Just got some tanks...tell me what to do!

[fishmunger]

Ok, well I bought some steel 72's from craigslist. They had been sitting in a garage for a loooong time. I figured at $15 bucks a pop as-is, it's worth the gamble...so here goes

this one is the newest (74') but in the worst condition. it has some surface rust inside and some corrosion around the boot area. it has 3/4" valve threads.

this one, a 66' is in the best condition. almost no corrosion, 3/4" threads. the galvanizing looks a little different: more "gray-like"

this baby is old. 1960. but in pretty good shape. some corrosion around the boot. It has the 1/2" pipe threads, but the valve looks almost new, so i got it.

2 of the 3 have about this much corrosion around the bottom. there was a lot of salt buildup, but i buzzed some off with the orbital sander to see what lay underneath. it doesn't look deep it all, but I stopped before I dug in, I wasn't sure about getting into the coating...

eyeing one of the tanks...you can see the extent of the corrosion.

QUESTIONS:

how much corrosion is OK?
How should i fix it? Sand it all the way down, use a wire wheel, then repaint with cold galvanizing spray? Should I do this before or after I take in for hydro/viz? Leave it alone?
are they junk?

looking forward to what you guys have to say,

Nate

 

[fishmunger]

this k-valve looks like a POS, but it's small and compact. anyone know what kind it is?

this 3/4" j valve is an 8.5/10. it looks pretty nice.

this 1/2" pipe valve looks super good, a 9/10.


whaddya think?

Nate

 

[DennisW]

Get them hydrostatic tested and the valves overhauled. You may need to get one or two tumbled if they have rust inside the tanks. After they are hydro'd and visually inspected and they have passed all the tests, get them filled and go diving. Wish I had found them. You really can't hardly hurt a steel tank.

 

[captain]

I don't see any rust bleeding through the galvanize under the boot. Just get them hydroed, preferrably take them directly to the hydro facility yourself, don't deal with a dive shop until after the hydro is done. Here is a list of testers, find one near you.

http://hazmat.dot.gov/sp_app/approvals/hydro/hydro_retesters.htm

Nice find, they will be great tanks.

 

[Isaac-1]

The logo on the first valve is the old Sherwood logo (they changed to an S in a circle in recent years). You can still see the old logo on many of the Sherwood products listed on Ebay.

Ike

 

[fishmunger]

cool. so it would be better just to leave the corrosion as is? I was thinkin of possibly dipping the bottoms in vinegar just to eat some of the salt off? I did this when cleaning my conshelf 14 2nd stages and it worked like a charm. However they were chrome plated, and I don't want to do anything that will eat away the galvanizing, only the salt....

Nate

 

[captain]

cool. so it would be better just to leave the corrosion as is? I was thinkin of possibly dipping the bottoms in vinegar just to eat some of the salt off? I did this when cleaning my conshelf 14 2nd stages and it worked like a charm. However they were chrome plated, and I don't want to do anything that will eat away the galvanizing, only the salt....

Nate

If you leave the boots off, which think you should, it will clean off after a few dives. Other than the looks cleaning will not accomplish anything other than taking off good galvanize.

 

[Creed]

Yeah, that white corrosion is essentially harmless. All of my older galvanized tanks have it, to a certain degree. And I second what captain said, take it to the hydro shop directly, then deal with the scuba shop.

 

[JeffG]

How should i fix it? Sand it all the way down, use a wire wheel, then repaint with cold galvanizing spray? Should I do this before or after I take in for hydro/viz? Leave it alone?

Leave the tanks alone and get them hydro'd and vis'd

If you sand and/or paint the tanks, you could very well ruin them for use.

 

[mike_s]

If it was me, I'd just replace the valves.

I bought some one steel 72's a few years back. The valves went one by one slowly leaking "tiny bubbles".

It only cost me a few air fills, but what sucked was getting to the dive site only to find that my tank had leaked out. Luckily I was at a local quarry that had a compressor so I was only delayed about 20 minutes to get a new fill. I could have rebuilt the valves, but they were old J valves and easier just to replace them.