Spec Boot For Mk-15

[lowviz]

I bit off a bit more than I could chew with the 12" vacuum chamber. Enormous forces! All but solved, machined a very thick transition ring that keeps my window at 9" yet I still get full use of the chamber. The first bottom plate that I tried kippered. Just got a new one that WON'T.

All part of the Sunfish Pond project. Endless...

Edit:
I got called on my slang. Kipper: Picked it up from a Navy bud of mine. Mixed units. ki (kilo) p (pound) as in to crush under pressure.

 

[Couv]

Kinda of inadvertently tested the boot for function this weekend. Decided to dive BM/SM off my kayak and the boot was on my SM regulator. I haven't packed the chamber yet, so just pulled the boot up a little to flood the chamber with water. Seemed to breathe fine on surface, so I left it that way for the dive. Completely forgot about the boot being on there until I was cleaning my gear - we can say it worked flawlessly with a seawater packing. Did 2 more dives with it seawater packed and again I couldn't tell it was on.

Dive depths were 41, 71, 49 feet respectively.

Tigger, that sounds promising. Re the test, I have a question (and of course a suggestion.) Did you use a balanced second stage? If so, it might help to compensate for the loss of IP the first stage would have suffered as you were going deeper and deeper with a boot that did not transmit ambient pressure correctly.

A friend of mine did an experiment a few years ago on several regulators outfitted with modified intermediate pressure gauges. The gauges were simply modified with a hole in the case to allow ambient pressure inside so that the indication was always ambient + IP. As predicted, the IP remained the same regardless of depth.

My suggestion is to do the same experiment on your packed and booted first stage. If the boot is not transmitting the ambient pressure it will be indicated by a loss in IP as the regulator is taken deeper.

 

[raftingtigger]

Couv, I used a newer MK5 1st stage rigged with a DIN connection and a R109A (not BA) as my second. I can tell the difference between the reg I use and most others I have be offered (mine breathes much better) and I can tell if I have the adjustment knob screwed in. It breathed fantastic through the whole dives.

As for the IP gauge idea: interesting, but I don't have one to dedicate and lose to corrosion from using it in salt water.

Another testing idea is to take 3 tanks out on a dive (BM, SM, pony) and have BM unmodified, SM with the SPEC boot, and pony with stiff tape over the holes. The stiff taped pony regulator would act as the control for no ambient adjustment, while the unmodified BM one as the control for a normal ambient adjustment. Should be safe, I can always go back to BM or take the tape or boot off the others. Not that I'll ever test beyond about 4 ATA.

Just an off-the-top calculation: IP on my regs is approx 130 psi, subtract an additional 3 atm (depth of 99 feet) and the effective IP with blocked ports should be about 85 psi. Anyone know at what IP the reg will start breathing hard at a relaxed inhalation?

 

[redacted]

A water pressure gauge used to test house pressure can be found at Home Depot for $10

 

[Couv]

Yes, any cheap gauge will do as consistency rather than accuracy is the concern. One gauge on one regulator at several depths if what you're looking for. I'll donate one for the cause, PM me with your snail mail and I'll get it out to you.

BTW Master Awap was one of the test dummies.....er pilots in the experiment and provided very useful and detailed data.

 

[Luis H]

Here is the gauge I used for the testing that Couv is talking about.

Compact IP Gauge (PSI and BAR) | Dive Gear Express®

At $8 per gauge (including the QD fitting) I actually purchased several. I checked them against my calibrated digital gauge standard ad they are very accurate, but as Couv mentioned that is not critical.

I drilled large holes on the case to make sure water flowed freely and I could rinse them in fresh water as soon as possible. The internal all seem to be brass so it held-up well, only the labels on the dial got a bit faded, but it is not bad for what I considered a disposable gauge.

I also put together a “Y” adapter so that I could attach it to the BC hose and still use the inflator for the BC. I use that adapter to put two IP gauges side-by-side to check their accuracy.

I will try to post a picture of the set-up tomorrow.

As Couv mentioned, Awap took some of the data with his Scubapro regulator (I think it was a MK-7).

I was testing one of my double hose regulators and a Conshelf first stage with a dry environmental chamber.

 

[raftingtigger]

Yes, any cheap gauge will do as consistency rather than accuracy is the concern. One gauge on one regulator at several depths if what you're looking for. I'll donate one for the cause, PM me with your snail mail and I'll get it out to you.

BTW Master Awap was one of the test dummies.....er pilots in the experiment and provided very useful and detailed data.

PM sent

 

[raftingtigger]

Seawater packed. Max depth 47 feet. IP steady regardless of depth. I'll do it again tomorrow with hopefully a deeper depth. Breathed sweet.

Next try will be silicone packed.

 

[Luis H]

I meant to post this earlier. I see that you already have used an IP gauge underwater.

The “Y” fitting on the bottom is what I used to share one hose for the inflator and the IP gauge. I normally use this fitting to check the accuracy of IP gauges against my digital gauge. The digital gauge was verified against a calibrated precision gauge.

The gauge on the left has been on several dives and it’s a bit cloudy when compared to the one on the right.

Here are a couple of pictures showing the holes I drilled to help rinsing the inside of the gauge. You can see a bit of corrosion, but not bad.

 

[rsingler]

Couv, I used a newer MK5 1st stage rigged with a DIN connection and a R109A (not BA) as my second. I can tell the difference between the reg I use and most others I have be offered (mine breathes much better) and I can tell if I have the adjustment knob screwed in. It breathed fantastic through the whole dives.

Just found this fantastic thread. A Major League version of a thread of mine from years ago. But then this thread stopped!

What happened?? Did the mold process work? Did you make a few? I want ten for my Mk 10's!!!! Lol!

After reading through fifteen screens, I just about fainted when there was no happy ending. Can anyone bring me up to speed?