IDA 71 Connectors

GKAM

Hi all,

I am looking to connect BC Direct Feed hoses to the O2 and DIL s/s pipes on the IDA 71 for a KISS conversion. Something similar is located on Diver Dave's pages at http://www.nobubblediving.com/frankensonguts.htm

Does anyone know of an off-the shelf connector to mate the 8mm pipe to the male BC fitting? The thread on the male BC fitting is 3/8 UNF (same as on the LP reg ports). A similar connector is made by Swagelok with P/N B-8M0-7-6RG but the female thread is wrong.

Can you help?

Thx,
GKAM

Crazyduck

Hey there Gkam,

The 3/8 fitting is actually 3/8-24 (24 is a fine thread.)
I am not to sure about the fitting converstion for the 8mm part.
However, there are parts for sale that can convert hose fittings.
Example is a 1/2" hose fitting that was used on the US Divers hoses from the 80's. For this there was a 1/2" to 3/8-24" fitting. I would check with Oxycheq, Omni Swivel and few other sources like trident diving. Dive shops should have access to some if not all of these sources. Another option is take a 3/8 hose and cut the end off and put in the new fitting. If you take this route you will need something to crip the hose with- Mcmaster Carr in the US sells such crimping parts and tools. www.mcmaster.com part no. 6541k67- for the crimping tool (that puts you in the area.)

Please be careful with the IDA-71 Oxygen regulator the parts are Silver Sodered on. Look up Tom Rose and his dive site has some interesting information on the RGU-FM unit.

Give us a yell if this helps.
Regards, Andrew

Skipbreather

Hi GKAM-

First: You do NOT want to use a standard BC connector on the dil side of your IDA71. Reason: A standard BC connector does not flow enough air to allow you to breath anywhere near normally if going semi closed bailout. The 71 has an excellent ADV that is actually the guts from a standard Russian second stage. Putting in a BC connector will make it like breathing thru a cocktail straw. I know. I’ve tried it.

I know Dave used a bin full of various Swagelok parts to get from the 8mm tube to standard connections, but it is just not necessary and, as I said, you remove semi closed as a bailout option. I found a much better way. Simply machine a part from standard ¾” hex 360 brass stock about 2” long. One side will duplicate an Apex/ Mares/ Zeagle/ Poseidon/ Seaquest high flow quick disconnect (male). The other side (female) will be tapped (I seem to recall that it’s a 14 mm x 1.00, but don’t bet on it. Measure your dil input fitting at the bag), but only AFTER you countersink the tap drill hole’s bottom w/ a 90 degree countersink. This will mate perfectly w/ the original Russian dil input fitting. Then hook up w/ a standard Apex QD hose. I’ve made a couple of these and they work great.

A side benefit of doing it this way: There is zero possibility of accidentally cross connecting you O2 and dil hoses. Never forget- Mr. Murphy’s law is alive and well.

A similar trick will work on the O2 input side, but is even simpler. Do the same as the dil side w/ the 14mm female part. The other side of the fitting is simply tapped for whatever BC QD you choose to screw in.

LIFE THREATENING IMPORTANT: Although the 71 is overall a very robust rig, the metal clamps that secure the short hose inside the bag that runs from the exterior exhale hose connection to the “T” (that splits the exhaled breath to the two scrubbers) are total CRAP. They break. Easily. When they break, the short hose eventually slips off. When that happens, a severe hypercapnia hit WILL result. My dive buddy came very close to dying from this weak point. When I overhauled my 71 a couple of years ago, I found BOTH hose clamps broken- waiting to kill me. Keep in mind that a standard negative pressure check will not detect this failure since it is entirely inside the bag.

Dive save,
Ken

GKAM

Thx for the info. I understand what you said about the ADV and the SCR mode. I agree.The second BC connector I have is actually from an old Apeks Drysuit valve and is of larger diameter than what is now used to feed suits and BCs. I think it will be adequate.

The part that worried me a bit was your mention of the failure point in the bag. This is in deed a hazard. What is the EXACT problem with the clamps? Crap as in what sense? I mean this was a Mil Spec rig and this is a serious problem that cannot be easily detected... Please give me some more info before i go hacking at the bag e.g. Under what mode do you think they would fail? Do they rust (v. unlikely i think)? Do they break if messed with? If the bag is pressed?

GKAM

dive2dive2000

Kudos to all you home builders, you guys have BRASS BALLS

Martin

Skipbreather

The drysuit connector you mention is the correct one, I think. I believe it is the same as the one Zeagle uses on their Octo + alternate inflator regulator.

The clamps on the internal hose appear to be made of poor quality metal and the little tab that is bent to secure the clamp eventually breaks at its base. What causes it to break is just speculation on my part, but my guess is that all the bag manipulations involved in regular diving and cleaning are the culprit.

Keep in mind that all of the rest of the connections associated w/ the 71’s bag are secured w/ a crude-but-effective string and tape method. It’s difficult to describe, but it is easy to see how it’s done when you take one apart. When I overhauled mine, to reassemble it I used a strong braided fishing line for the string (NOT slippery monofilament) and for tape I used a self sealing repair tape (the stuff you stretch to half its original width to activate and it seals to itself when you wrap something with it) that is sold in many boating supply stores.


I've burned over an hour trying to post pictures of the above via half a dozen methods w/ no luck- website is definitely NOT user friendly for pictures & no help page. PM me W/ an email address if you want pix.

I hope this helps.

Dive safe,
Ken

schford

Ken,

Can you let me know what problems you are having and I will see what I can do to resolve them - the only one I can think of is you are trying to upload pictures larger than 1 meg.

I do apologise for it not being user friendly and am very open to comments on how we can improve it.

We have a help section for the website in the forums - it is call How do I / RBW site help, and within it there is a sticky on how to use the Gallery.

To summarise though you go into the catagory you would like to upload pictures to - you choose the upload button from menu near the top of the page and then you use the browse button to add up to 10 photos at a times.

Stuart

canuckdiver

Hey Ken, I believe you and I were discussing this before about my unit.

What I did with my exhale hose was to eliminat the "T" (I'm only running one scrubber) and go to the string-and-tape connections on both ends.

As to quick disconnects, I'm running the same, a high-flow on the DIL side, and a standard QD on the O2 side.

Your'e also spot on on the thread size, 14mm x 1.0

GKAM

My IDA71 to KISS conversion is ready. Pics posted in the Gallery.

Thanks to the people that answered my post here. A vey special thank you to Skipbreather for his valuable contribution off list also.

Cheers,
George

Skipbreather

Hi George-

Pictures in gallery look very nice. You have many great dives ahead of you with this rig. Now for both the good, and the not-so-good, news.

The good: I see you are using the original 71 DSV. If you like your rig now, just wait. I used it too, for over a year. It does the job, but at a price. The cost is a somewhat higher WOB. When you get the chance, modify your rig to use larger bore hoses and especially a “normal” DSV. When I did this, I thought I was diving an entirely new rig- the WOB was that much less.

The not-so-good: Like so many 71 divers- myself included- you have gone to a single scrubber. It is indeed the only way to get a decent, compact, diveable rig. For the most part it will do the job satisfactorily, but not in all situations. The single scrubber setup CAN be over breathed. It WILL happen to you someday if you do much diving w/ this rig. The solution? In the short term, if you feel the signs of hypercapnia (jittery, can’t get your breath, maybe even a feeling of impending doom) slow down and let the scrubber catch up. It will in a minute or two. Or, if in a big hurt situation, I always considered doing a dil flush if absolutely necessary. I never had to, but I always thought about it. I tried about a half a dozen types of sorb and found that Sofnolime 8-12 minimized- but did NOT eliminate- the over breathing susceptibility.

Again, enjoy your fine new rig.

Best,
Ken