Thinking about building my own...

lolwhat · 14th August 2006, 14:09

I've gotten a hankering for building my own CCR. It'd be similar to the TP-2000 [1], but with some differences.

First, some background:

I'm a typical rec OC diver. I've been down to 130fsw, with no intention at this point of venturing further. I've dived wet and dry, in warm and cold waters. I don't penetrate caves or wrecks to any serious extent - just a few caverns, and wrecks that are wide-open enough to be considered "cavern." I watch my gauges like a hawk, and I'm always alert for any strange noises emanating from my gear. I'm also neither electronically nor mechanically inclined to a strong degree - although I may exert more effort in these regards eventually - so I'm usually of a mind to buy a few things off the shelf and put them together in a way that minimizes welding, cutting and swearing.

My regular buddies are "WTF A REBREATHER WILL KILL YOU!" with some "OMG THEY'RE $$$" thrown in, so I'm not able to convince any of them (yet) to get one. Thus, my diving will be confined to no-deco-OC limits for the foreseeable future, as my buddy will almost invariably be on OC. Even if I get lucky and hook up with a CCR diver, I'll be staying no-deco.

So, as I mentioned earlier, I'll start off with a design like that of the TP-2000, then go from there. Hold your questions until the end, please.

I'll wear a typical BC used for OC. It's a Zeagle Ranger, if you must know, with an SS BP and weight integration.

My dil will be a standard-size tank (e.g. Al-80) worn on my back - same size tank as my buddy's, and same mix (air or EANx).

I'll attach a typical OC 1st stage to the tank. This will feed an SPG, an OC 2nd stage, and a gas switch block.

The 2nd stage will be on a long hose and tucked into the front of my rig somehow. It'll be bailout for either myself or my buddy.

The O2 tank will be either mounted on the scrubber, or clipped to the BC. It'll have an O2-clean 1st stage (of course), and it'll feed the block and a standard-size SPG. I'll try to set things up so that I can have the O2 SPG "next to" the dil SPG without draping the hose across my chest.

The block will be fed not only from the dil tank, but also from the O2 tank. In turn, the block will feed a valve on the loop. I'll be looking around RBW for a place from which to buy said block, but I'm welcome to opinions.

The valve will be either an O2-clean OC 2nd stage, or a more typical ADV found on, say, a KISS. I honestly don't know how well a 2nd stage would work, as opposed to a proper ADV; however, I already have a spare 2nd stage, while I don't have an ADV laying around. In any event, we'll call this part of the rig the "ADV" for the purposes of this conversation.

The counterlungs cum breathing hoses will be similar to those of the TP-2000 - motorcycle tire, or something of similar construction. The ADV will be parked on the exhale CL, as the manual inflator is on the TP. I'll have triple O2 sensors, right "under" the ADV, so that gas flow will keep the sensors reasonably dry.

The sensor/display setup will be off the shelf; I'm still weighing my options.

The DSV will be hopefully be the same as that on the D5 [2], if that type is still available; otherwise, it'll be the typical DSV style.

The scrubber will also be off the shelf - again, looking at the choices out there, especially ones that provide a decent water trap, like the TP-2000's rather innovative one. It'll probably be sidemounted if I get the DSV I want, or chestmounted if not.

OK, now to answer some of your questions:

You're feeding your O2 and dil through one valve? How do you know when to switch back and forth?

It'll be set to O2 on the surface. As I descend past 1.3ata (10fsw) or so, I'll switch to dil, and stay there unless my PO2 falls below, say, 1.0ata; I'll switch back and forth as necessary. When I hit my planned depth, I'll switch to O2. As long as I maintain my depth, the ADV will be replacing only the O2 that I've been consuming, so loop PO2 won't rise or fall considerably.

What if something goes bad?

If the block somehow doesn't allow any gas flow at all, I'll notice that the ADV isn't "firing," or I'll see the PO2 falling on my displays. If the block is somehow passing both O2 and dil, again, I'll notice the PO2 on my displays. If the rig springs a leak, my buddy or I will notice the bubbles. In any event, I'll try to isolate and minimize the problem, or bail out if necessary. Of course, as always, CO2 problems are difficult to foresee, so I'll just have to Do What Everyone Else Does.

Hold on. Your bailout is fed from the same 1st stage as the dil. If something goes wrong on that side of things, your bailout won't work either.

My buddy will hook me up.

You trust your buddy to be paying attention?

I trust my regular buddies, anyway. If I'm diving with someone else who turns out to be an idiot, I can always do an ESA. Since it'll be no-deco dive anyway, the worst that can happen is that I miss my safety stops and get a minor bend.

You haven't thought of x.

Great, tell me what x is.

[1] http://www.nwdesigns.com/rebreathers/TP2000/Default.htm
[2] http://www.sump4.com/rebreather/d5_construction.html

lizardland · 14th August 2006, 19:05

"X" = what you'll spend building/modifying a rebreather, time lost to test diving as opposed to real diving, going back and fixing/replacing, raw materials cost (buying one of anything is never enough as you'll either break it, change it or the supplier just won't sell in lots less than 5), etc., will come pretty close to buying a rebreather. Probably even come to more than buying one.

On my homebuilds I spent well in excess of what my KISS cost me in the end. For every hour of real diving I got on my homebuilds I've had about five hours on my KISS.

On the other hand it is very good learning building rebreathers. Usually homebuilders fall into two groups: builders who like to dive and divers who like to build. I fell into the latter and like most who do, buying a Rebreather was much less painful.

I'm not cynical about homebuilds but for me I just don't have the personality for it.

Cheers,

Stuart

lolwhat · 14th August 2006, 20:00

lizardland,

Thanks for your thoughts. I should've mentioned one reason for possibly building my own CCR - the time (and money) required to get training on whatever CCR I bought off the shelf.

The two rebreather instructors that I've heard of in town teach the Dolphin - nothing else. So, I'd probably have to travel to get instruction. Also, being in the U.S., I work for an employer that gives only ten days of vacation each year, and my vacation days are already committed to other things for at least the next year. Thus, even if I found an instructor who could travel here, I wouldn't be able to spend a solid week on CCR training until at least 2008.

I welcome other suggestions, but it's homebuild or bust for me at this point.

rdmmdr · 14th August 2006, 20:41

if you want a straight kiss type unit the best bet is to buy a used one when they con up you cant build it for the price unless you are going to build most of your own parts. if you have access to a lathe the scrubber is easy for a cost of about 50$ in parts. the dsv is the most expensive item around 800 to a 1000, use you old regs no cost there, the sensors can be done several ways but go redundant i figure that i have about 400 in a double redundant eccr system. including the solinoid and rechargable batteries. figure a couple of hundred in hoses. and if you use a lot of fittings plan on couple of hundred. about finished with mine a biopak 240 conversion and i figure that i have about 2200$ in it. and god knows how many hours figuring how to get it done.

rick

Ken · 14th August 2006, 22:07

Quote: (Originally Posted by lolwhat)

lizardland,

Thanks for your thoughts. I should've mentioned one reason for possibly building my own CCR - the time (and money) required to get training on whatever CCR I bought off the shelf.

The two rebreather instructors that I've heard of in town teach the Dolphin - nothing else. So, I'd probably have to travel to get instruction. Also, being in the U.S., I work for an employer that gives only ten days of vacation each year, and my vacation days are already committed to other things for at least the next year. Thus, even if I found an instructor who could travel here, I wouldn't be able to spend a solid week on CCR training until at least 2008.

I welcome other suggestions, but it's homebuild or bust for me at this point.

Some logic here. You have time committed to vacation. However, you d build and train yourself on an unknown/untested unit in lieu of getting training. My two cents would be to get a piece of kit that works, save development costs and find 5-6 days of wiggle room to train properly. I recently saw a KISS sport go for 2600.00 on ebay, in addition to used Classic Inspirations going for the 3K mark. My two cents as an instructor.

Crazyduck · 14th August 2006, 23:01

Happy tone here.. not negative.

If you are married or have kids I would at least take an introduction class or pay for KISS certification class and get some real time before starting this project. Give yourself some grounding.

A rebreather manufacture said to me “Andy you don’t know what you don’t know.” This implies to everyone without certification or education myself included. What you don't know- gets you into serious trouble.

Adding O2 through a demand valve is not the best idea. What if it jams open- you now have a free flow. You have not mentioned it but most people add a slide shut off valve in case this happens.
The real issue here is that most add valves can trickle…or leak gas when you breathe (static pressure pulls on them from inhaling.) Please be careful with this idea especially at depth.

The first stage intermediate pressure for O2 has to be changed…

Using a second stage without certain modifications will result in a free flow effect when sealed for an ADV.

The TP 2000 was manually driven… O2 was not added in this manner.

Sidemounting will provide a pressure differential for positioning and effect the ability of the diver to breathe- just a thought. Chest mount comes with other effects.

There have been situations where the divers have a serious problem and they do not want to come off the loop- for whatever reason and we don't know why. BOV is easier than you buddy trying to figure out what button to push at depth and trying to pull you out of a breathing or gas problem.

Just some things I noticed.
There are more- development is a process of trade offs.
I would suggest some reading before you do any more planning.

Careful as you go…

Regards, Andrew

narked at 90 · 15th August 2006, 00:28

i've done it all ways home builds and brought units make your own is a very good way to learn more than most that just buy off the shelf but it is not the cheap way to do things im selling my ccr dolphin now as im collecting to many so if your just wanting some thing at the right price them it's here!
£1000 all in..+PP full ccr with displays tanks ,custom back plate ,regs kiss valve all the bits and peices and the rest i cant think of now!
goes on ebay very soon
kind regards john routley

rdmmdr · 15th August 2006, 04:17

buy the kiss
rick

Drmike · 15th August 2006, 06:29

Quote: (Originally Posted by lolwhat)

. I should've mentioned one reason for possibly building my own CCR - the time (and money) required to get training on whatever CCR I bought off the shelf.

Just because you can build a rebreather doesnt automatically mean you have a clue how to safely dive it.

If you really are going to go down this route do your family a favour and at least find yourself ccr dive buddy/mentor who will show you the ropes and stop you from killing yourself.

nicka · 15th August 2006, 09:51

Good for you.
Im in a similar situation.
8 months of building,and still months away from any unit im happy with!
On plan number 4!
Learnt huge amounts ,but just a begineer<img>,and accept this happily.
Spent lots of cash on bits I didnt need,or shouldnt have bothered wasting my time with.Garage is full of hose,plastic,bcd bits,ppo2 handset prototypes,rubber seals, AND I LOVE IT <img>
JUst into learning as much as I can,
not trying to reinvent the wheel,but just build my own!
You have put some brain hours into your plan,sounds interesting but your o2/dil switch seems a bit risky?
"what if " always happens when you dont want it!
"rebreather" or "life support unit"
Which one sounds more critical?

14th August 2006, 14:09	#1 (permalink)
lolwhat New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jul 2006 Location: Midwest USA Posts: 28	Thinking about building my own... I've gotten a hankering for building my own CCR. It'd be similar to the TP-2000 [1], but with some differences. First, some background: I'm a typical rec OC diver. I've been down to 130fsw, with no intention at this point of venturing further. I've dived wet and dry, in warm and cold waters. I don't penetrate caves or wrecks to any serious extent - just a few caverns, and wrecks that are wide-open enough to be considered "cavern." I watch my gauges like a hawk, and I'm always alert for any strange noises emanating from my gear. I'm also neither electronically nor mechanically inclined to a strong degree - although I may exert more effort in these regards eventually - so I'm usually of a mind to buy a few things off the shelf and put them together in a way that minimizes welding, cutting and swearing. My regular buddies are "WTF A REBREATHER WILL KILL YOU!" with some "OMG THEY'RE $$$" thrown in, so I'm not able to convince any of them (yet) to get one. Thus, my diving will be confined to no-deco-OC limits for the foreseeable future, as my buddy will almost invariably be on OC. Even if I get lucky and hook up with a CCR diver, I'll be staying no-deco. So, as I mentioned earlier, I'll start off with a design like that of the TP-2000, then go from there. Hold your questions until the end, please. I'll wear a typical BC used for OC. It's a Zeagle Ranger, if you must know, with an SS BP and weight integration. My dil will be a standard-size tank (e.g. Al-80) worn on my back - same size tank as my buddy's, and same mix (air or EANx). I'll attach a typical OC 1st stage to the tank. This will feed an SPG, an OC 2nd stage, and a gas switch block. The 2nd stage will be on a long hose and tucked into the front of my rig somehow. It'll be bailout for either myself or my buddy. The O2 tank will be either mounted on the scrubber, or clipped to the BC. It'll have an O2-clean 1st stage (of course), and it'll feed the block and a standard-size SPG. I'll try to set things up so that I can have the O2 SPG "next to" the dil SPG without draping the hose across my chest. The block will be fed not only from the dil tank, but also from the O2 tank. In turn, the block will feed a valve on the loop. I'll be looking around RBW for a place from which to buy said block, but I'm welcome to opinions. The valve will be either an O2-clean OC 2nd stage, or a more typical ADV found on, say, a KISS. I honestly don't know how well a 2nd stage would work, as opposed to a proper ADV; however, I already have a spare 2nd stage, while I don't have an ADV laying around. In any event, we'll call this part of the rig the "ADV" for the purposes of this conversation. The counterlungs cum breathing hoses will be similar to those of the TP-2000 - motorcycle tire, or something of similar construction. The ADV will be parked on the exhale CL, as the manual inflator is on the TP. I'll have triple O2 sensors, right "under" the ADV, so that gas flow will keep the sensors reasonably dry. The sensor/display setup will be off the shelf; I'm still weighing my options. The DSV will be hopefully be the same as that on the D5 [2], if that type is still available; otherwise, it'll be the typical DSV style. The scrubber will also be off the shelf - again, looking at the choices out there, especially ones that provide a decent water trap, like the TP-2000's rather innovative one. It'll probably be sidemounted if I get the DSV I want, or chestmounted if not. OK, now to answer some of your questions: You're feeding your O2 and dil through one valve? How do you know when to switch back and forth? It'll be set to O2 on the surface. As I descend past 1.3ata (10fsw) or so, I'll switch to dil, and stay there unless my PO2 falls below, say, 1.0ata; I'll switch back and forth as necessary. When I hit my planned depth, I'll switch to O2. As long as I maintain my depth, the ADV will be replacing only the O2 that I've been consuming, so loop PO2 won't rise or fall considerably. What if something goes bad? If the block somehow doesn't allow any gas flow at all, I'll notice that the ADV isn't "firing," or I'll see the PO2 falling on my displays. If the block is somehow passing both O2 and dil, again, I'll notice the PO2 on my displays. If the rig springs a leak, my buddy or I will notice the bubbles. In any event, I'll try to isolate and minimize the problem, or bail out if necessary. Of course, as always, CO2 problems are difficult to foresee, so I'll just have to Do What Everyone Else Does. Hold on. Your bailout is fed from the same 1st stage as the dil. If something goes wrong on that side of things, your bailout won't work either. My buddy will hook me up. You trust your buddy to be paying attention? I trust my regular buddies, anyway. If I'm diving with someone else who turns out to be an idiot, I can always do an ESA. Since it'll be no-deco dive anyway, the worst that can happen is that I miss my safety stops and get a minor bend. You haven't thought of x. Great, tell me what x is. [1] http://www.nwdesigns.com/rebreathers/TP2000/Default.htm [2] http://www.sump4.com/rebreather/d5_construction.html
(Offline)

14th August 2006, 19:05	#2 (permalink)
lizardland Yak Current Rebreather/s: MK 15.X Home Build Other Rebreather/s: Classic Kiss Home Build Join Date: Mar 2005 Location: North... Posts: 1,387	Re: Thinking about building my own... "X" = what you'll spend building/modifying a rebreather, time lost to test diving as opposed to real diving, going back and fixing/replacing, raw materials cost (buying one of anything is never enough as you'll either break it, change it or the supplier just won't sell in lots less than 5), etc., will come pretty close to buying a rebreather. Probably even come to more than buying one. On my homebuilds I spent well in excess of what my KISS cost me in the end. For every hour of real diving I got on my homebuilds I've had about five hours on my KISS. On the other hand it is very good learning building rebreathers. Usually homebuilders fall into two groups: builders who like to dive and divers who like to build. I fell into the latter and like most who do, buying a Rebreather was much less painful. I'm not cynical about homebuilds but for me I just don't have the personality for it. Cheers, Stuart __________________ Can you imagine drifting along in the sea with your mouth open and a load of f***ing plankton going in? You'd like it, would you? www.westons-cider.co.uk Azerbaijani Association of Technical Divers Publicity Officer and Goat Wrangler
(Offline)

14th August 2006, 20:00	#3 (permalink)
lolwhat New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jul 2006 Location: Midwest USA Posts: 28	Re: Thinking about building my own... lizardland, Thanks for your thoughts. I should've mentioned one reason for possibly building my own CCR - the time (and money) required to get training on whatever CCR I bought off the shelf. The two rebreather instructors that I've heard of in town teach the Dolphin - nothing else. So, I'd probably have to travel to get instruction. Also, being in the U.S., I work for an employer that gives only ten days of vacation each year, and my vacation days are already committed to other things for at least the next year. Thus, even if I found an instructor who could travel here, I wouldn't be able to spend a solid week on CCR training until at least 2008. I welcome other suggestions, but it's homebuild or bust for me at this point.
(Offline)

14th August 2006, 20:41	#4 (permalink)
rdmmdr designer of death Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Mar 2006 Location: kerman,california Posts: 372	Re: Thinking about building my own... if you want a straight kiss type unit the best bet is to buy a used one when they con up you cant build it for the price unless you are going to build most of your own parts. if you have access to a lathe the scrubber is easy for a cost of about 50$ in parts. the dsv is the most expensive item around 800 to a 1000, use you old regs no cost there, the sensors can be done several ways but go redundant i figure that i have about 400 in a double redundant eccr system. including the solinoid and rechargable batteries. figure a couple of hundred in hoses. and if you use a lot of fittings plan on couple of hundred. about finished with mine a biopak 240 conversion and i figure that i have about 2200$ in it. and god knows how many hours figuring how to get it done. rick
(Offline)

14th August 2006, 22:07	#5 (permalink)
Ken Team Torrent Current Rebreather/s: Inspiration Classic Megalodon Classic Kiss Other CCR Other Rebreather/s: Other CCR Join Date: Mar 2005 Location: New York City Posts: 331	Re: Thinking about building my own... Quote: (Originally Posted by lolwhat) lizardland, Thanks for your thoughts. I should've mentioned one reason for possibly building my own CCR - the time (and money) required to get training on whatever CCR I bought off the shelf. The two rebreather instructors that I've heard of in town teach the Dolphin - nothing else. So, I'd probably have to travel to get instruction. Also, being in the U.S., I work for an employer that gives only ten days of vacation each year, and my vacation days are already committed to other things for at least the next year. Thus, even if I found an instructor who could travel here, I wouldn't be able to spend a solid week on CCR training until at least 2008. I welcome other suggestions, but it's homebuild or bust for me at this point. Some logic here. You have time committed to vacation. However, you d build and train yourself on an unknown/untested unit in lieu of getting training. My two cents would be to get a piece of kit that works, save development costs and find 5-6 days of wiggle room to train properly. I recently saw a KISS sport go for 2600.00 on ebay, in addition to used Classic Inspirations going for the 3K mark. My two cents as an instructor.
(Offline)

14th August 2006, 23:01	#6 (permalink)
Crazyduck Underwater Mechanic Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Mar 2005 Location: TEXAS, Dallas/ Ft.Worth Posts: 720	Re: Thinking about building my own... Happy tone here.. not negative. If you are married or have kids I would at least take an introduction class or pay for KISS certification class and get some real time before starting this project. Give yourself some grounding. A rebreather manufacture said to me “Andy you don’t know what you don’t know.” This implies to everyone without certification or education myself included. What you don't know- gets you into serious trouble. Adding O2 through a demand valve is not the best idea. What if it jams open- you now have a free flow. You have not mentioned it but most people add a slide shut off valve in case this happens. The real issue here is that most add valves can trickle…or leak gas when you breathe (static pressure pulls on them from inhaling.) Please be careful with this idea especially at depth. The first stage intermediate pressure for O2 has to be changed… Using a second stage without certain modifications will result in a free flow effect when sealed for an ADV. The TP 2000 was manually driven… O2 was not added in this manner. Sidemounting will provide a pressure differential for positioning and effect the ability of the diver to breathe- just a thought. Chest mount comes with other effects. There have been situations where the divers have a serious problem and they do not want to come off the loop- for whatever reason and we don't know why. BOV is easier than you buddy trying to figure out what button to push at depth and trying to pull you out of a breathing or gas problem. Just some things I noticed. There are more- development is a process of trade offs. I would suggest some reading before you do any more planning. Careful as you go… Regards, Andrew __________________ Howdy Senor- What’s Happening! Rob Davie April 2005- Presently in a state of transition from Open Circuit to Closed Circuit. "You will not be punished for your anger; you will be punished by it." - Buddha.
(Online)

15th August 2006, 00:28	#7 (permalink)
narked at 90 John Routley Current Rebreather/s: Inspiration Classic Other CCR Dolphin Home Build Other Rebreather/s: Other CCR Dolphin Home Build Join Date: Feb 2005 Location: middlands uk Posts: 1,074	Re: Thinking about building my own... i've done it all ways home builds and brought units make your own is a very good way to learn more than most that just buy off the shelf but it is not the cheap way to do things im selling my ccr dolphin now as im collecting to many so if your just wanting some thing at the right price them it's here! £1000 all in..+PP full ccr with displays tanks ,custom back plate ,regs kiss valve all the bits and peices and the rest i cant think of now! goes on ebay very soon kind regards john routley __________________ *WWW.NARKEDAT90.CO.UK* *http://www.grpservices.com/pursuit/* Supporting Shearwater Research Products in Europe Narked at 90 Go Military
(Offline)

15th August 2006, 04:17	#8 (permalink)
rdmmdr designer of death Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Mar 2006 Location: kerman,california Posts: 372	Re: Thinking about building my own... buy the kiss rick
(Offline)

15th August 2006, 06:29	#9 (permalink)
Drmike RBW Member Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,378	Re: Thinking about building my own... Quote: (Originally Posted by lolwhat) . I should've mentioned one reason for possibly building my own CCR - the time (and money) required to get training on whatever CCR I bought off the shelf. Just because you can build a rebreather doesnt automatically mean you have a clue how to safely dive it. If you really are going to go down this route do your family a favour and at least find yourself ccr dive buddy/mentor who will show you the ropes and stop you from killing yourself. __________________ Cave diving is a sport Wreck diving is a sport Diving in general is a sport 'Rebreather diving' is not a sport its the delusional obsession with a highly dangerous and often inappropriate piece of equipment
(Offline)

15th August 2006, 09:51	#10 (permalink)
nicka New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Apr 2006 Location: new zealand Posts: 24	Re: Thinking about building my own... Good for you. Im in a similar situation. 8 months of building,and still months away from any unit im happy with! On plan number 4! Learnt huge amounts ,but just a begineer<img>,and accept this happily. Spent lots of cash on bits I didnt need,or shouldnt have bothered wasting my time with.Garage is full of hose,plastic,bcd bits,ppo2 handset prototypes,rubber seals, AND I LOVE IT <img> JUst into learning as much as I can, not trying to reinvent the wheel,but just build my own! You have put some brain hours into your plan,sounds interesting but your o2/dil switch seems a bit risky? "what if " always happens when you dont want it! "rebreather" or "life support unit" Which one sounds more critical?
(Offline)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode