Which dive compressor?

[Jammer]

Originally Posted by Idaho

Today I put the Rix Sweet Air oil-less compressor on the boat.

Good for you.


Readers should be aware that the Rix SA-6 was discontinued five years ago. While used compressors do come on the market, condition is of vital importance. The oil-less design has a shorter life than traditional compressors, and rebuilds can be prohibitively costly.

[Ballsnall]

Originally Posted by Jammer

Help me out here. How are you going to make O2 and Helium aboard? Also, do you have a good recipe for making sorb out of flour and baking soda? Asking for a friend.

Well yes, you will need to carry an o² cylinder and decant, not sure why you want the helium but just carry a cylinder and decant that as well if your up for 300' regularly.

Tell you friend it was just a suggestion, we have options now so no need to get bent over a suggestion.

[Sojourner]

Just throwing a name out there i hadn't heard of until a good, very smart, friend turned me onto them. L&W out of Germany. They have a full range of compressors, from huge down to what I got, the Eco100 which is a personal compressor I keep in and run from one of my lazarettes to fill our 3 bottles. German quality and attention to detail, easy to use, and quite a bit cheaper than Bauer, tho the quality seems about the same. Have a look:

https://lw-compressors.com/en/node/69

[clownfishsydney]

My Bauer Junior II petrol engine was on my catamaran for the two six month periods we sailed to Queensland. As someone else said, the start up draw via electricity means even a 5kW gen set will not start the electric motor one.

[Ballsnall]

Originally Posted by Sojourner

Just throwing a name out there i hadn't heard of until a good, very smart, friend turned me onto them. L&W out of Germany.
https://lw-compressors.com/en/node/69

Nice looking compressors, hard to beat German quality. Bauer have been the industry leader for many decades now although as you know they are aan expensive option, but you can find a certified service tech in just about every port worldwide so great parts availablity.

[Jammer]

Originally Posted by Sojourner

Just throwing a name out there i hadn't heard of until a good, very smart, friend turned me onto them. L&W out of Germany. They have a full range of compressors, from huge down to what I got, the Eco100 which is a personal compressor I keep in and run from one of my lazarettes to fill our 3 bottles. German quality and attention to detail, easy to use, and quite a bit cheaper than Bauer, tho the quality seems about the same. Have a look:

https://lw-compressors.com/en/node/69

They're good. Dive Gear Express resold their machines for a short time then stopped. I wouldn't know where to buy one now.

[neworleansrich]

After lots of consideration I decided to go with a portable, gasoline powered unit.

I had a Max-Air 35 which is like a Coltri. It was powered by a Honda 5hp. I now have a Baurer powered by a Harbor Freight Preditor 3.5hp. Both are good units. The Baurer is quieter and seems to run more efficiently. The Honda ran at 3500rpm and the Preditor runs at 1800rpm. Both take about 20min to fill a 80cf tank to 3000psi.

A permanent below deck install would be nice, but I don't really have the room in the ERs or Lazerettes. The gas engine decision was due to the fact that my generator is set up for 120v only. Even if I had 220v available I would need to keep the wires run very short since these compressors use a lot of power. Also, the electrically powered units are not that much quieter.

For an electric motor, pretty much everyone says you will need 220v. However, I have heard Browie has a new variable speed induction motor set up that runs on 120v.

Below deck, or engine room installs need to consider the heat these units generate, not insignificant. Also the noise and plumbing of the intake breathing air is real issue.

PM me for more info

[Idaho]

Originally Posted by Jammer

Good for you.


Readers should be aware that the Rix SA-6 was discontinued five years ago. While used compressors do come on the market, condition is of vital importance. The oil-less design has a shorter life than traditional compressors, and rebuilds can be prohibitively costly.

True, but misleading to some extent.

"With regard to spare parts for the American market:
For the SA Series Rix Industies USA will provide spare parts up to and until 31st Dec 2022
For the Microboost (Direct Drive) Rix Industries will provide spare parts up to and until 31st Dec 2021

Thereafter HSM will take responsibility to provide spares"


Thus, the Rix SA-6 is still a useful, serviceable compressor.

I have an extensive service & repair kit of parts onboard, and plan to only fill tanks to 2,200 psi, not 3,000+. That significantly extends the life of the replaceable parts, with the trade-off of shallower or shorter dives.

However, you do you. Cheers!

[hezi973]

Wow, lots of info to process so here few fact and questions. My boat is on order new and will go through an extensive post production refit. I want to plan every thing right before realizing all the "I wish I thought about it before". I am planning on heaving Integrel (motor tied generators), lots of solar (min 2000 W) and massive lithium bank so I suspect I will not be short on power. No gasoline (short of dinghy), no cooking gas on my boat for safety and less PITA factors. I am sticking with electric compressor. I do have a front Lazarette I am hoping to utilize the space for the compressor. I am getting the boat in France, sailing back to the US, will spend 1-2 years up he Hudson river north of NYC before going out full time cruising with my wife, daughter, and maybe grandma. I hope to circumnavigate.

Last time I scuba was 25 years ago in Thailand while getting my PADI. Thinking ahead I know I will go back and get recertified. living on the water, I want to take advantage of everything I can when it comes to water recreation sport, activities, etc. Obviously, I have a lot to learn. Thank you for the scubaboard.com I am sure I can get lots of info there on the equipment I will need to have. Here come the questions:

I never saw a cruiser with scuba equipment and steel cage for fill up. Is that something I need to concern myself with?

I don't have any scuba equipment and I am interested in getting the safest proven type. 4000 psi or 3000 psi? steel or aluminum? Fill to a lower PSI for safety or longevity? I never considered those factors... but I know I will get my tanks (and any safety related equipment) new and not used and to the safest standards. If anyone can give me a quick reply or send a link where I can educate myself in this matter I will greatly appreciate it!

Also, is it safe to leave a compressed tank on the boat indefinitely or I should bleed it out if I am not planning on using it for safety and longetivity? I am thinking if I need to go under fast in case of an emergency, I am not expecting to sit for 30 minutes waiting on a tank to be filled up. Sorry I know it may sound rudimentary buy I have no experience.

In regard to plumbing of air intake; what do I need to take into consideration? I was thinking the compressor draw air from the ambient surrounding it is in. Didn't think I need to bring air from a remote location. Is that due to the heat generated in the space it is at while under load?

Thank you!

[skipmac]

Originally Posted by hezi973

Wow, lots of info to process so here few fact and questions. My boat is on order new and will go through an extensive post production refit. I want to plan every thing right before realizing all the "I wish I thought about it before". I am planning on heaving Integrel (motor tied generators), lots of solar (min 2000 W) and massive lithium bank so I suspect I will not be short on power. No gasoline (short of dinghy), no cooking gas on my boat for safety and less PITA factors. I am sticking with electric compressor. I do have a front Lazarette I am hoping to utilize the space for the compressor. I am getting the boat in France, sailing back to the US, will spend 1-2 years up he Hudson river north of NYC before going out full time cruising with my wife, daughter, and maybe grandma. I hope to circumnavigate.

Last time I scuba was 25 years ago in Thailand while getting my PADI. Thinking ahead I know I will go back and get recertified. living on the water, I want to take advantage of everything I can when it comes to water recreation sport, activities, etc. Obviously, I have a lot to learn. Thank you for the scubaboard.com I am sure I can get lots of info there on the equipment I will need to have. Here come the questions:

I never saw a cruiser with scuba equipment and steel cage for fill up. Is that something I need to concern myself with?

I don't have any scuba equipment and I am interested in getting the safest proven type. 4000 psi or 3000 psi? steel or aluminum? Fill to a lower PSI for safety or longevity? I never considered those factors... but I know I will get my tanks (and any safety related equipment) new and not used and to the safest standards. If anyone can give me a quick reply or send a link where I can educate myself in this matter I will greatly appreciate it!

Also, is it safe to leave a compressed tank on the boat indefinitely or I should bleed it out if I am not planning on using it for safety and longetivity? I am thinking if I need to go under fast in case of an emergency, I am not expecting to sit for 30 minutes waiting on a tank to be filled up. Sorry I know it may sound rudimentary buy I have no experience.

In regard to plumbing of air intake; what do I need to take into consideration? I was thinking the compressor draw air from the ambient surrounding it is in. Didn't think I need to bring air from a remote location. Is that due to the heat generated in the space it is at while under load?

Thank you!

Which tank? For all around diving the Aluminum 80 cu ft (11 Liter) tank is the standard of the industry and in my opinion the best option. Several manufacturers. If I recall correctly the best are Luxfer as they are closest to neutral buoyancy IE when full they are slightly negative and when empty very slightly positive.

Regarding power and fills. Doesn't matter how much potential power you have, how many solar panels, etc. The big factor is how much instantaneous power you can put out to start the compressor. For electric there are two important specs, running load and startup load. Compressors are notorious for drawing a huge amount of power for a fraction of a second to get started. You will need to design your system to handle that. One option instead of a much larger, heavier and expensive generator is to add an inverter to the system that will add a temporary power boost to start the compressor while allowing use of a smaller generator.

[skipmac]

Originally Posted by Jammer

The problem with older aluminum cylinders is due to the use of 6351 alloy used by some manufacturers prior to 1988 when the industry switched to 6061 alloy. Most cylinders made from 6351 have been removed from SCUBA service.

There is no reason to believe that aluminum cylinders manufactured after 1988 are unsafe, as long as the five-year hydro tests and annual visual tests are performed..

That is my understanding, however, at least in Florida even the 6061 alloy tanks if older than some number of years that I don't recall, cannot be recertified.

Originally Posted by Jammer

It is not true that older steels are all failing although steel cylinders in a salt water environment will eventually corrode and fail, especially if they are not galvanized, especially in daily use. Again, the five-year hydro tests and annual visual tests are sufficient to identify failing cylinders and remove them from service before they become a hazard.

Agree. When I was doing a lot of tech diving I owned over 30 tanks, at least a dozen steel tanks, so I was at the local tank hydro shop at least once a year getting tanks tested. The guy that ran the shop said he had never seen a steel tank fail except from rust. Metal fatigue like you can see in aluminum tanks was not a significant factor.

Originally Posted by Jammer

Cylinder explosions resulting in loss of life are, tragically, common in countries that lack a safety culture and rule of law. Aside from the handful of fatalities from 6351 aluminum alloy cylinders that occurred before the hazard of this alloy were understood, I am unaware of any explosions of air cylinders in SCUBA service in the USA or Canada since the introduction of annual visual inspections in the early 1970s, and I have read through dozens of accident reports and searched carefully to try to find reports of such events.


Explosions involving oxygen cylinders and nitrox mixtures richer than 40%, while rare, do take place as a result of contamination of cylinders and fill lines with grease and oil. There are more of these in healthcare than SCUBA due to the sheer numbers of oxygen cylinders in medical service. From what I have been able to find there are one or two fatalities of this sort every year.

I seem to recall a couple of tank explosions in Florida sometime around the late 1990s or early 2000s. One in the keys and one I think on the west coast.

Regarding O2 clean risks, there's a lot of talk and some shops really paranoid about it but I have heard of very, very few actual fires or explosions. As a friend once pointed out, if O2 was that dangerous then you would see welding shops blow up every week as they are notorious for poor cleaning protocols.

[Jammer]

Originally Posted by hezi973

I never saw a cruiser with scuba equipment and steel cage for fill up. Is that something I need to concern myself with?

I wouldn't. Containment fill stations (not cages so much as steel drawers usually) are common in fire departments but not for SCUBA use. I don't think I've ever been to a dive shop that used a containment fill station.

I don't have any scuba equipment and I am interested in getting the safest proven type. 4000 psi or 3000 psi? steel or aluminum? Fill to a lower PSI for safety or longevity? I never considered those factors... but I know I will get my tanks (and any safety related equipment) new and not used and to the safest standards.

There are approximately 70 scuba diving fatalities per year in the United States. Few of these have equipment problems of any kind as a primary cause; those equipment problems that do form a significant part of an accident chain are usually caused by a lack of maintenance, or mistakes made in performing maintenance, rather than an inherent defect in the equipment. You can do your own reading on the usual causes if interested, see either the A&I section at Scubaboard or the DAN accident reports, or we can discuss in another thread.


Of those accidents that are related to the tank and compressor in any way, the most common problem is contamination of the tank by water, water vapor, or carbon monoxide. In most cases these problems are caused by insufficient filter changes on the compressor or by a compressor that is overheating or being coaxed along past its reasonable end of life (usually in dive shops).


As such safety is more a matter of skill, technique, and judgment than equipment choices. I believe there are certain equipment configurations (BC and regulators) that are more safe and those are the configurations I use, but I don't see that as a big part of dive safety.

I have a fleet of approximately 20 cylinders (=tanks) of various sizes and configurations. All but one are steel, and all but one were purchased used. Fill pressures vary from 2475 PSI to 3500 PSI. The manufacturing dates vary widely between 1962 and 2018. I believe they are all equally safe. I dive with them. My kids dive with them. If I end up with a tank that is unsafe I scrap it (sometimes happens since I buy them on eBay and Craigslist without trying to inspect them first).

Generally, among cylinders (=tanks) available new in the USA, 3442 PSI, galvanized steel cylinders are the best available for most diving. They are somewhat more compact than aluminum cylinders, and have neutral to slightly negative buoyancy, requiring less lead on your weight belt. They cost more than aluminum cylinders. For most people 100 cf cylinders are ideal for general diving. Shorter, more slender people may benefit from smaller cylinders.

Modern, high-quality compressors designed for 3500+ PSI fills will last for thousands of hours when filling cylinders to 3500 PSI (or 3442 PSI or whatever). Some (mostly older) compressors were built with lower pressure fills in mind. Don't buy those.

Also, is it safe to leave a compressed tank on the boat indefinitely or I should bleed it

You can leave it indefinitely as long as it doesn't become corroded or damaged as would happen if it were left in the bilge for a period of years.

In regard to plumbing of air intake; what do I need to take into consideration? I was thinking the compressor draw air from the ambient surrounding it is in. Didn't think I need to bring air from a remote location. Is that due to the heat generated in the space it is at while under load?

Compressors generate an enormous amount of heat so the main concern is ventilation to get rid of the heat.

You want the air inlet to the compressor to be away from any possible sources of contamination, such as exhaust from any engines or cabin heaters etc.

You will need access, because you have to check the oil before starting the compressor, and you have to drain condensate several times and hour (unless you're getting automatic controls to do that which adds weight cost and possible failure modes), and replace the filter cartridges every 25-100 or so fills with most onboard setups.

[team karst]

I"m about to commission a 3HP Alkin electric on my 38 cat. A few tricks involved. 120/240V genset switching, a soft start, and continuous blended nitrox to 3800 psi are the big ones. only one of us has a breather. Note any kind of gas/diesel powered compressors are very loud, the compressor by itself is only "loud".

and a smaller thing: get a 20' long fill hose to allow the tanks to sit in the dink.
Also, extend the various stage drains with tubes long enough to stuff into a cockpit drain.

[Mark424]

Originally Posted by clownfishsydney

My Bauer Junior II petrol engine was on my catamaran for the two six month periods we sailed to Queensland. As someone else said, the start up draw via electricity means even a 5kW gen set will not start the electric motor one.

This guy shows how to power an electric Bauer Jr from his 3kw inverter running off batteries using a (relatively) inexpensive freq converter.

https://www.youtube.com/watch?v=VoKSq631JAc

[Jammer]

Originally Posted by skipmac

That is my understanding, however, at least in Florida even the 6061 alloy tanks if older than some number of years that I don't recall, cannot be recertified.

That isn't true.


What is true is that many Florida dive shops set arbitrary policies regarding the maximum age cylinder that they will fill or inspect. This is easy for their staff to check and enforce. Dive shops don't make money from air fills and don't care if they lose the business from established divers who are unlikely to purchase high-end gear or classes.

Regarding O2 clean risks, there's a lot of talk and some shops really paranoid about it but I have heard of very, very few actual fires or explosions. As a friend once pointed out, if O2 was that dangerous then you would see welding shops blow up every week as they are notorious for poor cleaning protocols.

The difference is that welding shops use steel cylinders and brass regulators.


Technical divers generally use aluminum cylinders for oxygen because they like the buoyancy and trim characteristics of AL40s better than any steel cylinder that is presently in production. Aluminum is more susceptible to oxygen fires than either steel or brass. Medical users also generally use aluminum cylinders, and until recently used aluminum regulators. Most newer medical oxygen regulators are brass lined.


I can think of two serious accidents involving aluminum oxygen cylinders for technical diving exploding. One destroyed a dive shop and killed at least one worker and the other blew up a diver's car. No doubt there are others. Medical users burn up a regulator with high drama every few years and there's the occasional cylinder explosion.