Home Brewing Nitrox

[Charlestondivin]

After several trips to my lds to get my mix correct I am giving more and more
consideration to filling my own.

I need some advice here. Another local dive store went out of business and is
selling their compressor/bank setup. It is a Eagle 5 cu compressor that he
bought used a couple years ago with 4 - 4500 psi cascade bottles,
2 fill whips, and all the stuff to make it run. 220v.

I can post pictures of the compressor later. He is asking $2500 for the whole setup.
Worth the cost? Would I come out better buying new?
Any advice or opinions from my spearing brethren is appreciated.

[richhermes]

Now that would be an awesome setup for the garage!!

[fernandezh]

Charleston,
I am sure that you already know all the ins and out of brewing your own NITROX proboly better than most LDS. But I want to emphasize to everybody out there that they should recieve the proper training before mixing their own gases or tanks on their own.

I am sure there are enough LDS operators here who will be able to answer your question concerning this setup.

Hector

[Stone]

Was the dive shop doing Partial Pressure fills? If yes, does a hyperfilter come with the compressor? Does the compressor have synthetic oil in it?

You might consider continuous blending (especially if you don't have a hyperfilter).

And if you haven't already read it, get The Oxyhacker's Companion from airspeedpress.com.

[Stone]

Do a search for relevant threads on scubaboard.com. Uncle Pug and Omar are very knowledgeable, and Vance Harlow "Oxyhacker" is also a contributor.

[Charlestondivin]

Ive been reading up on scubaboard. The shop that had the
compressor did not fill nitrox. Since we would be getting the
banks i was tenatively planning to use continuous blending
and bank 32. We have a copy of OHC. We are still in the
planning stages right now but the compressor is kind of a limited
Time deal.

Hector, rest assured I'm not going into anything half assed. Im
real partial to living! Thats one of the main reasons im doing this.
Thankfully i have my own o2 analyzer. The dive shops analyzer
(only had one) was off and they were putting out nitrox +5-8 %
Rich. Double checked my sensor with another shop and it was
dead on. The shop did Correct the Error upon discovery but it
did not leave me with a "Warm Fuzzy Feeling"

[fernandezh]

Originally posted by Charlestondivin
Hector, rest assured I'm not going into anything half assed. Im real partial to living! Thats one of the main reasons im doing this. Thankfully i have my own o2 analyzer. The dive shops analyzer (only had one) was off and they were putting out nitrox +5-8 % Rich. Double checked my sensor with another shop and it was dead on. The shop did Correct the Error upon discovery but it did not leave me with a "Warm Fuzzy Feeling"


Dude,
Like I said, I figured you knew what you were doing. The analyzer discreprency you found is scary.


Hector

[Stone]

Originally posted by Charlestondivin
Ive been reading up on scubaboard. The shop that had the
compressor did not fill nitrox. Since we would be getting the
banks i was tenatively planning to use continuous blending
and bank 32. We have a copy of OHC. We are still in the
planning stages right now but the compressor is kind of a limited
Time deal.
If I could get a bank of four 4500 psi tanks for a good price, I'd probably buy them, but for use in the future. Unless the compressor has an autodrain, magnetic switch, and a way to automatically turn off the O2, then you still have to baby-sit the fill process. For me, that means it is less effort to just fill the scuba tanks directly.

If you continuous blend, consider building a second O2 analyzer for the compressor output. Your mixes will be dead on (within the accuracy of the analyzer).

Are you going to fill emergency O2 tanks as well?

[Slay Ride]

Another big reason for getting this is our LDS are not open late on Saturdays (or any day for that matter) and we don't usually get back til dark. This way we can re-fill the tanks and go the next day. Could save each person $1200 in new tank purchases. Have been reading the OHC and feel confident we can put this together nicely. Definetly will make the fill stick. Friends can come over for a N and O party. Choose your mix.

Les

PS Keep the suggestions coming.

[Slay Ride]

Stone:

Yes we are planning on filling emergency O2 tanks. 40 cf ponies. Probably 50-65% O2. Any reason for us to be overly concerned?

Question:

Using the fill stick mixes the gases prior to pressurization, correct? Does this mean that it is more efficient in O2 usage therefore able to use all the oxygen in the tank instead of only down to the needed PSI during partial pressure filling?

[Stone]

Originally posted by MegalodonMan
Another big reason for getting this is our LDS are not open late on Saturdays (or any day for that matter) and we don't usually get back til dark. This way we can re-fill the tanks and go the next day. Could save each person $1200 in new tank purchases. Have been reading the OHC and feel confident we can put this together nicely. Definetly will make the fill stick.

My wife and I ended up with 8 tanks for the very reason you stated. We still need 8 tanks, though, because we bought a boat and now do 4-tank dives during the summer.

I can pass on a couple of "lessons learned" on the Stik when you get ready to build it.

[Stone]

Originally posted by MegalodonMan
Stone:

Yes we are planning on filling emergency O2 tanks. 40 cf ponies. Probably 50-65% O2. Any reason for us to be overly concerned?

There is no concern if you are filling 100% O2, but filling 50-65% means you have to partial pressure (PP) fill. You should never run more than 40% through the compressor. If you PP fill, then you should hyperfilter the air out of the compressor (and that is another expense). I have some part numbers and prices for the stuff you need to build an O2 whip on my website. Some of Oxyhacker's part numbers are discontinued.

Question:

Using the fill stick mixes the gases prior to pressurization, correct? Does this mean that it is more efficient in O2 usage therefore able to use all the oxygen in the tank instead of only down to the needed PSI during partial pressure filling?

True statement. When my O2 analyzer on the output of the stik starts to drop, I turn off the O2 (what's left of it), turn off the compressor, and order a new tank of O2.

[Charlestondivin]

We will be filling usually
3 lp 108's 32%
3 lp 98's 32%
2 40 ponys 50%

Am i wrong in thinking that we could jam the banks with 32 then just fill from the banks without the compressor?
This compressor is overkill for our application but the price is right.

Stone I was hoping you would give us your input :) Thanks, it is appreciated !

I am sure you have probably seen this javascript Nitrox blending calculator
http://www.abovenbelow.com/nitroxcalc.htm
How handy is that!

[Spearchucker]

Rob - If you don't buy that compressor, then let me know.

John

[Stone]

Originally posted by Charlestondivin
We will be filling usually
3 lp 108's 32%
3 lp 98's 32%
2 40 ponys 50%

Am i wrong in thinking that we could jam the banks with 32 then just fill from the banks without the compressor?
This compressor is overkill for our application but the price is right.

Stone I was hoping you would give us your input :) Thanks, it is appreciated !

A cascade could be handy if you want to spend several hours up front filling it, then "fast" fill your scuba tanks later on. The amount of time filling the cascade or direct filling tanks is the same. If I fill 8 tanks directly, when I'm done, I'm done. If I fill a cascade, then I would have to turn around and start filling the scuba tanks from the bank.

Direct filling also means I can change the mix on the fly. Last weekend we dove four tanks with 35% and 2 with 32% (most of our sites are between 80 and 110 fsw).

Don't get me wrong, I'd like to have a bank, but IMO, the convenience doesn't come into play until I can turn on the compresser and let it run for 4 hours while I'm watching a "South Park" marathon. You must have an autodrain, magnetic switch, and O2 cutoff solenoid in order to let the compressor run unattended.

[Stone]

I've seen the Nitrox Calculators, but they are for PP blending. Continuous Blending is so much slicker.

I wrote a bunch of Nitrox utilities in Excel (that are also on my website). The one I use routinely lets me input the current mix and pressure in a used tank, and the final mix and pressure I want. It calculates the mix I need to add.

For example: if I have a tank with 32% and 800 psi, and I want 34% at 3000 psi, I have to set my mix for 34.7%. With an O2 analyzer on the compressor output, I can get that kind of accuracy (.1% is probably the best the analyzer can do anyway).

[Charlestondivin]

Awesome Stone. Gonna owe you a few brews after
we get done picking your brain here :)

My thought on filling the banks was that it would be easy to get
my consistant 32% o2 coming out of my compressor using cont
blend then jam the banks for the quick fills from empty.

I see what you are saying about filling on top of a mix. Being
that we would not do any pp filling your method makes sense to
save money on fills. Going to get your spreadsheets now.
Wouldn't this mean that you can only fill one tank at a time?
ie.. 1 tank has 1500 psi @ 32% other has 1k @ 33%
solution would be diff for each.

Seems odd that the dive shops around my area still do pp filling
when Cont blend seems so much safer, easier, and cost effective.

[Stone]

Originally posted by Charlestondivin
I see what you are saying about filling on top of a mix. Being
that we would not do any pp filling your method makes sense to
save money on fills. Going to get your spreadsheets now.
Wouldn't this mean that you can only fill one tank at a time?
ie.. 1 tank has 1500 psi @ 32% other has 1k @ 33%
solution would be diff for each.


Correct. I fill one tank at a time. Even if I added a second whip, it would not speed up the fill process. At 4.9 scfm, it takes 20 minutes to fill a completely empty AL80. If I add another whip, I still only get 4.9 scfm but I'm filling 160 cf.

[Charlestondivin]

Looked at the compressor this afternoon. It does have a autodrain. Not running synthetic oil, Looks like some of the guages on the front of the console are oil filled? It is actually 3 bottles cascaded instead of 4.
Looks to be in good working order but nameplate says it is Made in 1987. Still a deal?

[Stone]

Originally posted by Charlestondivin
Looked at the compressor this afternoon. It does have a autodrain. Not running synthetic oil, Looks like some of the guages on the front of the console are oil filled? It is actually 3 bottles cascaded instead of 4.
Looks to be in good working order but nameplate says it is Made in 1987. Still a deal?

Out of my league on evaluating a 16-year-old compressor.

Maybe some of the guys on scubaboard can help out.

The autodrain is a real plus, but you still have to turn off the O2 and prevent the motor from turning back on if there is a power failure (magnetic switch).

I spent about $5300 on a brand new compressor and all the other "stuff". Because my wife and I dive a lot, and we have a few friends that want us to fill their tanks, our return on investment is about 18 months (if I sold the fill station).

After that, we are saving about $1600 a year. The convenience is "Priceless".

[Slay Ride]

Stone:

My neighbor is a small engine mechanic and says no problem with rebuilding the whole thing if necessary. Are the oil filled gauges enough of an issue to replace them? In the engine it has regular oil versus synthetic. Any issues there? Bottles and hardware look in good condition. The hour meter says 781. Doesn't sound like that's a very high usage. Thanks for all the advise. We'd rather not jump, but I bet you are right about the convenience. Les

[gumshoe]

Les & Rob, You guys (and stone) are my hero's for setting this stuff up...my wife would kick my ass if I started to set this stuff up in the garage. Well, maybe it would be ok'd if we had a bigger garage...

Regardless, having read through this stuff, I thought I would copy a link of an interesting website with nitrox calculators for blenders.

For what it's worth - http://www.abovenbelow.com/nitroxcalc.htm

[Stone]

Originally posted by MegalodonMan
Stone:

My neighbor is a small engine mechanic and says no problem with rebuilding the whole thing if necessary. Are the oil filled gauges enough of an issue to replace them? In the engine it has regular oil versus synthetic. Any issues there? Bottles and hardware look in good condition. The hour meter says 781. Doesn't sound like that's a very high usage. Thanks for all the advise. We'd rather not jump, but I bet you are right about the convenience. Les

I'm not sure about the oil filled gauges. Oxyhacker says that some "oil" filled gauges are filled with glycerine (which is okay with O2), but some are filled with kerosene or mineral oil (ka-boom!). Even if you have to replace the gauges, you can get O2-clean gauges from a welding shop for about $15. You only need a $200 4-inch or digital gauge for PP filling.

I went with synthetic oil because I figure it's safer. The higher O2 content being compressed (assuming continuous blending) in the presence of hydrocarbon-based oil could produce CO.

The synthetic is more expensive, but it is apparently a better oil. The manual for my Bauer compressor say you only have to change synthetic oil half as often as regular oil (every 2000 hours).

My compressor is suppose to be good for 2000 hours between valve jobs (that's 8000 AL80s). If your compressor is similar, you're still a couple of years away from an overhaul.

Another thing about your compressor that is useful to know is its RPM. Mine is 3600, but I think they can get as low as 1100. Lower RPM will run cooler.

[Stone]

Originally posted by gumshoe
Les & Rob, You guys (and stone) are my hero's for setting this stuff up...my wife would kick my ass if I started to set this stuff up in the garage. Well, maybe it would be ok'd if we had a bigger garage...

Mine only takes up a 3x6 foot space (including 10 scuba tanks, the compressor, and the O2 bottle). I came up with most the space by tossing out some old metal shelves that were cluttered up with half empty paint cans and junk. Here's a picture: Nitrox Station. (http://www.magnificentrelief.com/nitrox.htm)

[gumshoe]

she would kick my ass if i spent any more money on scuba related ANYTHING right now.

sweet setup, by the way.

[Stone]

Originally posted by gumshoe
she would kick my ass if i spent any more money on scuba related ANYTHING right now.

She'll try to get me to stop at the jetties after a whole day of diving the Gulf for "just one more".

At the end of the dive day she says "that's $64". . . meaning that's $64 we didn't pay for 8 tanks of Nitrox.

When I told her the breakeven point on buying a compressor was about 18 months, and would save us at least $1600 a year, she said "go for it".

[Charlestondivin]

wow, fills here are from 10-14 per tank. Bit more Expensive.

[Stone]

Originally posted by Charlestondivin
wow, fills here are from 10-14 per tank. Bit more Expensive.

You'll break faster, then.

We can get $8 fills by buying a 10 or 20 fill card up front. A walk-in pays $10.

[fishhunta]

ive got it better than all of ya'll- i keep a one day a weeek job at a dive shop. that equals a key to the shop, free air, and nitrox for less than you pay for air.
diving around 550 dives a year, I think that job is worth it......

[Stone]

Originally posted by fishhunta
ive got it better than all of ya'll- i keep a one day a weeek job at a dive shop. that equals a key to the shop, free air, and nitrox for less than you pay for air.
diving around 550 dives a year, I think that job is worth it......

Too bad you didn't get the key to the liquor cabinet as well!

[Rob Holman]

We have it pretty good here in Seattle. With a little hunting you can get a nitrox fill for about 5.50 per tank.

I partnered with a dive buddy and we set up a cascade of 5 Helium and 3 O2 bottles. We have a nitrox fill down to about $1.50, and a trimix fill of 21/35 or 30/30 to about $10 bucks a tank. Compared to the 20-30 bucks a fill per tank (we dive twins often so that doubles it) at the dive shops, that is a deal on trimix.

We do not have a compressor, so we just take them to a dive shop to be topped off with O2 clean air. This works well since we can just fill the tanks with O2/HE at night and take them into a shop for a fill the next day. No waiting on the dive shop to put in O2, we can get whatever mix we want, and we never have to worry about showing up to the dive shop to find out they are out of O2. We can also top off our tanks and not waste the O2/HE. Many dive shops just drain the tanks before filling them. That makes the price go down even more-especially with trimix.

[swimndive]

Rob,
Cascades are a great for home brewing nitrox and low He2% tri-mix, but if you want anything higher than 35% you should consider getting a booster or a compressor or both. I used to go through 9 bottles of He and 3 of O2 for a weekend of cave diving. After a back to back weekend the garage would have 15 or so partially filled He2 bottles plus 5 O2 bottles, all paying my supplier rent. By getting a compressor and banking continuos blend tri mix I’m able to completely scavenge all of the supply bottles before returning them, so my rental fees have dropped by about 75%. ed

[Rob Holman]

My buddy and I thought about that and might do it. He made a booster for argon, it works pretty well. it is powered by a scuba cylinder. Our cascade is supporting about 2.5 divers who dive 3 times a week each. We need to take in about 3 or 4 HE/O2 tanks a month to keep our cascade alive.

We may move to a booster, but it sounds like you are doing a lot more mixing than we do combined!

[IyaDiver]

Stone & Charleston,

I don't know if this helps but I want to share some info on BAUER compressors. I am blind on Nitrox mix but I have some decent experience with maintaining BAUER compressors.

I have a few groups of friends and since we dive locations far away from re-fill stations, we have our own compressors. All portable BAUERS with gasoline Honda powering them. In one group, I share with a few a BAUER Capitano, this is a 5 CFM compressor 1991. In another group I share a BAUER Mariner (260 pounds !! ), this is a 6.5 CFM compressor 1987. My another friend has himself a newer BAUER Mariner 7 CFM, 1995 model and a BAUER Junior at 3.5CFM, 1994.

The BAUER is the only compressor common in Indonesia, in fact the entire Asia.

Of all the BAUER,only the small Junior at 3.5CFM operates at higher RPM, I forgot how high, I think it is about 2,100 RPM or something. The rest of the BAUERS I mentioned run at 1,300 RPM.
Since the ambient temperature of my country is very hot, we tends to work the compressor more because sometime we fill in direct sunlight on a boat cockpit.

The use of synthetic oil is an added bonus because it is able to withstand higher ambient temperature and supposedly lower carbon build up on the valves. However BAUER strongly warned that switching to synthetic oil from mineral oil need a few specials step, found in the manual. (Synthetic to mineral switching is OK ) You must replace the valves and a few more important things to do in order to prevent DAMAGE to the compressor.

Technicaly a BAUER compressor can survive more than 10,000 hours if well maintained. The valve change at 2,000 hours as reccomended by BAUER is not applicable in my hot country, 1.000 hours for the valve job is good enough.

If you guys pump up to 3,500 psi ( Euro DIN Valve ) the manual mentioned that the BAUER filter housing (gold anodized aluminum color ) can survive only 10,000 tanks of use ( something like that ), if you operate at 3,000 psi, it should survive as long as the compressor. Filter housing service life is based on cyle of one filled up and once cyle of emptying. That sudden emptying and filling up of the filter housing really work the aluminum body up.
We must think of the filter housing like scuba cylinder too. The new BAUERs have a special fill valve that allows only the filling hose to be emptied when switching tanks, this is good because we don't cycle the filter housing. The old model filling valve empties the filter housing ( up to its regulator setting presure ). It waste good air and cycles the filter housing up. This new designed fill valve is a very important design feature and every compressor should have one.

Any compressor that is operated by design at lower RPM, say a 1,300 RPM like the BAUERs I mentioned, should yield a longer service life.

If that Eagle 5 compresor is already at 781 hours, that is not much of use and in fact if it is from a dive shop and a 1987 unit, it sounds very low. I do not know the output of Eagle 5 but if we calculate based on a regular 80CubicFeet aluminum tank at total empty and the Eagle 5 is a 6 Cubic Feet per Minute (CFM) compressor. That means it has filled up only 3,500 tanks in its entire service life or say divided by 14 years of use that is equal to 251 tanks a year or 20 tanks per month. If it is a 10 CFM compressor ( this is BIG size !! ) , it has filled up only 5,857 tanks, or 35 tanks a month, for the entire 14 years of its life. Are you sure the compressor hours is that low ?

A compressor like BAUER is air cooled ( up to 10 CFM, the bigger one I don't know ) and it is a triple stage unit. The key in maintaining them is cool operating temperature, clean air intake filters and steady operating RPM.

I have over hauled a few compressors and have a long chat with the BAUER technical advisor for the Asia Pacific region these are my findings :

01. BAUER mentioned 125 fills as the average high pressure filter life. They did that test based in Europe typical 20-30% humidity. In places like Indonesia, Jakarta. We have about 80%+ humidity all year round, thus a 60 fills capability is good enough. The content of the high pressure filter housing is carbon and some other elements. If one keep using an already "saturated" high pressure filter cartidge, there will be some chemical reaction. There will be some sort of white dust ( oxidation ) produced by the overworked filter catridge. This dust resemble what we think like salt particle. I had come across a few compressor having that problem and I consulted with the BAUER Asia Pacific in Singapore.
This white dust will jam machine threads, final safety valves ( on top of filter housing ) and the regulator ( on the right lower side of the filter housing ). Cleaning wil help to some extend but changing the filter cartridge fast is the best solution. Many BAUER owners do not know that the small block on the right side of the BAUER filter housing is a regulator. This regulator works to keep the filter housing at a minimal of 2,000 psi before it allows the filling hose to flow the air. High pressure filtration is what they are after and this regulator is also like a one way valve. When the filling hose is empty of air for tank change or for compressor storage, there will be at least 2,000 psi of air in the filter housing. Save good air and prevent contamination from fouling the filter element. Just like a tank, keep some air in the filter housing. That white dust I mentioned will first attack the regulator internals. If you empty the filling hose (compresor off ) and your filter housing gets empty too, that means the regulator have leaked because of the white dust. I think US$ 200.00 is the cost of the regulator including the small block housing.


02. I just fix one of BAUER Mariner's second stage valves. This compressor is heavily used by a friend's dive shop. About 200-250 tanks a month of service. The exhaust and inlet valves (both steel ) were jammed up in the aluminum cylinder head. It seems the carbon from the compressor oil (mineral) have sooted so bad, it jammed the valves on the thread like a fine welding job. I think aside from switching to synthetic oil, a schedule to open up the valves for cleaning after 3 months (heavy use) is a good idea. It is one of those shit that happens and the manual never state that.

03. For those compressors used in a location close to sea water (shore ) and on board a boat, watch out for screws binding due to corossion. I have two BAUER that I often bring out to sea and they need heavy maintenance. In fact BAUER Asia told me in one of the technical seminar that 90% of the compressor they repair in Asia are corrossion related problem. BAUER uses aluminum cylinder heads and many other parts are aluminum to keep weight down. Anyone who knows what happens to aluminum and steel when matched together in salty environment will know they are prone to seize bad.

I don't do compressor repair commercially but since I own a few I maintain them and also help friends once in a while.

Hopefully my info is useful.


IYA

[swimndive]

Iya,
You bring up some very good points on Bauer compressors. Prospective compressor owners need to consider that places like Florida and Jakarta, are what Bauer considers to be an extreme operating environment (any place where it’s too warm to brew a good lager). All service intervals need to be cut in half as it states in their manual. For anybody considering getting a compressor around here I always recommend they splurge and get an auto condensate drain. In Fl, condensate should be drained every 10 mins (filters already only last half of their rated life), not doing so will further shorten filter life. Having operated a Mako portable in a marine environment over a decade ago, I can tell you, it’s no fun standing around a hot noisy compressor draining condensate while waiting for your tanks to fill. I now have a ’99 Mariner EV1with a P2 Securus system and ACD. It weighs around 700lbs with the cabinet, motor, gauges and filters. It uses a single-phase 7-1/2 hp motor to turn around 1250 rpm. I‘ve been running it with a 2300-cfm blower motor aimed at it’s heads, but it’s going to be moved into an air-conditioned building later this year. The carbon buildup problem you mentioned sounds like it might be oil related. When you switch to synthetic, don't use a diester based synthetic. Check this out http://www.dnax.com/new_nav/index1.html . Then check the rest of the food grade lubricant stuff out. No complaints or problems here with the ez-1000. I think my local shop is actually going to be switching over to it this weekend. He called last night to arrange a borrowed gallon for this morning.

Rob,
Yeah it takes a lot of gas because the supply bottles only come with about 2400psi of pressure, so most of it goes to waste. Now it all gets used. I can make any of the standard mixes I need by banking 18/35 and blending it with a pure gas or continuos blended top-off of some percentage directly from the compressor. There is a fellow up your way who uses his compressor to boost argon, but after giving it some serious thought I decide to just go with a booster. I’m going to install a bypass valve upstream of my filters and fill another set of banks with drive gas to give it an optimum supply. If you need any help calculating your needs I have a few aps that might help.

ed

[IyaDiver]

Thanks Ed,

That EZ-1000 should be a good alternative. When the filter get saturated it sure smell bad, I hope this one will smell like olive oil....:D :D

Do you know that the new Mariner 320 is pumping 11CFM (320 Liter / minute ). Portable !!!! Only 140kg / 308 lbs. This is a big jump over the regular Mariner (7CFM) and cost only 40% more, something like that. I think this is the most cost effective of all the Bauer. 7 minutes per 80CF tank, my my, what a speed !!!

Check

http://bauerasia.com/mariner.htm#mariner320


Regards,
IYA

[JaxShooter]

Hello there. If I can be of any assistance with buying or using a compressor system feel free to contact me. I have a store here in Florida. I have been through the training for filling and servicing O2 tanks. We have a hyper fill system for filling you can view this on our web site www.diverselitetraining.com Proper training is the key to safety, I can reffer you to a qualified instructor for any training needs. Thanks Wally

[100days-a-year]

Hi Wally,just figured out who you was.If you ever want to get into pumping mix or using boosters and Haskells gimme a ring.My buddy has been teaching tri-mix for over 10 yrs.He lives in OP and has the most kick-ass home fill station.Banked 4500,3500,3000 in air and banked mix.Over 8000cu ft in banks + He and 02

[JaxShooter]

Thanks Tony. Hope all is well. Let's get out and do some shooting together. Talk to you later.

Wally