BigSwell
Master Diver
Posts: 128
Joined: Thu Apr 18, 2019 6:57 pm
First Name: Kevin
Location: Kalifornia

Painting Tanks

Sat Oct 16, 2021 11:44 am

I have a steel tank which is spray painted over the galvanized exterior. Up until yesterday, I've had no problems regarding its appearance or it being questioned while having it hydro'd, VIP or filled at dive shops. It's currently in hydro/VIP with no visible signs of rust ect. So I go to get it filled yesterday at a local dive shop and the person there asked me if it was painted and I said yes, I told her it was spray painted. The owner of the shop told her that's a problem because certain paints can cause weaking of the metal and possible explosion potential. He said if he sees tanks painted he is required to send them for hydro before filling them. I understand if a tank is heated or powercoated this could cause issues but I was clear it's spray paint out of can from Home Depot. They decided to fill and I was on my way. My question for those on the forum is if there are CGA, Hydro, or other regulations etc AGAINST spray painting scuba tanks. If so, can you direct me to any published regs etc? Thanks in advance.

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antique diver
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Joined: Sun Dec 10, 2006 12:50 pm
First Name: Bill
Location: North-Central Texas

Re: Painting Tanks

Sat Oct 16, 2021 12:00 pm

No regulations about that kind of painting as far as I know. It cannot hurt the metal. Finishes requiring a heat cure is a different story. Luxfer says that any cylinder heated to 350 F. should be condemned.

I mainly spoke up to suggest that there should be regulations against ignorant dive shop personnel. :evil:
The older I get the better I was.

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antique diver
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Joined: Sun Dec 10, 2006 12:50 pm
First Name: Bill
Location: North-Central Texas

Re: Painting Tanks

Sat Oct 16, 2021 12:15 pm

Direct from Luxfer:

Luxfer’s Guide to Scuba Cylinder Visual Inspection (Second Edition)
RECORD what you know or can see about the cylinder-cylinder condition (signs of
wear), maintenance, exposure to unusual treatment or conditions, evidence of exposure
to heavy service or extreme/hazardous service, (see section I above and

Glossary in APPENDIX G for definitions of the types of service) or knowledge about
exposure to heat and/or fire.
RECORD fresh paint if found. If fresh paint is found, get information from the owner
about how and why it was painted and how the paint was cured and dried.
RECORD this information on THE FORM, too.

CONDEMN all cylinders exposed to heat over 350°F or that have been exposed
to fire, or that the inspector has reason to believe may have been exposed to a
heat over 350°F.



WARNING: If you suspect a cylinder has been heated to temperatures
BETWEEN 265°F (130°C) a retested prior to use. Cylinders exposed or with
evidence of exposure to heat in excess of 350°F from service.
CONDEMN all cylinders which exhibit any arc or torch burns, or fire damage.
(See PHOTO 13.)

CONDEMN all cylinders that were repainted and heated over 350°F to dry or
cure the paint.

HOLD all cylinders with fresh paint for a hydrostatic retest, unless the inspector
is sure the fresh paint doesn’t hide an imperfection (see ‘imperfection’ in
Glossary.G Fresh paint may also hide heat damage.
WARNING: Do not return to service any cylinder with hidden heat or physi-
cal damage that can’t be visually inspect
The older I get the better I was.

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luis
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Joined: Thu Jun 30, 2005 9:28 pm
First Name: Luis
Location: Maine

Re: Painting Tanks

Sat Oct 16, 2021 4:50 pm

antique diver wrote:
Sat Oct 16, 2021 12:00 pm
No regulations about that kind of painting as far as I know. It cannot hurt the metal. Finishes requiring a heat cure is a different story. Luxfer says that any cylinder heated to 350 F. should be condemned.

I mainly spoke up to suggest that there should be regulations against ignorant dive shop personnel. :evil:
I have to agree.


AFAIK, Painting scuba cylinders got a bad reputation due to two incidents in Florida (on the same day).

There were two cases in Florida, where two cylinders ruptured due to heat related paint that ruined the aluminum heat treatment. Like Bill mentioned, aluminum can be ruined with temperatures as low as 350F.

The incident was a while back, I think in the 80's. Both cylinders belonged to the same person.

The story as I remember it, is that one blew up in one dive shop. It didn't hurt anyone, but it did a lot of damage to the dive shop.
The owner of the cylinder was pissed that his cylinder blew up, but he decided to take his other cylinder to a second dive shop, on the same day. If I recalled someone did get killed in the second dive shop. :(


These were aluminum cylinders, but differentiating aluminum from steel can be too technical for some dive shop owners. :roll:
Luis

Buceador con escafandra autónoma clásica.

BigSwell
Master Diver
Posts: 128
Joined: Thu Apr 18, 2019 6:57 pm
First Name: Kevin
Location: Kalifornia

Re: Painting Tanks

Sat Oct 16, 2021 4:53 pm

Thanks for the info guys, I appreciate the time you took to reply. I've literally been doing this since the 90's with my HP steel tanks and this is the first time someone has questioned my tanks. And I've never had an issue with hydros either. Hopefully this was an isolated incident and I won't have to explain this again to this shop. Once my fill card it used up I'll go somewhere else for air.

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luis
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Joined: Thu Jun 30, 2005 9:28 pm
First Name: Luis
Location: Maine

Re: Painting Tanks

Sat Oct 16, 2021 5:00 pm

I should have added, that painted aluminum cylinders (not factory paint) are often rejected by many dive shops. That practice is not totally unreasonable, since there is no real way to determine if the paint process involved any type of heat (flame spraying or baking, etc).

Carrying that practice over to steel cylinders is not justified at all.
Luis

Buceador con escafandra autónoma clásica.

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