Worthington LP7-77 vs Alum 80

[Divin'Papaw]

The only concern I have with these tanks is how durable and long lasting the cold zinc galvanizing process is compared to the hot-dipped galvanizing process they use on their other tanks. They chose that process I believe to keep the costs down, so I assume it's not quite as durable. However, I don't know what the actual difference is in the end. Can anyone shed any light on the difference between the two galvanizing processes?

 

[Luis H]

Hot dip galvanizing is almost indestructible. I have tanks from the late 50’s and early 60’s and the galvanized protection is in great shape.

I would never again own a steel tank that is not galvanized (in some form). I dive in salt water most of the time.

My limited knowledge of the cold galvanizing is that it does chemically bond to the steel in a similar way as hot dip, but it is not a thick or durable. It provides a much higher level of protection than any paint (or similar coating) because the zinc is bonded to the steel and does not allow rust to travel under the galvanizing coating (if the coating is scratched at any point).

The cold galvanizing (or galvanizing paints) can be scratched or scraped with abuse, but the metal still receives protection from the zinc. Then all you have to do is touch up the compromised spot with galvanizing paint. My understanding is that they put a protective coat over the cold galvanizing to mechanically protect the galvanizing coat.

If anyone has better knowledge, please correct me if I am wrong or please add to the explanation.

I have used galvanizing paint on old steel tanks and to touch up the bottom (under the boot) of some heavily abused galvanized and it works great. Rust never travel under the paint even if the coating is compromised.


Are this LP 77 steel tanks cold galvanized for sure? I keep on hearing conflicting reports. It does seem that they are not hot dipped (or they would have made it very clear that they hot dipped).

 

[rleslie]

From the Worthington web site:

LP-Series
Low Pressure - 2400+ psi service pressure
Five different models, Two different diameters

Hot-dip galvanized exterior finish
Chromium Molybdenum steel construction
"Plus" rated for 10% overfill to 2640 psi
Compressor-friendly, lower pressure
Standard "Yoke Style" Thermo PRO valve
Inlet thread is standard 3/4"-14 NPSM
Traditional, proven design
Negatively buoyant throughout the dive
Manufactured to DOT 3AA standard
Meets Canadian TC3AAM specifications

 

[Rainer]

From the Worthington web site:

LP-Series
Low Pressure - 2400+ psi service pressure
Five different models, Two different diameters

Hot-dip galvanized exterior finish
Chromium Molybdenum steel construction
"Plus" rated for 10% overfill to 2640 psi
Compressor-friendly, lower pressure
Standard "Yoke Style" Thermo PRO valve
Inlet thread is standard 3/4"-14 NPSM
Traditional, proven design
Negatively buoyant throughout the dive
Manufactured to DOT 3AA standard
Meets Canadian TC3AAM specifications

Yes, but the LP-77s are not hot-dip galvanized...

 

[rleslie]

Yes, but the LP-77s are not hot-dip galvanized...

What information is your statement based on? I can find nothing on their site that indicates anything other than what I posted.

 

[Rainer]

What information is your statement based on? I can find nothing on their site that indicates anything other than what I posted.

Search is your friend:

http://www.scubaboard.com/forums/2733997-post5.html

 

[Divin'Papaw]

Search is your friend:

http://www.scubaboard.com/forums/2733997-post5.html

Excellent! Thanks Rainer. It appears that both finishes are indeed outstanding. But I'm still very glad that I went with my hot-dipped HP100s.

 

[rleslie]

Yes, but the LP-77s are not hot-dip galvanized...

Ranier, I apologize for doubting your wisdom.

No they are not. All of the other steel cylinders are hot dip galvanized. The LP 77 uses a cold fusion process that essentially sprays the galvanization on to the cylinder.

All steel cylinders sold by XS Scuba come with our exclusive Lifetime Warranty against exterior corrosion issues.


~ XS Scuba

 

[Rainer]

Ranier, I apologize for doubting your wisdom.

No they are not. All of the other steel cylinders are hot dip galvanized. The LP 77 uses a cold fusion process that essentially sprays the galvanization on to the cylinder.

All steel cylinders sold by XS Scuba come with our exclusive Lifetime Warranty against exterior corrosion issues.


~ XS Scuba

No worries. Wasn't wisdom, just searching to find something to respond to DH. I had seen somewhere that the 77s were not HDG, but as you noted, the website wasn't helpful. SB proved to have what we all needed.

 

[Hoosier]

Excellent! Thanks Rainer. It appears that both finishes are indeed outstanding. But I'm still very glad that I went with my hot-dipped HP100s.

A real issue is when the tank is rolling around and gets a plenty of scratches on an exterior over time, specially in the SALT water environment. I don't think it will matter on the fresh water though. HDG lasts long in any circumstances.