Shoebox Max initial performance numbers

[Case Stuffer]

New SB Max with hardened pistons, auto lubication , belt drive and the fan upgrade arrived yesterday. Porter Cable C2002 (6 gallon tank) used as first stage ,turns on at 120 and off at 150PSI , runs for 30 seconds every 15 minutes while supplying 90 to 95 PSI to SB.

Guppy - 17 Cu. Ft.(118 Cu. In) rated 4.5K

0.5 Hr. 500 PSI
1.0Hr. .2K
2.0Hr - 2.4 K
2.5 Hr. 2.8 K
3.0 Hr - 3.7 K
3:35 - 4.4 K


Top off from 3K to 4.4 K 1:05

Direct to Discovery 1Kto 2K 4.5 min to Mid yellow ,bleed and gauge reads 2.0 K.


Very pleased with results which are better than what I have read on the forums where most state 6 hrs. to take a Guppy from 0 to 4.5K.

[Case Stuffer]

During the past six days I have sent just over 200 pellets down range and my little 17 Cu Ft Guppy CF tank had dropped from 4.4K to 3.2K so with nothing better to do I topped it off. It had been suggested over on the Shoebox compressor forum that increasing the input air pressure to 125 instead of only 85 PSI would boost performance. I set regulator on shop (oil less) compressor at 115PSI and 3.2K to 4.4K top off took just under 45 minutes.

Really enjoying this no labor PCP shooting and fully understand why so many on other forums posted about how their pellet bills went up after getting away from hand pumping or having to make trips to get tanks filled.

[sixshootertexan]

Yes my pellet bill went up after getting my Ninja tank and making trips to the paintball field. Now it's about to go up more as soon as I finish building my compressor.

[jmorris]

What is your "all in cost" for the shoebox, oilless compressor, tank and valves?

[Case Stuffer]

Too much , Shoebox was $649 base but I added fan mod. , a deluxe (complete / numerious ) rebuilt kit for cylinders with spacers,the Guppy 17 cu ft tank with duel gauges,and 40" micro hose with duel female quick disconnects was like $389 then $55 shipping plus insurance an signature required for a total of $1,291.47 . Porter Cable C2002 oil less compressor was on sale at Home Depot for $100.

That is why in one of my post I stated that support for my Disco was many times greater than its' cost. This is also why older SCBA tanks and the fill station (manifold with fittings and gauge) from Air hog is such a bargain. The 87 cu ft tank I have ordered ( from E Bay)was $140 shipped and the Sports Filling Station( from Air Hog) as just over $140 so about 70% of what the Guppy cost but five times as much air storage. Adding additional SCBA tanks is cheap enough as there are always expired or close to expired ones on EBay.

Second tank set up is fluff and means that I will only need to run Shoebox on rare occasion as it should fill Disco from 1.2K to 1.8K around 170 times which is more than I would use in a year.. I am somewhat planning ahead so that if / when I go to larger caliber I will be set air supply wise.

If one was on a tight budget Shoebox can be used to fill gun directly but who wants to run down to the shop for each fill. I shoot off of my back deck mostly and shop is 120 ft. away and is hot by 10 AM this time of the year and cold in the winter.

[Case Stuffer]

My SB Max is two weeks old and have used it to fill a 17 cu ft Guppy tank to 4500 and to trop it off from around 3000 to 4500 several times .

First time filling a Papa Bear size.

Chart shows 12 Hrs. to fill a 44 cu ft from to 4500 which would equal 23 hr and 42 min.for a 60 min / 87 cu ft one.

Scott 60 min. / 87cu ft SCBA . Starting at zero , filled at rate of 300 PSI per hour . Not close to 300 per hour but exactly (well as close as I could read the gauges) and both the SCBA gauge and the gauge in the fill manifold matched through out the whole range..

2hrs. 600
3hr. 900
4 hrs. 1200
etc. each hour and yes I checked withing one min. each hour and logged the results.

At 14 hours and 25 minutes 4,500 it had not cut off so I shut if off.

I did this in three runs . First one 3 hours , next 9 hours. I drained moisture from the shop compressor each time and there was not that much and also bleed SB and tank fill hose using the SB valve. SB ex spelled just a trace each time.

[jmorris]

Interesting that there was zero change in time it took to compress from 600 psi all the way to 4500 psi.

With 14.5 hrs run time, do you have a timer on it or any kind of pressure switch?

[Case Stuffer]

I had a digital kitchen timer set for 60 minutes and I was also checking my watch and each hour I made the one minute walk down to the shop read the gauges , logged results, took temperature reading and did an overall visual check.

To me the steady 300 PSI per hour increase just shows that there were no mechanical issues during the 15 hours. No air leaks at connections or valves,no Shoebox seals leaks, constant input from shop compressor, fairly consistent air density . Shop compressor only runs 30 seconds every 15 minutes and has a 6 gallon tank so steady air temp. here , Shoebox had 12" box fan cooling it and I did not run the set up during the hottest part of the day. Highest temperature I recorded on the Shoebox cylinders was 112F and 40" micro line going to cylinder never went over 95F and that was within 6" of the Shoebox's output.

Yes I am a bit anal about monitoring equipment and recording results to be used as a base line in the future. I designed, build and maintained an array of manufacturing equipment for ,many years .

Do you have any thought on other reason fill rate should vary?

[jmorris]

Do you have any thought on other reason fill rate should vary?

It is fairly common for compressors to deliver smaller volumes of air at higher pressures.

Like your PC C2002 for example it delivers 3.5 CFM @ 40 psi and 2.6 CFM @ 90 psi. Thats only a 50 psi difference to vary the flow rate.

Understanding it is not an apples to apples comparison as the two compressors are quite different, I still find it interesting compressing an additional 4000+ psi makes no difference at all.

[Case Stuffer]

It is fairly common for compressors to deliver smaller volumes of air at higher pressures.

Yes it is however the C2002 creates a lot of hot air and the hotter the air the thinner it is. Surely you have a decent size two or three stage shop compressor. Use an IR temp. gun and check head temperatures sometimes after it has been running for 5 minutes or so.

The Shoebox Max is very slow and steady and with a decent amount of cooling air flowing across the cylinders and manifold block it just not heat the air much.

When I was using my Benjamin hand pump I noticed a different in fill rate with different stroke speeds and breaks between groups of strokes. Fills from 1K to 2K seemed to be best using very moderate speed strokes, pauses at each end of strokes, 5 strokes to pressurize the line then 10 strokes ,pause for 30 seconds 10 more strokes ,pause and repeat. 55 strokes for a fill. If I pumped non stop it took more strokes the pump got warm and it generated moisture .

[Case Stuffer]

Here is higher performance HPA compressor with a constant fill rate of 1K per hour but it is water cooled.

http://www.airtanksforsale.com/alpha90/

Snip:


It is a stand-alone water cooled unit that will top off our 71 Cu Ft (410 Cu In) Tiger Shark tank from 3000 PSI to 4500 PSI in ONLY 1.5 Hours and fill it from EMPTY to 4500 PSI in ONLY 4.5 Hours. The unit is completely self-contained, so no extras are needed. (And I measured the time to fill myself.)


note

And I measured the time to fill myself is vendor's statement .

I seriously considered one of these but it cost twice as much as Shoebox Max but is just over three times as fast.but I have a lot more time than money. The alpha90 is a lot better value than the Shoebox Freedom 8 IMO as they are very close to same price but alpha needs to have water traps drained about every 15 minutes .

[Case Stuffer]

A few photos.

147490
Improved (clear) desiccant / air dryer.

147491

Now running ShoeBox input at 120 PSI and it does increase out put.

147492

12" Box fan provides extra cooling. Pressure cut off switch is safety wired so it no longer functions thus no more clacky-d-clack and this seems to increase out put also. I time the run times ,set a timer and an alarm.

Red cylinder is a Diablo Dry Air System which I do not really believe is necessary but while there was very little moisture before there is non now.

87 cu. ft. CF 4500 PSI SCBA tank on top shelf is my reserve and makes a nice hose hanger.[smilie=s:

Last run this morning .

12 min. to fill Diablo and hoses to 3,000 PSI then 58 addational minutes to fill Guppy 18 cf from 3,000m to 4,500.