29 March, 2014

Under pressure times two...A reely big issue for me.

As you have seen from my shop tour, I own 2 air compressors. Both Harbor Freight / Central Pnuematic units, and both are oil less units which makes them nice and quiet in the shop...

Now I own a Harbor Freight "Earthquake" 1/2" impact wrench, which is based off of the Ingersoll Rand 232 Thunder design. A decent enough impact wrench, but it calls for 6 CFM, and on my 29 gallon compressor at 5.9 CFM, I am wondering if it is air flow or a bad gun that is causing low power output from my impact gun...

To top it off, I picked up one of the 50 self retracting hose reels from Harbor Freight on sale. I see these all over the place, woodworkers, car guys you name it use them. They are well regarded, except there seems to be some disdain for the hose itself. Then again, I did not buy this for the hose, but rather the reel itself. With one of these I can keep the air hoses out of harms way, you know, not tripping me and killing me. Not to mention making it FAR easier to pay out hose and with sufficient length to get to where I want to go across the drive...

My actual reel, connected to the main feed hose 
and waiting to be installed. 
You can also see the Earthquake gun in the background.

Now I know I am just barely under the required CFM for my impact wrench with the 29 gallon compressor, and I am concerned that the reel will render it useless. FYI the Earthquake 1/2 in impact flows at 6CFM @ 90 PSI, the HF 29 gallon 250 PSI compressor flows at 5.9 CFM @ 90 PSI. It works for intermittent use, but needs some added oomph. Espeically since I am considering adding an air sander to my arsenal for things like wet sanding the car for paint prep. 

I have the HF 8 gallon 2HP 125 PSI compressor sitting under my dust collector, which can be put in tandem with the 29 gallon I think... That compressor develops 4.5CFM @ 90 PSI...

I am thinking, perhaps incorrectly, so help me out here guys... that I need to regulate the big compressor to 125 PSI, keep the 8 gallon wide open, and then connect the two to the whip tee. 

At the tee, I can add a separator / filter with regulator (already have one, and regulate it all down to 90PSI or whatever the need may be... (None of my pnuematic tools operate over 90PSI, and spraying is even lower, MUCH lower...

So the specs for the compressors are.

29 gallon compressor. Central Pnuematic Item#68127
CFM @ 90PSI = 5.9 
CFM @ 40PSI = 7.3

The 29 gallon is close to doing it all,
just not quite there!

8 gallon. Central Pnuematic Item#69667. (Actually the earlier model that is pretty much exactly this compressor, but it has a plastic handle instead of the steel hoop).
CFM @ 90PSI = 4.5
CFM @ 40PSI = 5.5

It's hard to see, but the little 8 gallon
compressor is down under that stand!

Theoretical combined totals. It is understood that the total CFM numbers should be somewhat lower due to losses in the plumbing.

Tank storage. 37 gallons.
CFM @ 90PSI = 10.4
CFM @ 40PSI = 12.8

To make the tandem connection I have a simple 1/4" NPT female brass tee fitting similar to http://www.summitracing.com/parts/var-92855/overview/ however the one I have is female on all outlets, and is quite old. I salvaged it when a shop I used to work at was bulldozed during a remodeling project. 

I have several of the 1/4" brass pipe nipples as well from the air compressor accessory kits I have had over the years. (I buy the kit when I need a blowgun I don't really care about but I know will work...)

I have a 3/8" in line air filter with regulator Central Pnuematic Item #68232.

Uncounted number of male and female I/M quick connect fittings. Mostly Harbor Freight but some Milton and others who knows what. Verified leak free... The leakers get tossed or returned.

While I was at Harbor Freight I picked up an 8' 3/8" rubber hose with 1/4" NPT fittings as well as the 3' version of that hose. Sorry I couldn't find it on their website. 

I also picked up a 50' 3/8" PVC / Rubber blend air hose with 1/4" NPT fittings. I am not linking that one, I do NOT recommend that hose, it is going back as soon as I can get to Harbor Freight...

Lastly I need a stand alone pressure regulator mostly to verify the upstream regulators at the end of the hose. The Central Pnuematic 150PSI unit should do the trick.

The idea here is to..

Project #1. Using pipe thread tape on all male threads I will assemble. Nipple to tee. Tee to inlet of filter / regulator such that tee is vertical. Female quick connect to bottom port of tee. 8' whip to middle port of tee, and 3' whip to top port of tee. Attach to wall next to larger compressor, out of hte way of toolbox drawers. Set regulators to the same pressure. Attach male quick connect to ends of hoses, and attach hoses to compressors, and test. I have done this, and found a bit of a failure. When connected to the tee, the 8 gallon compressor / regulator appears to be getting some backwards pressure, and is bypassing air. I have ordered check valves for both compressor lines to prevent this from happening. It could potentially be a problem of the cheap regulator on the 8 gallon. The OE Harbor Freight regulator broke a few years ago, so I replaced it with a Husky regulator I got at Home Depot... I have never been thrilled with it...  I am considering also removing the ball valve from that line and going straight with the quick connect It is however nice to be able to shut that line off / isolate it if I want to.

The darker red hose goes to the 29 gallon
The lighter red hose goes to the 8 gallon
The lime green hose goes back to Harbor Freight!
I will be grabbing a 25' rubber hose instead.

Project #2. Install hose reel to ceiling braced on a wood mount board and that in turn lag bolted the the trusses, 16" O.C. See LCHIEN's install photo at the beginning of this article. I plan on copying his install method sort of. Mount board, check, bolts run through mount board prior to install, check, then it goes different. I am going to use carriage bolts, epoxied into place, and nuts will be run into the back 2. Mount the board to the ceiling trusses, studs, whatever they are called, and then I will push the slotted holes over those bolts, and let the mounting plate rest on that. Push the non slotted holes over the other two bolts, start the nuts and then run them home... 

Project #3. The 8 gallon was rigged a while back this way, but the OE 1/4" NPT petcock valve was removed from the bottom of the tank, a street elbow, a nipple long enough to get all the way out from under the tank, and a ball valve were added for easy to do, and easy to predict the behavior of tank draining. Copy that setup on the 29 gallon. I already have the spare ball valve. Just need the street elbow and a sufficiently long nipple. How long that is I am not sure at this point...

Mind you, I am trying to drive the following tools...

1/2" impact wrench. 6 CFM.
3/8" Air ratchet. 6 CFM.
Air Hammer 3 CFM
HVLP spray guns. 6 CFM
Siphon spray gun 1.5 CFM (I do NOT believe this number, this is MFG supplied, and appears VERY VERY wrong...)
Siphon spray gun 9 CFM @ 40 PSI.
Dual Action Sander 4 CFM.
Nailer / Stapler .5 CFM
Framing Nailer 3 CFM
Finish Nailer 1.5 CFM
Pin Nailer .2 CFM
1/4" die grinder 3 CFM

IF I can get this rig working according to the theory, and get the feeder hose situation squared away, this setup should serve me well for years to come. However I must admit, once these compressors die, I will likely swap them both out, and grab a 220V 60-80 gallon compressor, and run copper pipe up to the hose reel.

1 comment:

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