Air supply solution ..

[Rick Fisher]

Hey ..

A while back I posted about having huge pressure loss trying to run a pneumatic Kreg DK1100 on a 25' x 1/2" hose. Basically the pressure would drop almost 50 PSI in the cycle and the machine was not cutting well at all..

When I spoke to Kreg, they said the air hose was a deal breaker .. it needed less than 10' of hose, or another source of air supply .. I tested it with 5 feet of hose and it worked great.. so I agreed that a 1/2" x 25' hose could not keep up with the pneumatic motor in the Kreg machine.

Not wanting to have the Kreg machine right by the compressor that feeds it, I decided to run a 25 foot hose to an old 2 gallon tank off an old Speedaire hot dog compressor .. I rigged so its a holding tank being supplied by the big compressor..

The results are awesome. It meant putting a regulator right at the Kreg machine, but 2 gallons of air connected to the Kreg with about 15" of 3/4" Pex is more than ample to cycle the Kreg..

Each cycle, the holding tank is replenished through the prior insufficient 25' hose and I can drill kreg holes as fast I the machine will cycle..

[Trent Shirley]

Nice solution Rick.
I would have suggested running hard pipe to the Kreg machine but I am not sure if the result would have been better or not. My assumption is that the drop in pressure is related to the stretch in the hose under pressure and running some pipe to the area to carry the air would stop that pressure drop. This is something I need to do with my compressor to get an outside line as it is too large to be rolling around all the time and I hate leaving the shop door open with the hose running through as it lets all the humidity back in the shop that the dehumidifier works so hard to get rid of.
I need to look into a heat vent pipe for the dehumidifier also, it warms the shop up too much.

[Bill White]

Didn't know that Pex would handle the air pressure. Good fix.
Bill

[Matt Meiser]

I installed some PEX in my shop largely as an expiriment (in fact, it was to feed my Kreg machine) and it seems to be working well. There's only a few fittings to plumb a drip leg and regulator after it branches from my existing copper main line. And since it goes up to my 12' ceiling and across the shop it was a LOT easier to install. I need to run another to my finishing room, which will probably also involve a drop in the storage area for airing up tires on the equipment out there.

[Trent Shirley]

Remember that Pex begins breaking down when exposed to light especially sunlight and fluorescent light. It will begin to become more rigid and brittle and ultimately could throw lots of Pex shrapnel if it gave out under pressure.
Under constant load it would most likely begin to leak first but under a cycled pressure it could give out all at once.

[Bruce Wrenn]

We use "booster tanks" with our framing guns when compressor is located some distance away. We use an old 20# propane tank, as it takes a standard 3/4" NPT fitting. Yes it's rated for more pressure than we run.

[Peter Quinn]

I like it. I put a 5 gallon tank on my vacuum bag, same idea in reverse, man does it suck down. I have an old 25gal tank sitting in my external garage waiting for a few round tewits, then it will act a storage tank for the compressor in the basement shop about 75 feet away, maybe a 3/4" hose? I had a decent old emglo parked out there but a friend needed it more than I did, so I donated it. Glad to here your machine is working well, nice fix. I'd rather see a braided stainless supply line than pex personally over the long haul. Not sure I trust plastic on air systems over time? I used a 24" braided stainless hot water tank supply line to hard plumb my compressor to the copper line that feeds a spray room, seems to work with the right brass, rated for 200psi and several hundred degrees!

[Rick Fisher]

I think the Pex will be temporary.. I am going to build a new SCMS bench and want to build the Kreg Machine into the bench.. When that happens, I will get a higher grade of supply line.

Its amazing to me how much air that machine hogs when running.. The compressor is a real 5hp and the Kreg can run it out of air with the compressor pumping.. Its not a problem because it takes dozens of repetitive cycles.. I could not do it while working, more of a test..

Now that its running .. its an efficient way of making pocket holes.. Fast, simple and clean cuts..

[Peter Quinn]

Geez, I just reread the title of this post and started thinking "Any time I am hearing Air Supply on my radio, its a problem......"

[Ronald Blue]

In essence you installed an accumulator. In hydraulic systems they are used to maintain the pressure while the pump reacts to the demand. While there is no bladder in the reservoir it is still stored energy that is immediately available as needed. That's a great idea and fix.

[Larry Edgerton]

I ran into a problem like that at my old shop. The shop was 148' long with the compressor by the panel at one end.
My solution was 2" black pipe air lines running down both long walls and regulators at several locations.
At each drop there was a mud leg with a drain before the regulator, and the lines had an 1/8 of an inch per foot pitch so an water would drain to the mud legs.
I kept the compressor set on 175psi, the large lines served as an additional air tank.
I am not a fan of plastic, but that is just me. What an air line can do when it blows is scary.

Larry

[Andrew Arndts]

I only glanced at the title and my first thought was to use anything by Air Supply as targets at a firearm range. Then crank out anything by the Doors, Led Zepplin, Alice Cooper (almost Halloween) Ted Nugent..... Or Bach, Beethoven, Brahms, Booker T and the MG's....

Sorry, it is 3am, insomnia is really bad right now.