Attention Steel Tank Dive Ops: HP Hot-Dipped Galvanized are back in production!

[DandyDon]

Tom, I definitely don't know about Aldora but I seriously doubt the large fill station on Cozumel does any vips. There are no stickers on their tanks and unless they are tracking by the numbers on their tanks I doubt it is occurring. I could definitely be wrong but this is my hunch. It is a huge operation run in a assembly line method.

I was surprised to learn that Vips are not required south of the US, any country I guess. I join you in thinking Meridiano doesn't do any, much less quarterly - or anything else they can get away with skipping for that matter.

It would be challenging for any busy operator to Vip tanks quarterly and pull boots weekly. It's possible, but they'd need a larger inventory and a regimated system.

 

[lowviz]

I was surprised to learn that Vips are not required south of the US, any country I guess. ...//...

Don't get me started.

Your tank. If you care about it, look inside now and again. Especially so if you got a convenience fill from a questionable source. The hydro guy/gal is going to look inside every five years. The whole VIP process is a moneymaker and unnecessary wear and tear on manifolds.

Same with the "rounding out" procedure for hot galvanized steel tanks. If it looks like it will pass hydro at 90% just keep going and stamp it. If it looks like it will be close, then dump it and try again.

We have tanks to fill and you are slowing me down...

 

[tbone1004]

I was surprised to learn that Vips are not required south of the US, any country I guess. I join you in thinking Meridiano doesn't do any, much less quarterly - or anything else they can get away with skipping for that matter.

It would be challenging for any busy operator to Vip tanks quarterly and pull boots weekly. It's possible, but they'd need a larger inventory and a regimated system.

vip's are not required in the US either. It is an industry recommendation, not a requirement. The only required VIP is performed before the hydro procedure. VIP was enacted to prevent tanks from getting internally eaten by rust due to improper filling techniques and externally from improper care after the dive.

 

[scubafanatic]

Our tanks get beaten up externally, paint or Galvanization wears off and rust shows, Not a pretty sight for divers even if they do hydro OK. We have 500 tanks to take care of and not all employees or customers show proper concern. Getting saltwater inside was an event in 1996 but was fixed by no longer renting out tanks not in our control. WE also have our own fill station which checks every tank for fill when they come in. Now we keep plastic nets around the tanks at all times except while diving.


Dave Dillehay
Aldora Divers

If memory serves, the Nekton boats ended up abandoning their LP steel painted Fabers for AL tanks for the same reasons, rusty tank outsides didn't project a favorable image.

 

[ggunn]

so the 3 year service life is because they start to look ugly not because they fail hydro or vip? that's a different discussion as you are essentially retiring them to keep things "fresh" and pretty not because they are unusable. In that case then I have no problem with it, but the way you made it sound was that they are no longer usable after 3 years because of wear/tear which certainly is not the case...

All he said was "BTW our tanks last about 3 years in continuous service—but lots of care taken." It didn't look to me like he was trying to make it sound like anything in particular.

 

[lowviz]

Faber (with XS Scuba) has reintroduced HP Hot-Dipped Galvanized scuba tanks ! ...//...

I find this to be odd: Hot Spray Exactly what is "Hot Spray"?

 

[BRT]

Our tanks get beaten up externally, paint or Galvanization wears off and rust shows, Not a pretty sight for divers even if they do hydro OK. We have 500 tanks to take care of and not all employees or customers show proper concern. Getting saltwater inside was an event in 1996 but was fixed by no longer renting out tanks not in our control. WE also have our own fill station which checks every tank for fill when they come in. Now we keep plastic nets around the tanks at all times except while diving.


Dave Dillehay
Aldora Divers

That was my guess. I've seen some steel tanks in Mexico that were ugly enough on the outside to worry me and they were in hydro.

 

[cool_hardware52]

I find this to be odd: Hot Spray Exactly what is "Hot Spray"?

Google "flame spraying" I've had many steel tanks prepped and flame sprayed with zinc. It's great, a bit thinner than hot dipped, but very very effective.

Many years ago it was possible to get galvanizers to hot dip pretty much any thing including tanks. A steel scuba tank is *very buoyant* in a tank of molten zinc, so special racks that could force the tanks into the zinc were required. I had a dozen LP 72 dipped using racks I built and furnished to the galvanizers.

They no longer will do it. Trust me I tried to find a galvanizer in so cal that would consider the job.

I still have two of the 72's from the dozen. They still pass hydro. I also learned that hot dipping epoxy lined tank was a great way to remove the lining, it's mostly turned to ash and tumbles right out.

Failing at finding a hot dipper, I went with flame sprayed, and have been quite please with the results.

The flame spraying process does not elevate the temperature of the tank very much and is quite durable and self healing. The finish is bit like 80-100 grit sand paper, but one can "burnish" this easily with a smooth hard steel dowel. The burnish tanks are much easier on wet hands.

Tobin

 

[lowviz]

Google "flame spraying" ...//...

Did that when the thread was first posted.

Most impressive job on pursuing true hot-dip galvanizing! It works and produces a wonderfully adherent, attractive, and protective coating on most ferrous alloys. Forget the BS about why it is inferior.(hydrogen embrittlement, heat altering the alloy) to flame/plasma spraying as there are known ways to easily get around those advertising claims of hot-dipping's alleged shortcomings.

Lifetime is what concerns me.
http://www.galvanizeit.org/uploads/publications/Galvanized_Steel_vs_Zinc_Spray.pdf
Run down the center column of the table ("Characteristic") to "Durability". Look to the right and left to compare Hot-Dip to Hot-Spray. Those times vary greatly. There is also a bit more text at the very bottom.
So this stuff will only last a decade or two unless it is painted?

Painted tanks are a deal-breaker for me.

 

[cool_hardware52]

Did that when the thread was first posted.

Most impressive job on pursuing true hot-dip galvanizing! It works and produces a wonderfully adherent, attractive, and protective coating on most ferrous alloys. Forget the BS about why it is inferior.(hydrogen embrittlement, heat altering the alloy) to flame/plasma spraying as there are known ways to easily get around those advertising claims of hot-dipping's alleged shortcomings.

Lifetime is what concerns me.
http://www.galvanizeit.org/uploads/publications/Galvanized_Steel_vs_Zinc_Spray.pdf
Run down the center column of the table ("Characteristic") to "Durability". Look to the right and left to compare Hot-Dip to Hot-Spray. Those times vary greatly. There is also a bit more text at the very bottom.
So this stuff will only last a decade or two unless it is painted?

Painted tanks are a deal-breaker for me.

Ya I'd be really disappointed if after a "decade or two" if I had to have my tanks sand blasted and resprayed......

The reality is tanks that aren not hot dipped when manufactured are never going to be. Flame spray is a very good second best.

Tobin