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DaveMann
Lung Diver
Posts: 61
Joined: Mon Aug 15, 2016 11:12 am
First Name: Dave
Location: Fort Myers, Fla., USA

Home Cascade System

Sun Oct 23, 2016 10:13 am

I've thought recently that If I owned a boat and a compressor I'd never have to go to a dive shop again. A boat is highly unlikely and a compressor is only slightly behind the boat in the unlikely department. However, I do live in the area of one of the "old people getting ready to die" capitols of the state. Accordingly large oxygen tanks, I mean the ones that are about 5 feet tall, show up at one of my favorite auctions from time to time.

Here are my thoughts and questions.

If I had a number of these large O2 tanks what number of them would it take to fill six 72 ft steel tanks? Are there 3000+ psi versions of these tanks? I could just hoist the big tanks into the back of the pickup get them filled every so often and not have to deal with the LDS politics of old tanks vs new, aluminum vs steel, etc. This sounds good to me, but does my idea have merit considering I don't have a compressor?


Dave

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captain
Plank Owner
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Joined: Mon Jul 04, 2005 11:32 am
Location: LaPlace, LA

Re: Home Cascade System

Sun Oct 23, 2016 10:39 am

It's possible but where would you get them filled plus most of the large medical oxygen cylinders are rented not owned. You would have to deal with the same issues as dive tanks, hydros, VIP etc. if you try to get a dive shop to fill them and most would not want to fool with them.
Commercial breathing air cylinders are available, but you can not buy them you have to rent them from the supplier and pay a deposit on them. Frankly a portable compressor is the best option if you can find a good used unit.
Captain

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Bryan
Plank Owner
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Joined: Fri Jun 24, 2005 11:40 am
First Name: Bryan
Location: Wesley Chapel Florida
Contact: Website

Re: Home Cascade System

Sun Oct 23, 2016 11:42 am

captain wrote: Frankly a portable compressor is the best option if you can find a good used unit.
Scuba Board, Craigslist etc have crazy deals on good used compressors all the time. If I could justify it in my head I'd have a fleet of low volume portable compressors setting around just waiting to pump air. Hookup on most is really simple as you get a pigtail cord (with correct wire size and plugs) run it from your dryer plug to the garage and pump all the air one diver could need for a lifetime. Terry Stevens got a really small Cornelius compressor for a few hundred bucks and he's filling all he needs for his own use. Granted it takes and hour to fill a cylinder but he's got the time. Maintaining a compressor will cost you less per year than annual rental on one cascade bottle from a vendor. Thats assuming they will rent/lease one to an individual in a residential neighborhood.
Doing it right should include some common sense, not just blindly following specs and instructions. .Gary D, AWAP on SB

swimjim
Master Diver
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Joined: Thu Mar 23, 2006 12:28 am
First Name: Jim
Location: Belgium WI

Re: Home Cascade System

Sun Oct 23, 2016 6:04 pm

Roger Van Frank had a nice system for sale earlier in the year and had no takers so he took it off the market so to speak. A compressor with four cascade bottles if I remember right. It would be just the ticket for you if it's still around. Price was right too.

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DaveMann
Lung Diver
Posts: 61
Joined: Mon Aug 15, 2016 11:12 am
First Name: Dave
Location: Fort Myers, Fla., USA

Re: Home Cascade System

Sun Oct 23, 2016 6:28 pm

Is that the one built into the trailer?

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Robohips77
Master Diver
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Joined: Mon Jul 17, 2006 5:26 pm
Location: Southwest in the Buckeye State

Re: Home Cascade System

Fri Nov 04, 2016 2:37 pm

DaveMann wrote:Is that the one built into the trailer?
Yes its the one. It wont be sale again until next April. The cascade bottles can pumped to 2500 and the compressor can top off any tank to approximately 3300-3500. The compressor being sold with the trailer is a 3.5 CFM mako. Will fill the four cylinders in about 7 hours from empty or absolute 0 psi. If you are interested pm me for details and price. I would be willing to take payments over the winter. :) I am taking it to Florida for an event in March. If you live in Florida we could meet and you could take it home. The four bottles were hydro tested this past year (june?). they will not need a hydro for a few years.
First dives? 1967 and I never lost the fever.

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SurfLung
Master Diver
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Joined: Sat Jan 01, 2011 2:03 pm
First Name: Eben
Location: Alexandria, MN
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Re: Home Cascade System

Wed Dec 21, 2016 12:40 pm

I did a lot of Cascade filling of my low pressure Twin 38s before I upgraded to a compressor. I did it (and STILL do it) because I wanted to dive the same set of tanks several times at the same dive location. If you're still interested in a cascade system, here's what I learned about cascade filling:

1. If you are filling low pressure tanks (like my 1800 psi Twin 38s), standard 3000 psi aluminum 80s are perfectly sufficient for cascade filling. They are cheap to buy (Joe Diver sells them for $125 ea), you can handle loading them in and out of the car to refill them at the dive shop, and they're commonly accepted for visuals and hydros at all dive shops.

2. When cascade filling, you get the best bang for your buck when filling EMPTY tanks. This goes against conventional recommendations to leave a 500 psi safety margin. But remember cascade filling is simply balancing from high pressure to low. So, if your cascade tank only has 500 psi left and the tank you want to fill already has 500 psi... you can't put any more into it. Also, if your typical dive only uses half a tank, then don't waste your cascade pressure filling all the way to full pressure. Fill it a little over half so that you'll be near empty when you finish your dive.

3. Use good judgment on the empty tank thing. For example, I dive mostly in shallow water lakes, 15-30 feet deep. Running out of air while diving in these conditions isn't such a big deal... Especially when you know its coming. In fact, I think its good to know what running out of air feels like. I use my watch or banjo gauge to time the approximate air time to arrive close to the dock when empty. I pull the J-Rod when I'm out and use the reserve to finish the dive close to empty.

4. A few of us used cascade filling at the Sea Hunt Forever show in Silver Springs Florida last year. We dove the show in 30 minute shifts and my Twin 38s lasted almost exactly right for two shifts including a pull on the reserve rod. I made of total of 9 dives over the weekend, refilling via cascade from only 5 scuba tanks: Two 72s at 2500 psi, two 80s at 3000 psi, and one HP80 at 3300 psi. The 9th dive I only had enough cascade capacity to fill my 38s to 1500 psi... But that was plenty enough to last for the final 30 minute shift!

DIY Gauge Conversion for my Cascade Hose.
- I replaced the original brass yoke and bleeder valve with the body and gauge from one of my vintage USD Tank Checker gauges. Sometimes these tank checkers can be had for a bargain price (this one was $16).
Image
- I used to use a tank equalizer hose with a banjo pressure gauge to cascade fill some of my vintage scuba tanks. I got to looking at the connections on the "T" and those on the tank checker and got the idea to try this little re-configuration. Getting the checker gauge apart was the hardest part. I had to cut some of the rubber overmold off the flats of the gauge connection to get a wrench to mate reliably. But otherwise, it went together slick as a whistle and it works perfectly for cascade filling.
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

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Robohips77
Master Diver
Posts: 738
Joined: Mon Jul 17, 2006 5:26 pm
Location: Southwest in the Buckeye State

Re: Home Cascade System

Wed Dec 21, 2016 3:37 pm

Compressor Sold. Trailer and cascade still available.
Robohips77 wrote:
DaveMann wrote:Is that the one built into the trailer?
Yes its the one. It wont be sale again until next April. The cascade bottles can pumped to 2500 and the compressor can top off any tank to approximately 3300-3500. The compressor being sold with the trailer is a 3.5 CFM mako. Will fill the four cylinders in about 7 hours from empty or absolute 0 psi. If you are interested pm me for details and price. I would be willing to take payments over the winter. :) I am taking it to Florida for an event in March. If you live in Florida we could meet and you could take it home. The four bottles were hydro tested this past year (june?). they will not need a hydro for a few years.
First dives? 1967 and I never lost the fever.

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SurfLung
Master Diver
Posts: 1462
Joined: Sat Jan 01, 2011 2:03 pm
First Name: Eben
Location: Alexandria, MN
Contact: Website

Re: Home Cascade System

Fri Feb 22, 2019 12:14 pm

Cascading at Sea Hunt Forever...
- Since I'll be diving my same set of Twin 38s five times a day at Sea Hunt Forever, I am setting up to cascade fill them. That's 10 half our dives at 30 feet depth. How do I get the most bang out of my 5 cascade filling tanks? Here's my method.
- Remember, cascade filling is really just equalizing a high pressure tank with a low pressure tank. If you try to fill a tank that already has 1000 psi from a cascade tank that has 1200 psi... You won't get much of a fill because the two tanks are almost already balanced. The greater the difference between cascade tank and fill tank, the better the fill you will get.
- In other words, the most efficient cascade fill would be to fill an EMPTY tank. So, breathe down your tanks as much as possible for best cascade efficency.
- At Sea Hunt Forever, my plan is to start with a 10% over fill on my 1800 psi Twin 38s... That will be 2000psi. When the first half hour is done, I'll check the pressure and see how much I used. If its over half, I'll cascade it back up to whatever amount I used. Then on the next dive I'll breathe it down pretty close to empty (0 psi). This time for the cascade fill, I'll start with my lowest pressure cascade tank and refill the 38s to just enough pressure for one 30 minute dive.
- Last time at Sea Hunt Forever, I actually just used the same set of 38s for two 30 minute dives without refilling in between. Usually I got down to the reserve on the second dive, pulled it, and finished the dive with just about 0 psi remaining pressure. That was easier than checking in between. BUT, in order to get two dives on one fill, I'd have to fill all the way up to 2000 psi... Which uses up my cascade capacity. Filling up to 1200 psi for each dive will make better use of my cascade tanks capacity.
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

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