Homebuilt Meg Radial Scrubber

bajaecotours

Thanks for sharing your shop skills and drawings. I will definately take your informaiton to proceed with making a few canisters.

Of note....you mentioned you are getting only 3 hours on the standard scrub canister. I have gotten many more hours on my standard can.

Here are my basic dive profiles and times:
Dive 1: 120mins to 1:50min @ max depth of 90ft
Dive 2: 120mins to 1:50min @ max depth of 70ft

*Day out of the water and scrubber canister in rebreather or large ziplock bag*

Dive 3: 120mins @ max depth of 50ft
Dive 4: 120mins @ max depth of 50ft

Dive conditions and workload info:

Water temps around 85-89f and not a heavy work load while filming.
With these conditions I have easily gotten 8hours or more on my standard canister over repeated dives. I have not gone beyond this point....However I think with one of my dive buddies we'll try for another hour and see if conditions remain the same. We have had absolutely no side affects of Hypercapnia at this point are are always EXTREMELY AWARE for these side affects to occur.

***for what it's worth-----

Would like to know what duration you expect out of your larger canister?

Again thanks for the information and well done.
Johnny

Skipbreather

Hi Johnny-

Glad you liked the write up & hope your version works well for you.

I have no doubt you got the times you did from your axial given the innocuous conditions of the dives. Pushing stated scrubber times seems to be common w/ many warm water Rebreather divers. Keep in mind I was quoting ISC’s *rated* burn time of the axial. That means they did some pretty thorough testing & doubtless chucked in a safety factor, then posted a time that would work in the worst of conditions.

My diving runs to the moderately deep (50-80 m) very cold (4 deg C) high workload (multiple stages & heavy exposure suit w/ thermal undergarments) variety of deep cold wrecks. It is a very, very different set of conditions from yours. I tend to hedge my bets by observing the manufacturer’s guidelines for his scrubber; that way I know there’s something left if I get snagged in a wreck, go WAY over run time getting free, and get slammed w/ an hour or two’s extra deco. I might freeze my ass off doing the hang time, but I won’t get bent. That’s also why I noted that right now I’m limiting my planned burn times on my design to 6~61/2~7 hours. I’m very confident it will go longer but I always want some reserve burn time for contingencies. (BTW, don’t get the impression I don’t like great conditions like yours! I’d LOVE them- but we all have what we have out our respective back doors. )

There are no government SCUBA Police (Yet!) so you are free to be a test pilot in conditions less demanding than the worst ISC has to assume their equipment must sustain. Be very careful and keep detailed, thorough records. That is the approach I’ve been taking w/ my experimental homebuilt unit. The extension of my self imposed burn time limit will come in small steps. The methodology will still be to push it hard, cold, & deep but when venturing beyond known comfortable repeatable burn times I’ll plan dives with little to no risk of entanglement w/ limited deco obligations- and carry plenty of bailout! Until I do REAL WORLD testing throwing numbers around is irresponsible speculation- one must simply test carefully with an open mind, accepting the limit when it first whispers its presence. That’s what the word ‘experimental’ is all about!

Best of luck on your project!

Ken

mverick

Thanks for this,

I've been wanting one since before I got my meg. Just a little larger and radial. So, no changes on the dive boat. Or, a long dive. I dive the cold too..

mverick

oh, one question.

How many scrubbers will the 2oz epoxy size do?

Since the mesh is enough for 4 screens. I figured I'd build 4 or 5 out of the plate.

Skipbreather

Hi Rick-

One kit should be good to go for 2 scrubbers, provided there isn’t a lot of wastage. If you had a largish puddle of adhesive left over after each bonding operation on the first unit, I’d have a second kit handy before beginning the last major bonding operation of the second scrubber. Kits only cost in the $20–ish range. Considering the time, effort, & expense involved getting to that last bonding operation, would be cheap insurance. There is no induction time so if you mix not quite enough for any given task, mixing just a little bit more to finish is no big deal.

Best,
Ken

lof

Photos here:
http://www.rebreatherworld.com/megal...ubber-meg.html

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Golem Gear ShopKeeper
www.golemgear.com

DanDunfee

Well done Ken....again... !!
A very good, simple, and innovative design .. excellent workmanship in the DEMA 2006 Demo unit... and an Excellent writeup here!!..

But especially commendable is your willingness to share openly with, and to the benefit of, the rest of the Rebreather Brotherhood,.. rather than playing coy and close-to-the-vest, staging a 'show', and exploiting it as an immediate 'cash cow' by forcing others to come to you for it. Its really a substantial technical and unselfish contribution, and a boon to seasoned homebuilders, on more limited budgets, who can / will make good use of it.

Again.....'Well Done' !!

Dan

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