KalNet Message Board

http://www.shoeboxcompressor.com/

It doesn't look like it's all that fast, but it is a home solution that is way more affordable than what's already out there.

This one's cheaper...



[EDIT: and its smaller too]

um... HIGH PRESSURE compressor.

hah

Based on my understanding of that overflow (or is it cascading?) system, it would be a good way to go. Couple of big tanks filling over a day or two then feed the small tanks as necessary.

I had such high hopes that the compressor at the family farm's shop would work, its good enough to hit enough pressure on a tractor tire, hoped that it would be sufficient for a little 12 oz tank... ah well.

Seems like the fill time is pretty long, but if you had a scuba tank to hold the fills it probably wouldn't be too bad.

Or just fill everyone's tank throughout the week.

Since most people are migrating away from HPA I don't think it would be worth the investment, but I thought it was cool.

I would be interested in the power consumption figures.
Cost per cubic Inch etc. to see how it compares against a faster compressor.
Also to compare it against the cost of a Fill at a Pro-Shop.

If it was around $100, I'd go splitsy with ya.

But over 1/2 a grand? No.

I'd find out what scuba shops fill for a tank fill before that. Used scuba tanks often go cheap. Just get the adapter and fill your own off that.

A scuba fill is the same as a small fill. $5-$6. You just need the tank and fill station.

Aluminum SCUBA tank - excellent shape! $65 in Woodstock

Seems like a decent deal. No idea on what fill a station adapter is worth. If you're interested, we might be able to work something out.

Takes about 45 minutes with a 100 psi input to go from 1000 psi to around 4000 psi. So, an empty to full 4500 psi fill should take about an hour. 85 psi minimum input. They usually go for around $400 to $450 used.

How much power do you Think you burn running a shop compressor for 45mins?
PS. Real question, not trolling. I would like to know the net cost of an HPA system and this is the big part I think.

1/3 hp motor takes 475 watts

Blended electricity rates are 7.74 cents/kWh currently.

To fill a 68ci tank will tank will take anywhere from 1 to 4hrs.

An 80cu ft 3000 psi scuba tank will likely take 24 hrs.

High end on the power taken for all calcs using this electricity calculator.

ASSUMPTION:
The shoebox compressor requires a shop compressor to feed it. First compressor I found on Canadian Tire that output above 80psi was 1 1/3hp. The previous chart lists a 1.5hp motor at 1700 watts. Feel free to chime in if you have a compressor that uses more/less electricity.

68ci 4500 psi tank at 4hrs = (shoebox electricity) + (shop compressor)
=$0.15 +$0.53
=$0.68 per tank

80cu ft 3000 psi tank at 24hrs = (shoebox electricity) + (shop compressor)
=$0.88 + $3.16
=$4.04

I think Neb says a Scuba fill is $6. If we hadn't already bought the scuba, it would have been worth it. Now, it's a bit of a toss up (in my opinion). We've already invested in the scuba ($266) so as long as we keep that it's probably our best bet.

Things to consider:
-4 people getting 2 fills is about our max. If more people want more hpa, we may need to explore other options
-tanks need a $50 hydro every 5 years
-how long we plan on playing

Basically, if we don't get any new people playing with hpa and we only play for 5 years, I think we're good. If any of those 2 conditions change, we may need to rethink things.

What's a tank of nitrogen cost from your CO2 source? It's all the same stuff.


EDIT:
Appliance wattage calculator:
http://www.citytrf.net/costs_calculator.htm

I don't recall the exact cost, but I remember that CO2 was cheaper then N2.
I will E-mail my sales Contact at Air Liquide and get a Quote for an N2 Tank for comparison.

Hey Hey

Since I have been having trouble with the big tank, I am debating getting rid of it.
As such I have been looking at the HPA option more closely.

Bit of change in your math jew, according to the shoebox site, the shop compressor does not run full time.
The say it only comes on a few times during the fill process. not sure what a few times is but it does make sense.
From what I can determine the input requirements are 2cf/per minute at 85psi.
So if you have a 20 gallon air tank topped up to 125 psi, it would take awhile for the Shoebox to drain the tank low enough for the compressor to kick back in.

Just out of curiosity, who would be interested in splitsy's?
If I go the HPA route, I am going to have to invest in the same equipment as neb (260) so I am almost half there anyway.

That is assuming we build a rig that charges Nebs scuba with the shoebox. we could also snag another 80cf scuba and build a cascade.
We could save on the second tank in that there would be no need for the Hydro-test.