Shoebox Compressor Fun

[ezman604]

Story time...LOL
We had 3 different divisions here at work. One was Fire & Rescue sales and service. We were a distributor for all kinds of gear, from fireman boots up to and including specing out and selling fire trucks. We had a HyPres compressor system we paid $17,000 for to service and fill SCBA cylinders. Well, the boss decided to close this division since the sales in this area have been dropping off steadily. So last December we officially closed the doors of this division. I was given the ironic task of finding a buyer for the HyPres system that I used to fill my SCBA airgun cylinders with.
The good part is when I did sell it, the boss gave me a commission which I used to purchase a used Shoebox compressor.
It had the upgraded belt drive kit as well as the hardened piston upgrade. I have had it sitting in the box for a few months, not even take out to play with it. One of my 4500psi cylinders was down to 2850 thanks to me getting acquainted with my .25 Condor SS so I HAD to set the Shoebox up to refill. I was told this unit had VERY little use and I believe it. Thing looks new. I set it up and proceeded to fill my cylinder. After about 45 minutes running the belt broke. Darn...found one online and ordered. After the belt came in, I installed and checked out the overall operation of all moving parts. I read the manual and performed the routing lube of the pistons. After firing it up to press on with my 4500 cylinder fill, I noticed the cylinders of the compressor get extremely hot. I put a floor fan in front of it that really cooled things off. It took about 3-1/2 to 4 hours to fill my cylinder to just over 4500psi.
Two things I noticed and want to work on, being the tinkerer I am. LOL
The unit has a kicker type shut off system. A spring loaded striker hits the on/off switch with every stroke of the pump. As the pressure builds, the striker is supposed to hit the switch harder until at around 4500psi the striker is supposed to trip the on/off switch shutting the unit down. While this unit is running, I could not stay in my shop for a prolonged time without ear protection. It's just too annoying. And while I watched and my cylinder went over 4500psi, the Shoebox did not shut off. I know it's adjustable but it got my brain to ticking kinda like the striker was doing. 
The first thing I looked for was a cooling fan. Fortunately, this Shoebox was a production run that Larry had already set up with a fan installation location with all of the holes drilled. I just searched eBay (my second home) for an 80mm 110v ball bearing fan. I have that and installed. Next I searched and found a 4500psi pressure switch. My plan is to find a "T" to install somewhere in the output air line to install this pressure switch. This will eliminate the annoying kicker assembly as well as give me the assurance  this unit will shut off at 4500psi. If it goes too much over, my fear is it will over pressure and blow a burst disk in either the compressor, fill assembly or the cylinder itself.
I sent Larry at shoeboxcompressor.com a message asking his thoughts on the proposed mod. Then I went to his website for some more reading. And low and behold, have you looked at the new Freedom 8 compressor? LOL
Well, it is $1100 but it has some GREAT improvements. Besides cutting the fill time in half, he has incorporated a pressure switch into the new compressor and eliminated the kicker system. THAT new compressor would be awesome with the improvements he made!!!!
So, after I get mine modded, I MAY offer it up for sale and bite the bullet to get a Freedom 8. I am very impressed with the quality of this home unit especially for the cost. And in watching the videos he has posted, maintaining it should be very easy.
Okay, end of story. If you have been debating on a Shoebox, I suggest you go for it. Especially if there is no close access to a refill station. Maybe 2 or more GTA members can share the cost if you live near each other. Just a thought. Now I'm off to shoot till I run out of ammo. No worry now about running out of air.
HeeHee
SAFE & Happy Shooting!!!!
Dave
 
 

[Sfttailrdr46]

  Talk to sciguy he has a huge stash of boxed crosman pellets 17,500 that he scored maybe if he is in a good mood he'll share

[Norm_m]

I've had my Shoebox since they 1st came out and have been updating it anytime new models with improvements come out. The 1st mod was to add a fan to the left side, covering the holes on the cover with tape and drilling new holes on the right end. This forced the air to travel the full length of the pistons to help cool them better and at the same time some of that air is sucked through the motor helping to cool it. Next came the belt drive soon followed by the hardened pistons and changing the original high pressure cylinder to the new style with the cooling fins. The last mod was to install a high pressure switch, which accomplished several issues. The 1st was to do away with that clankady clankady clank noise of the original pressure switch. Next was the ability to fine tune the shut off pressure and last was the ability to increase the 1st stage air supply from the oil less shop compressor to as high as it would go. By increasing the 1st stage air pressure I saw a huge change in the time it takes to fill my tanks. It did not cut it in half but very possibly cut it by a third.
The switch and fittings for the electric high pressure switch all came from McMaster Carr

Norm

[Motorhead]

Having a SB myself ... could not agree more on the annoying Clicky Clack of the rocker knuckle at higher pressure.

** But be aware this devise while looking real rinkie dink is in fact quite ingenious because it SENSES RESISTANCE and not pressure.
BLOW OUT a 0-ring on HP cylinder and LP side gets over loaded and rocker trips switch OFF.  Same for loosing an o-ring on LP cylinder.

This keeps compressor from running indefinitely unable to obtain a pressure that an inline pressure switch also would never sense shutting it off.

Just an FYI Dave ...
Scott

[ezman604]

True that and thanks for the info. BUT, after watching the compressor, it did not shut off at 4500 and actually almost 4600psi before I manually shut it down. I'm more worried about the opposite of what you describe in that if it doesn't shut off, it will over pressurize and blow my burst disks. And look at the F8 compressor, they have even done away with the klacker for a pressure switch.

To be able to stay in my shop while it runs and know it's not going to over pressurize, I personally think I'm going the pressure switch route. And after looking at how they attached it in the F8, I may just drill and tap my distribution block around the outlet for the pressure switch to screw into.
But excellent info, keep it coming. This is all new to me and I'm still learning.
GREAT job Norm!!!
Liking your setup. I'll take a look at the vent holes in mine, I don't recall any in the cover at all. I may mill or drill press some in the right end to get the cross ventilation you described. If you can remember or have the time, can you post the list of part numbers to do the pressure switch mod?

[Motorhead]

Just an FYI ... I set my Trip point a tad above 4.5k typically filling to @ 4700# before tripping off.
Tank cools a tad generally settling in right on the money @ 4.5K 

[ezman604]

Hmmm...again, true that.
I pumped to 4300psi last night then shut down for bedtime. When I went back to check, it settled to around 4100psi, I assume after cooling a tad. I may be just a bit too cautious. Will let it rip again and see just WHERE it shuts down and settles to. But still, the clackity clack has gotta go.

[krrtlr1]

I have decided that I want to upgrade my unit also. I haven't received it yet, but wanting to get all my supplies in line. Is there anything special I need to hook the pressure switch into the circuit? Also thinking of adding the fan. Is it 110 volts on the on/off switch side of the motor or does it step down.

Thank you!

[FuzzyGrub]

Very old thread!    Best to start a new one.  The max is not available any more, and if you bought a Freedom, it comes with the adjustable pressure switch.

If you bought a used Max, then switch, wiring, relay, plumbing, and defeat knocker.  Can go into more details if you need them in a separate thread. 

[ezman604]

Yeah, I haven't had a Shoebox in years and can't be much help with advice. Except to contact Tom @ http://www.shoeboxcompressor.com/contact.
He's a super guy that goes above and beyond with support!!!

[oenomaker]

Yeah, I haven't had a Shoebox in years and can't be much help with advice. Except to contact Tom @ http://www.shoeboxcompressor.com/contact.
He's a super guy that goes above and beyond with support!!!

Tom is a great guy when it comes to support, but my couple of questions about modification fell on deaf ears.  He essentially told me to sell the unit I had and upgrade to a newer unit with the features I desired (I had asked the same questions).  Not that I blame him because instructing someone how to modify his product could backfire on him tremendously if somebody got hurt in the process and he got sued.  The Freedom 10 is on sale for $500 right now which is less than I paid for my MAX when I bought it.  It's way faster and has the pressure switch.  I'm thinking about buying one myself and letting my MAX go for $350 or so....

[krrtlr1]

Hey Guys,
Thank you for the comments. I knew I was taking a chance, but liked the pictures posted above. Toolmaker by trade and tinkerer by hobby, so not scared of the mechanical side. Just kind of flustered by the switch and SPST vs SPDT and normal on vs off.

I will start a new thread.

Thanks again.

[Back_Roads]

 OK never mind my post on the new post then