad experience with the tape?

Any other advice you care to render will be appreciated. I'll probably start buying and building next week.

Thanks a bunch
Larry

[Rich Engelhardt]

If ayone can convince me that I'll be as happy with the CH as the IR, you'll save me a bunch of money

When you stop in Tractor Supply, check out the life expectancy of both.

I believe the IR is rated for 8000 hours @ 100% duty cycle, where the CH is rated for 5000 hours @ 50% duty cycle.

The CH is a good compressor that will serve you for a long time.
The IR is a great compressor that should last the rest of your life - given reasonable care.

BTW - keep a sharp eye out for a sale on the IR.
They frequently go for @ least $100 off the regular price - sometimes more.
I want to say that 3HP 60 gal tank was around $499 last year when I bought my 4 gal twin hot dog IR @ Tractor Supply.
I gave it a long, long, long hard look since I was already at $299 for the 4 gal hot dog.

Alas - I need portability more than I need air volume.

Still - it was tempting....

[Ray Newman]

Yup definitely check out the duty cycle.

[John Denture]

Well the tax man has come and gone and I still have some skin left, sooo...it's time to buy a tool.

My trusty 10 year old Air Charge (aka Devilbis) 4hp, 12 gal portable has given up the ghost. I'm not sure exactly what happened with it but it might have had something to do with excessive acceleration on an on-ramp with the tailgate in the down position.

I bought a small nailing compressor which has gotten me by (Hitachi - which is a nice machine BTW, but that's another subject). Anyhow, it's time to bring in a stationary machine.

I've pretty much settled on the IR, 60gal, 3hp unit ($629 @ Tractor Supply)that's so popular with a lot of folks here at the Creek. This is unless sticker shock gets to me at the last minute and I go for the CH @ Lowes ($400). If ayone can convince me that I'll be as happy with the CH as the IR, you'll save me a bunch of money.

The CH cast iron, oil lube compressors, are, to put it mildly, not built to the spec they were a few years ago. I do happen to own an older Husky branded unit manufactured by CH, twin cylinder, that believe it or not has a 100% duty cycle rating on the compressor and a TEFC US-made Emerson continuous duty motor. The new ones have 50% duty ratings or less and I've seen them spin bearings and burn up reed valves in under 100 hours of operation.

I think that the relatively small price difference will fade away quickly, but you'll definitely appreciate the higher CFM and greatly increased longevity of the IR- plus you'll be able to buy parts for it if it ever has problems.

So, my thoughts and questions are:

1) Mounting - There seems to be two schools of thought here. Most bollt into the floor with vibration isolators or hockey pucks between the machine and the floor. The other school just leaves it bolted to the shipping pallet. I'm leaning towards the latter mostly due to laziness. Any thoughts pro or con on this?

An isolation base will reduce noise and vibration but it's not really necessary. If you're in earthquake country, you might want to consider bolting it for other reasons though...

2) Plumbing - I've got a design in mind using 1/2" black pipe. The compressor is at one end of the system and the painting station is at the other. In order to keep moisture out of the tools and especially the paint, I was thinging of putting a filter at each end. Given that I spray mostly water based and shellac is that even a big deal. Also the CH2121 filter (~$27) is about the only thing carried locally. Is that going to work or should I order something more substantial?

I personally like Wilkerson. Keep in mind that cheap dessicant dryers will deposit debris in the output stream. I generally run system pressure high enough that I can have a dessicant dryer and coalescing filter after a long run (where moisture will condense out), followed by a regulator and pressure gauge so I can get exactly what I need at the tool. Don't try to put a single regulator at the compressor, then run 50 feet of pipe, dryers, etc.- there will be a significant pressure drop. Also consider pipe diameter and your CFM requirements at the end of the run.

You might consider a moisture-minder type of automatic drain / purge valve.

3) Pipe connections - Some where in my research I read that teflon tape isn't up to the pressure of an air system and recommended pipe dope for a leak proof system. Has anyone had a bad experience with the tape?

The only reason you'd need pipe dope is if you have badly cut iron pipe- unfortunately that's about par for the course nowadays with cheap Chinese pipe and fittings taking over the market. I have plumbed entire shops with Grinnell fittings and pipe and had a system that would hold 120PSI for weeks with just a couple of turns of teflon tape. Last I tried with Chinese fittings and copious amounts of teflon pipe dope, after tearing my hair out, I tore out the pipe and put in PVC- the pipe was that bad.

[James Manning]

I got the 60 gal IR from TS about yr ago, jump now or wait for a sale at TS.........either way the IR is your best bet IMHO.

[Jerome Stanek]

If you can find a 2 stage IR go for it. We burned up 2 of the cheaper IR single stage IR's before we got the 2 stage in our sister shop. They thought that the single stage was the same as the 2 stage in our main shop.

[Robert Reece]

As far as pipe dope, I don't think it is necessary. I just put together a system with probably 100 joints and I used tape. I found the magic number of wraps to be about 8. It holds 175 psi. Just pick up some leak detector and put it on your joints. Check them after a little while 15 min or so and you'll be able to see any leaks as a big pile of bubbles.

Also, be careful with any filters. After stressing out about my system leaking, I finally took out my filters and pressurized them outside the system. When I put them in water, sure enough they were the ones leaking. The manufacturer is still scratching their head trying to figure out why every filter they have won't hold 150 psi. In my opinion, it's a design flaw. The filters are sealed with an o-ring that just isn't up to the task.

[CPeter James]

Last I tried with Chinese fittings and copious amounts of teflon pipe dope, after tearing my hair out, I tore out the pipe and put in PVC- the pipe was that bad.

While it would appear the plastic pipe would be the thing to use, PVC, CPVC, or PEX and all other readily available, inexpensive, easy to install plastic tubing and pipe are not rated for compressed air. Not only are they not rated, they are expressly forbidden by OSHA. The hazard involved is flying shrapnel if a break occurs. The plastic becomes brittle over time and if is bumped, it can explode.

Copper pipe comes in several grades that are normally available in local plumbing supply houses, hardware stores, and home stores. Type K is a softer bendable pipe and very expensive. Of the two grades that are sold in 10’ rigid lengths, only the type L is suitable for use in compressed air systems. Type M is intended only for use on hydronic (hot water) heating systems. Type L is labeled with the blue printing on the pipe or it is stamped into the metal. It should be silver soldered together for maximum joint strength. Copper is easy to use, easy to reconfigure, and fittings and pipe are easy to obtain, even on a Sunday afternoon should the need arise. The downside is that copper is relatively expensive to purchase and the cost can be substantial if the runs are long.

A good compressor and a properly installed system will serve you well for a long time. Just do it right and don’t be tempted to take unsafe shortcuts. PLEASE BE SAFE, DON’T USE PLASTIC PIPE!

CPeter

[Larry Nall]

As expected, no one even tried to talk me out of it and I didn't chicken out. The IR is now sitting in the shop humming away. Well, not exactly humming but a lot quieter than my old oilless.

Question, on teflon tape, someone recommended a couple of turns, someone else mentioned eight. Is there a rule of thumb here? I've never done more than two or three wraps but that was with water.

[david scheidt]

2) Plumbing - I've got a design in mind using 1/2" black pipe. The compressor is at one end of the system and the painting station is at the other. In order to keep moisture out of the tools and especially the paint, I was thinging of putting a filter at each end. Given that I spray mostly water based and shellac is that even a big deal. Also the CH2121 filter (~$27) is about the only thing carried locally. Is that going to work or should I order something more substantial?

3) Pipe connections - Some where in my research I read that teflon tape isn't up to the pressure of an air system and recommended pipe dope for a leak proof system. Has anyone had a bad experience with the tape?

Larry

If you can, run a loop of pipe around the perimeter of the shop. pitch the pipe (1/4" per foot) so that corner nearest the compressor is the lowest point. Put a drain there. Install more air drops than you think you need (you don't have install all the piping for drops you're not using, but if you put in the T-fitting and a stub of pipe with a cap on it, you'll be much happier when you decide you need it.) Point T-fittings up (keeps liquid water out of the drops). Run the drops to t-fitting, put the outlet on T leg, and put a ball valve and drain on the other.

Use good quality fittings (from a plumbing supply shop; not the borg). Use liquid/paste pipe dope, not tape; it's easier to use, works better. It's marginally more expensive, but enough to do every pipe you're likely to do for the next decade costs ten bucks. (RectorSeal is a good brand; it's the only one my plumbing supply sells.)

[David Freed]

I have a 6 year old Iron Force, 5hp, 60 gal made by CH that I used in a commercial setting for 3 years. It has a 100% duty rating for 5000 hrs. I let it run out of oil and it locked up solid about a year ago. I took it apart, freed it up and put it back together with no new parts and it is still running like a new one. I am now running straight Lucas hub oil in it now, which is about the consistency of thick molasses. I can give details on how I unseized it if anyone is interested.

[Thomas Allan]

I'm under the impression it's better to have 3/4" pipe for the runs and 1/2" pipe for the drops, the former allowing volume and the latter allowing pressure. Better yet to even have a 2" diameter (holding) pipe as your 'upfeed' (if your system will run above) coming out of the compressor.

Another vote here for pipe dope over tape.

And another vote, too, for a rise before each drop.

[David Freed]

I'm under the impression it's better to have 3/4" pipe for the runs and 1/2" pipe for the drops, the former allowing volume and the latter allowing pressure. Better yet to even have a 2" diameter (holding) pipe as your 'upfeed' (if your system will run above) coming out of the compressor.

I agree with the idea, but that isn't exactly how I would phrase it. The larger pipe helps reduce the pressure drop over long distances. 200' of 1/2" hose would have a noticeable pressure drop as compared to 190' of 2" pipe and a 10' long 1/2" hose. Also 190' of 2" pipe gives you 27 gallons of volume as compared to 6.5 gallons in 190' of 1/2" airline. 3/4" pipe gives you about 15 gallons.

[david scheidt]

I agree with the idea, but that isn't exactly how I would phrase it. The larger pipe helps reduce the pressure drop over long distances. 200' of 1/2" hose would have a noticeable pressure drop as compared to 190' of 2" pipe and a 10' long 1/2" hose. Also 190' of 2" pipe gives you 27 gallons of volume as compared to 6.5 gallons in 190' of 1/2" airline. 3/4" pipe gives you about 15 gallons.

In industrial set ups, it's not uncommon to see a section of oversized pipe near bursty loads. An automotive shop I used to work in had a loop running around the shop, in 2" pipe. We had two identical tire machines, at opposite ends of the shop. One was quite near the compressors (two 7.5 hp 175 psi units. We used lots of air...), and just had a 3/4" drop, to a hose fitting. at the far end, there was an 8" pipe serving as the drop. That machine was much nicer for seating beads, which requires large quantities of air. (The thirty foot drop was about a 40 gallon surge tank. )

Depending on what you're doing, 1/2 pipe may be fine, but bigger is better, assuming you don't have leaks.

[Chris Parks]

I'm under the impression it's better to have 3/4" pipe for the runs and 1/2" pipe for the drops, the former allowing volume and the latter allowing pressure. Better yet to even have a 2" diameter (holding) pipe as your 'upfeed' (if your system will run above) coming out of the compressor.

Another vote here for pipe dope over tape.

And another vote, too, for a rise before each drop.

The reasoning behind the biggest pipe you can get is the air speed is lowered and when that happens the moisture drops out of the air. There are modular systems that work on this principal, they are clip together and you can pull them apart. I will never use screw or solder piping again. Have a look at this....

http://www.rapidairproducts.com/