1970 US Diver's LP72 - Lined or not?

[KD8NPB]

Does this look like a liner?

The interior was a lightly oxidized steel gray color before I tumbled the crap out of it... it just looked like an exceptionally clean tank to me. There were a couple specks of rust on the inside.

Now it has kinda a red hue to it when the light hits it right.

Process:
4 hours - Ceramic Chips w/ 1 tbsp Dawn + 1 gal water
Rinse
2 hours - #3 Glass Bead w/ 1 gal 1:100 Crystal Simple Green
Rinse
Threads scrubbed with brass brush and 1:16 Crystal Simple Green
2 hours - #3 Glass Bead w/ 1 gal 1:100 Crystal Simple Green
Rinse until no bubbles in the shake test
1 gal, diluted Compound O for 5 min
Rinse for 30 seconds, hot water
Blow dry with high pressure Grade E

Ceramic chips - Rinse water poured out red with red sediment
First glass bead - Very slightly gray water
Second glass bead - Clean water

Tank is stamped Catalina.

 

[kwinter]

I've always been told that no amount of tumbling will remove the lining put on the old 72s. And your "after" photo certainly looks clean. So my guess would be that these were not lined to begin with.

 

[james croft]

I have never seen a steel Catalina cylinder. As far as I know they just made aluminum cylinders. Maybe I am wrong and someone can weigh in that has some expertise on Catalinas.

 

[captain]

Looks to never have been lined. I also question the Catalina, most USD tanks of that era were PST or Norris. If it has a C over an L in between the first hydro year and month it is a PST, If it has an N in a diamond it is a Norris.

 

[Nemrod]

I've always been told that no amount of tumbling will remove the lining put on the old 72s. And your "after" photo certainly looks clean. So my guess would be that these were not lined to begin with.

Well, you either heard wrong or was told wrong. It will certainly tumble out. It takes a while and many shops simply do not want to fool with it and would wish you to go away and thus they tell people things like what you heard.

N

 

[Akimbo]

“1970 US Diver's LP72 - Lined or not?”

The 1970 US Divers Catalog says it is:

(a) SINGLE 72-PROFESSIONAL
Tough Molycrome-Steel interior lined tank
available with a galvanized exterior or with
a yellow Tuff-Koate1over galvanized exterior
with No. 0525 "J" valve.

 

[kwinter]

Well, you either heard wrong or was told wrong. It will certainly tumble out. It takes a while and many shops simply do not want to fool with it and would wish you to go away and thus they tell people things like what you heard.

N

Well that is great to hear. A buddy of mine has 2 lined tanks sitting in his basement. He knows he can't get a VIP from anyone (especially not me) and so the tanks just sit there full, waiting for their final dive. But if I could tumble it out for him, that would be great. Any suggestions about what media to use and for how long?

I agree with the folks questioning a steel Catalina.

 

[KD8NPB]

Looks to never have been lined. I also question the Catalina, most USD tanks of that era were PST or Norris. If it has a C over an L in between the first hydro year and month it is a PST, If it has an N in a diamond it is a Norris.

PST = CL stamp? That makes zero sense. lol.

It's a PST then!

“1970 US Diver's LP72 - Lined or not?”

The 1970 US Divers Catalog says it is:

Hmm, it was yellow epoxy on the the outside...but I didn't notice an obvious liner. My LP108 has a liner, and the whole thing is a burgundy color.

Was a steel-gray liner ever used?

 

[Akimbo]

I can't remember the color. I could be wrong here but why not just tumble them? I doubt the reflectivity after tumbling would match even if the color did on patches where a liner remained.

 

[KD8NPB]

I can't remember the color. I could be wrong here but why not just tumble them? I doubt the reflectivity after tumbling would match even if the color did on patches where a liner remained.

I wanted to do these for O2 service so I can PP blend in to them. Hence the glass bead and crystal simple green.

---------- Post added December 29th, 2013 at 01:41 PM ----------

I got some better pictures.

Hopefully they'll shed some more light. The bluish/purple color is caused by the flashlight, it was the only one I could find that I could drop in the tank.






I'll have to reclean them...With all my spelunking, I seem to have contaminated them with some foreign debris.