AT-Pac Restoration

[73diver]

Hi Ron, Sorry I was delayed in responding. You did exactly as I did. Best of luck with your 'new old friend'. For many years I knew no other diving than with my At-Pac and I had some interesting times with it. I recall doff & don drills (with instructor) in a wet suit at 80' for simulated wreck penetration when the other guys were using a weight belt and chest BC. All they had to do was remove their tank over their head and push it ahead of them. It was a bit more work for me. I was also told I couldn't use the At-Pac to dive off a boat in the Keys (in 1976) so my first dive with a chest mounted BC and weight belt was on a charter. Now, one of my regular pieces of equipment is a Hollis C45 wing and backplate. The absence of the 'taco roll' is a plus for the Hollis, but I get the At-Pac out a few times a year to remind me of what it was like when I started diving.

 

[RonMurray]

No worries. Very similar experience. I actually did my certification dives in the At-Pac in Key Largo (lived in Miami) in 1975, although all of our confined water training was in Horsecollars. Next time I went back to get on a charter at Pennekamp they had a sign hanging in the dive shed that said NO AT-PACS. Silly.

I also dive a Hollis 45lb doughnut wing and an AL backplate when diving doubles.

One other upgrade I plan on for mine is to salvage some cam bands from another At-Pac that I bought on ebay some years ago for a few dollars. My original At-Pac had the bolts integrated into the tank bands. Switching tanks meant unbolting the bands from the tank. This other version are just cam bands that remain attached through the backpack. That will allow me to switch tanks more easily.

I still have the ScubaPro second stages I used back then but I long also got rid of the MK VII "honker" that I had in favor of a MK25. Wish I still had the MK VII now. I expect I could find one if I tried hard enough.

I also still have my ScubaPro branded SOS Automatic Decompression Meter (Bend-O-Matic).

I still have the original lead and marbles that was in my unit - but I'm afraid I may need a bit more lead than I did back then... are you using just fishing sinkers?

Thanks for your suggestions and encouragement. AT-PAC DIVERS UNITE!

 

[73diver]

Ron,
Sounds like we followed each other. I had two Mk VII's with lifetime guarantees. One was purchased in 1973 and the other was purchased in 1982 (for my wife). I sent them in for service one time and they both came back as Mk25's. When the water is above 50F, I use the Mk25's. I upgraded the 109's to balanced. I have two sets of At-Pac steel tank bands so I haven't needed to use a cam band yet. I also have the carrying handles that fit the tank bands. I also had a Bend-O-Matic but I didn't really rely on it much.

 

[RonMurray]

You must have been certified NASDS...

 

[RonMurray]

As with most things - two steps forward, one step back.
Treated the shell of my AT-Pac with hair products containing hydrogen-peroxide 12% and have returned my white shell back to white from the nasty yellow it had turned.

Also received the bladder from OMS/DUI, but it was the wrong bladder. 11918040 as opposed to 11918041. So, sending back the bladder with the port for the shoulder hose in the middle of the neck instead of left-offset. OMS/DUI customer support very helpful. Also, having seen that the bladder does not have the threaded attachment point for the BCD hose elbow (or the OP valve) OMS customer support is confirming the parts needed to for both.

20170520_115608

• RonMurray
• May 22, 2017

Comparison of At-Pac Shell. Interiors of shell treated with Hydrogen Peroxide contrasted to...

20170520_115629

• RonMurray
• May 22, 2017

Comparison of At-Pac Shell. Interiors of shell treated with Hydrogen Peroxide contrasted to...

 

[73diver]

Treated the shell of my AT-PAC...

I'm envious. I didn't buy the At-PAC shell back in the day. I hope you're back in the water soon.

 

[RonMurray]

Still working on it - I've had a pretty hard time getting the correct order filled from OMS/DUI. the first bladder they sent had the inflator port center back - I specifically asked for a bladder with an offset port, the rep said they eyeballed it and it was correct. Not so. I talked to different rep - much more knowledgeable - and he set me up with the correct bladder, elbow assembly, inflator hose, double gaskets. I had also asked for OPR valves but they were left off the order. The bigger problem to me was it was clear that the elbow was necessary but not sufficient. I needed a "seat" to which the elbow assembly could attach. I thought this might be part of the elbow assembly but it was not and I was not advised otherwise. No big deal to me, another call, and I have the OPR valves on their way, seats for both OPR valves, and the elbow assembly and another gasket that was shown in the OMS BCD Service Manual which Jay at DUI was kind enough to provide. There is one part that is backordered so it will be July before I do much more on this project.

Once I have all the parts I think this will move along pretty quickly. Maybe you 73Diver can provide some insight on attaching the elbow to the new bladder?

 

[73diver]

I'll share what I did:
1) The stainless steel grommet for the elbow was removed. This left a hole too small for the OMS elbow.
2) I enlarged the existing hole to fit the OMS elbow. At the same time, I offset it as much as possible toward the center line. The OMS offset was not as great as the At-Pac offset.
3) I reinforced the inside and outside with some black ballistic nylon rings that I fabricated from a sheet of unbacked (i.e. no polyurethane backing) nylon. I used a small flame to 'finish' the edges of the nylon. The 'sandwich' of At-Pac nylon shell and two reinforcements were bonded with Aquaseal. On the outside surface, I masked off the area around the reinforcement with painters tape so the glue line would be uniform around the reinforcement.
4) The OPDV was installed the same way.
5) I installed all new inflator, corrugated hose, etc. from OMS. However, my original At-Pac inflator, OPV, etc. cleaned up very nicely and could have been used. The inflator valve was easy to work with and the LP hose that runs inside the corrugated hose was in good shape. I may still revert to the original inflator after giving it a thorough evaluation.

 

[RonMurray]

Finally believe I have my 1975 AtPac ready to get wet! Received the correct parts from OMS/DUI - a bladder, two OPV valves (which are inaccessible on this unit), inflator hose and mechanism, various double-seals, etc. Oh, and two free hats!

Did some more color restoration on the outside shell, installed the new bladder. I have problems with things that are irreversible, so I couldn't bring myself to cut the old grommet off of the should opening of the original bladder cover. So I left it in place. Admittedly, the 90 degree elbow does not extend fully through the grommet - but it doesn't appear to be a problem for me. (I'm not diving this on the Doria).

Reweaved the backpack, wing, and shell back together with the original line. Not difficult at all (picture)



Readjusted the straps. My discomfort at doing things permanently came in handy as when I was originally fitted (age 15 - 32 years and as many pounds ago) I could not bring myself to trim the straps, so I overlapped the extra webbing and secured it with electrical tape. The result being I had plenty of the original webbing to make necessary adjustments. I also had to retrieve the original shoulder buckle that I had salvaged off the unit years ago in a weight belt emergency. But located the original buckle and was able to reassemble the straps as original except for size.

One change I did make to the original was the cam bands. My original unit came with a single steel 72 cylinder (which I still have) that had AtPac bands on it. The bands were regular steel bands with the mounting bolts for the AtPac backpack permanently attached. The idea was to have one of more of the tanks and bands and just unscrew the tanks/bands from the backpack and put a new one on, or fill the one taken off. But I bought another old AtPac years ago that had cam bands that screwed into the backpack in the same way my fixed bands did. So while I will sometimes use my original Steel 72 with the fixed bands, I also have a set of cam bands to use with other cylinders.

As shown in the pics, I have a half dozen steel 77s that I like and am using one of those currently. I attached one of the pool regs I use for teaching. I have a SP Mk 7 that I plan on using with this kit but it requires service.

Also, I kept the original weights that came with the unit (marbles and lead fishing sinkers). Total weight is 14lbs - way more weight than I ever dive with now. With a steel tank and 3mm in salt water I wear a couple pounds, 4lbs at most. But I have the original lead/marbles in a box and I will probably put some of it in the backpack for nostalgia's sake.

The pool at the university where I teach scuba is currently empty. Once it is filled later in the week I'll be submerging with this unit. Can't wait.

 

[Sam Miller III]

Great restoration - appears to be factory fresh right out of the box !
I note you have retained the SCUBA Pro logo - SCUBA Pro officials and the At Pac officials were very tight - All members of the Long Beach "iving mafia" -- a story for another time

I will bet your college dive students will be impressed--What college?

If needed in future I have for sale or trade
* At Pac plastic shell
* At Pac hose inflation unit - complete
* Fail safe - dive safe (or is it Dive safe-fail safe?) regulator -over hauled and it very good condition- Very few were produced and very few have survived the passage of time.

Cheers from Sunny California

Sam Miller,111