New life for an old MK3

[ZKY]

A friend of mine gave me this old Scubapro MK3/108 reg.
It's probably from the mid to late 60's, thin yolk, 2 LP ports & one HP port.
The thing has quite a history. First of all it was never serviced once in it's entire lifetime.
The guy who gave it to me was primarily a freedive spearo. He only used the reg occasionally to go deep in Florida to shoot groupers and also to dive in Southern California for scallops and occasionally lobsters. He actually could care less about scuba or the gear.
He only used it with one single second stage, no octo or SPG. When it got hard to breath he came up. It was about as simple as that.
He actually bent himself while using this reg. He was diving in Florida and went to 200 feet on a single AL 80, no SPG, on air. He was doing his stops according to navy tables and ran out of air somewhere in the 50 foot range and had to do a free ascent and as such blew off a bunch of deco, (yeah I know, genius!). The result was within a few minutes his shoulder blew up with gas under the skin (subcutaneous embolism) and looked like somebody filled his skin with air. After that his shoulder hurt like hell in the joint and since then he's had 5 surgeries to try and fix the damage. He never did go to a chamber. That was probably 20 years ago
I'm not sticking up for the guy and I certainly don't approve of his cowboy diving but those are the facts.
The point is, that simple little MK3 went to 200 feet and worked fine.

When I got it it was nasty, corroded, frozen up, it had never even been rinsed one time after he used it in salt water!
I very carefully took it apart and the chrome was so bad and pitted that I decided to just strip it off and try polish out the brass. So far I have the 1st stage done and I've almost got the yolk done.
Next I'm going to work on the diaphram cover and the clamp rings. I don't know what I'm going to do with the 2nd stage body yet, if I'm going to just clean it up or strip off the chrome and polish it.
After all that I'm going to soak it and rebuild it. It's about the dirt simplest reg internally I've ever seen.
I don't have an ultrasonic cleaner. I was thinking of getting one of those $79 ones at Harbor Freight but I'm wondering if CLR would work. It's supposed to disolve salts, scale, rust, corrosion, etc.
Can anybody advise on CLR to soak reg parts?

Here are a few photos of my progress so far:
The pics of the second stage are obviously before shots. Stay tuned, when I am done they will be beautiful!
The first stage used to look like the 2nd stage parts you see.

[knowone]

Beautiful.

Who will be the first to figure out how to seal polished brass?

Hot vinegar and a brass brush works best for cleaning
crud.

The main reason for an ultrasonic is to be able to use
non corrosives, and let the vibrations do the business.

When I'm not in a hurry and want to strip some chrome from crevices I half submerge the part in vinegar in a sealed container, turning the part over every couple of days, and the infused air and condensation does
the business.

Very good luck.

Leave the serial number till last.

Gotta gobay.

[ZKY]

I'm just going to leave it open so it can breathe. It might tarnish a bit but it will have that "vintage" antique look. I will polish it up quickly by hand with a little Brasso periodically like an old tea pot.

[knowone]

Or a magic regulantorn.

[Akimbo]

I can’t remember the model names but were these the same model second stage? These were circa 1964. Actually, these had pretty terrible performance even by the low standards of the day.

[Zung]

These appear to be SP 108 "High Performance" seconds. Simple downstream regs, but their performance should be on par with their more modern descendants such as the R190, 290, 390, and other brands too. Not the greatest breathing regs on earth, but livable.

ZKY: great job you did on the first! Can't wait to see the 2nd.

[Akimbo]

These appear to be SP 108 "High Performance" seconds. Simple downstream regs, but their performance should be on par with their more modern descendants such as the R190, 290, 390, and other brands too. Not the greatest breathing regs on earth, but livable...

Your post got me curious enough to look it up. The 1964 catalog describes them as Scubapro Regulator Mark I (#7100) and Mark II (#7105) — pages attached. Are these the same? I remember deciding to scrap them for brass rather than sell them around 1972 because of performance issues. Nobody except EDU had breathing machines them but the side-by-side test with a Conshelf XI convinced me it was better off recycled.

[Zung]

Hey, you got me curious too, so I downloaded all the SP catalogs from here (http://scubaadventures.eu/index.php/service-a-owner-manuals/scubapro/2292-catalogs). I'm old, but not that old to speak with any kind of authority about things that dated back to the early 60's: I was only a boy then. :D

Anyway, here's what I found:

Up to '67: there was only 1 second stage packaged together with the first stages, and the packages were called by the first stage name. The second stage looked A LOT like what's known now as the "108"
In 1970, the "Adjustable" appeared, and was christianed "109", which is the catalog number.
Only in '77, along with the appearance of the Pilot, the "Second Stage Downstream" got its now-official name of "108" (cat. no.)
Finally, in '80, each package got a "fully qualified" name, i.e.: "MK III AND 108 REGULATOR"

Another thing: there are 2 kinds of 108's: one without the orifice and one with. Whether there's an impact on performance I don't know.

Maybe an elderly guru can confirm the performance problem you mention is from the 1st stage, or from some grossly mis-aligned units?

By the way, and sorry for a slight hijack: isn't this a beautiful BP/W? It's from the '76 catalog:

http://yfpn0w.blu.livefilestore.com/y1paNUYxPQ-QTlFjB2Bwj0KuYrWPQiJDifZBFODvoXw_shueUpEQULifzjLFV K_iFsMoTmLx3UpQLwsAUC6r3b7zDRIEuYiUZ43/Scubapro-BP-W-76.jpg?psid=1

[ZKY]

Wow!

That pack and wing looks surprisingly modern.
And to think it got buried away when the poodle jacket came along. I guess they thought it was a bad idea.
Just look around today and what do you see?

[herman]

That can't be a BP/wing, don't you know they are the latest and greatest thing. :)

[Akimbo]

That can't be a BP/wing, don't you know they are the latest and greatest thing. :)

What I want to know is how they made a cheap plastic copy of the Freedom Plate! ;)

[Zung]

No they aren't: they were superseded by the stabilizing jacket a couple of year later. So I'm keeping mine for the day when these'll come back in fashion and I'll be in the bleeding edge again.

Anybody remember the bell bottom pants? :D

[couv]

Before I thinned out my herd, I had an old MK2/108 (had an adjustable orifice) that breathed every bit as well as my friends MK2/R190. I'm the one who cleaned and tuned both setups, so it's not a question of different techs. Akimbo, do you recall if those second stages had an adjustable orifice?

The back inflate BCs got undeserved bad press, probably from competitors of SP and the At-pack (Watergill if I recall)...."That BC will hold an unconscious diver face down!" was the common attack. I still have an old inflator from an At-pack. They were really cool. The inflator hose ran inside the corrugated hose. I'd like to see that idea coupled with an AIR 2 or something similar.

Bell bottom pants? Have they gone out of style? Darn....nobody told me. :-O

[awap]

I think it was back around 1970 that Scubapro hired a marketing specialist named Manny O. Hale who had a lot of diving experience and recognized that such a contraption severely limited marketing potential and convinced the company to go with the now conventional BCD. This allowed things like sizing, pockets, attachment points, surface performance and many other design considerations to become marketing variables which would increase potential sales.

:popcorn::rofl3:

[Akimbo]

... Akimbo, do you recall if those second stages had an adjustable orifice?...

Holly crap, that was like 40 years ago. I was 13 when I traded for them, long before doing my own service. I am not sure what you mean by adjustable orifice. Not a dial-a-breath style spring counterbalance???


... The back inflate BCs got undeserved bad press, probably from competitors of SP and the At-pack (Watergill if I recall)...

I didn’t think much of the At-Pack fiberglass shell or even their shot-filled back pack, but the elastic covered bladder and brass inflator/deflater served me well for years of sport and some commercial diving. I married the wing to a blow-molded back pack like the ScubaPro pictured above.

For those who have not seen it, At-Packs had a brass fitting near the bladder where the LP hose connected and the corrugated hose. The LP hose then ran inside the corrugated hose to the inflator/deflater valve with mouthpiece for oral inflation. Exhaust was a little slow, but it was a clean package and the added weight of the brass valve kept it in place nicely.

Here is a photo from vintagedivertreasures.com (http://vintagedivertreasures.com/VDTdecalPage3.htm)

http://vintagedivertreasures.com/JAnewdecal1.jpg

[couv]

Not the dial-a-death knob....the other end where the hard and soft seat mate. I haven't come across any, but I was given to understand the early 108s had a non adjustable orifice fixed into the inlet valve. Here is an adjustable one, see item 12 http://www.scubaproregulatormuseum.org/108_HP.JPG

[Akimbo]

Not the dial-a-death knob...

The linked drawing is dated 1988… definitely not the same. The ones in the photo had a very odd bubble rubber whisker/diverter that was not used very long. This was my first single hose after a Voit V66 Navy double hose. In hindsight, I should have gotten the US Divers Calypso. This was not ScubaPro’s finest product.

[awap]

Before I thinned out my herd, I had an old MK2/108 (had an adjustable orifice) that breathed every bit as well as my friends MK2/R190. I'm the one who cleaned and tuned both setups, so it's not a question of different techs. Akimbo, do you recall if those second stages had an adjustable orifice? :-O

I have one 108 with a fixed orifice. I picked it up in a lot of three regs including two 109s figuring I could use the parts. But even the 108 ended up working. Much to my surprise, it breathes on par with an R190. I do use it occasionally as an alternate.

BTW, the mail brought a surprise today. Thanks

[ZKY]

Is the rubber purge botton the same in a 108 as a 109?
So far after soaking the parts everything is looking great. The exhaust T will work, there one small crack in it but I think neoprene wetsuit glue will fix that.
The blue silicone diaphram looks to be in OK shape and useable. I flipped both soft seats. Both hard seats look to be in great shape with no pitting on the edges.
Basically all I need is a rubber purge button an O rings. Brother Couv is going to help me out with some stuff (we need a salom smiley).
I guess I need to get in on the group buy if this metal SP habit keeps up. And I thought collecting double hoses was the evil habit to watch out for! :shocked2: :rofl3:

[Zung]

We should stop talking about those old no good stuff NOW!
The last one I watched (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p4340.l2557&rt=nc&nma=true&item=260749465115&si=0Hks8uODUG93uJnSljHqSF%252FQrNQ%253D&viewitem=&sspagename=STRK%3AMEWAX%3AIT) went for $165.99! That's totally UNACCEPTABLE!

For the cracks in the exhaust Tee, I tried Aquaseal (McNett) with a tooth pick. It's been holding up well after... 2 weeks. :D

[awap]

Is the rubber purge botton the same in a 108 as a 109?
So far after soaking the parts everything is looking great. The exhaust T will work, there one small crack in it but I think neoprene wetsuit glue will fix that.
The blue silicone diaphram looks to be in OK shape and useable. I flipped both soft seats. Both hard seats look to be in great shape with no pitting on the edges.
Basically all I need is a rubber purge button an O rings. Brother Couv is going to help me out with some stuff (we need a salom smiley).
I guess I need to get in on the group buy if this metal SP habit keeps up. And I thought collecting double hoses was the evil habit to watch out for! :shocked2: :rofl3:

All parts on the front of the case are interchangeable with the 108/109/156.

Have you looked at a Pilot yet?:D

[ZKY]

All parts on the front of the case are interchangeable with the 108/109/156.

Have you looked at a Pilot yet?:D

A pilot?

[awap]

A pilot?

Second (http://www.scubaproregulatormuseum.org/The_Regulators/Second_Stage/Second/second_33.html)

The original version had a pilot valve that apparently was too complex for many techs to service. It was then "upgraded" to a coaxial valve which takes the same service kit as the D-series and performs similarly (maybe a bit better due to the very large exhaust valve. They are usually a bit more pricey than the 109/156 and replacement diaphragms (exhaust valves) are hard to come by.

You're hooked. :D

[Zung]

So complex Pete Wolfinger made it the final test to close the section on regulator theory in his "Regulator Savvy" book, page 94-102.

Nobody passed the test. :D

[couv]

I think DA, Matt, and Awap could rebuild and tune those Pilots and Scrotums with their eyes closed. Did one of you guys snap up that Pilot recently on eBay?

[superstar]

My first BC was the Scubapro BCP. It was given to me in exchange for work on I did on a dive boat. The air bladder got soo bad it disintegrated so I stuck a Deep Outdoor bladder on it. I still use the BC.

[AFdivedoc]

I realize this thread is several months old now, and the recent discussion centered on reconditioning the 108 second stage, but I recently found another way to put those old Mk 2s and Mk 3s back in to service. I came into possession of a couple of these old regs with only 2 LP ports, one HP port, the older low pressure yoke, and the flat filters. I figured they would make dandy deco regs if I could convert them to DIN along with the overhaul. The current SP DIN converter won't work because the regs have a non-removable piece the yoke fits on vs the screw-in adapter with the conical sintered filter seen nowadays.

What modern regs still use flat filters, have a similar yoke attachment and have a currently available DIN converter? Sherwoods do! I had one of the DIN fittings lying around and tried it--it works perfectly, and I did some shallow water testing before using the Mk3 on my deco bottle the other day. It is perfect for this purpose and performs as well as my newer Mk2s. A friend had a 2 more Sherwood DIN converters I was able to get for cheap, and they went on a couple of older Mk2s. Had to get an adapter for the HP hose, since these regs take 3/8 HP fittings vs 7/16.

[DA Aquamaster]

The Pilot has lots of little pieces but once you understand it it's possible to tune it. I'd never call it easy as they are pretty sensitive. one issue I noted is that you need to use a mouthpiece with pretty thick bite tabs, especially if you have large
front teeth. If there is not enough area to accomodate the substantial air flow, the Pilot will chatter at depth.

Scubapro had an Air 1 conversion kit for the Pilot that gave it Air 1 internal parts. They are a lot easier to tune and offer about 95% of Pilot performance with less complication. I still have an unused conversion kit in need of a Pilot.

[DA Aquamaster]

Hey, you got me curious too, so I downloaded all the SP catalogs from here (http://scubaadventures.eu/index.php/service-a-owner-manuals/scubapro/2292-catalogs). I'm old, but not that old to speak with any kind of authority about things that dated back to the early 60's: I was only a boy then. :D

Anyway, here's what I found:

Up to '67: there was only 1 second stage packaged together with the first stages, and the packages were called by the first stage name. The second stage looked A LOT like what's known now as the "108"
In 1970, the "Adjustable" appeared, and was christianed "109", which is the catalog number.
Only in '77, along with the appearance of the Pilot, the "Second Stage Downstream" got its now-official name of "108" (cat. no.)
Finally, in '80, each package got a "fully qualified" name, i.e.: "MK III AND 108 REGULATOR"
Another thing: there are 2 kinds of 108's: one without the orifice and one with. Whether there's an impact on performance I don't know.

Maybe an elderly guru can confirm the performance problem you mention is from the 1st stage, or from some grossly mis-aligned units?

By the way, and sorry for a slight hijack: isn't this a beautiful BP/W? It's from the '76 catalog:

http://yfpn0w.blu.livefilestore.com/y1paNUYxPQ-QTlFjB2Bwj0KuYrWPQiJDifZBFODvoXw_shueUpEQULifzjLFV K_iFsMoTmLx3UpQLwsAUC6r3b7zDRIEuYiUZ43/Scubapro-BP-W-76.jpg?psid=1

I learned to dive with one of these - purchased used in the early 80's. I think they were a mid 70's design - I'll check the catalogs tonight to see when they first appeared. I upgraded mine with the soft band to replace the metal band as it was lighter, a lot easier to pack in a dive bag and was less snag prone, and then ended up using it with doubles anyway.

The hole centers were not the current 11' centers, but otherwise it was basically the equivalent of a modern "hog" BP/Wing. The inflator hose was too long but it could be replaced with a shorter one as the diameter was stanbard, and the inflator used a proprietary QD fitting, but again could be replaced - and the later version of the fitting fit on the end of any LP reg hose. In the late 80s everyone started adopting a common QD fitting that was almost identical to the one used on the by then doiscontinued Watergill AtPac.

I dove my Scubapro Buoyancy Control pack until I wore it out (the seams had a tendency to leak), then I endured a stab jacket for several years before wings became generally available again.

[couv]

Larry,

It's a good thing you wore out that bladder. It's a KNOWN FACT that those type of back mounted devices would hold an unconscious diver face down and drown them. :-)

c