Opinion on rust inside scuba tank

[nikolay_zhelev]

Hi fellows,

I would be very happy to hear your opinion on scuba tank rust visible on the attached photos below.

It’s a steel tank, Faber 12l long made in 2004, 232 bar working pressure.

I’m about to purchase it second hand and I would like to know if that’s safe.

All the best!

 

[Scared Silly]

Looks like surface rust from wet fill. I would give it a whipping to remove the rust then inspect. Initial guess it that it would pass inspection and be fine.

 

[rob.mwpropane]

Hi fellows,

I would be very happy to hear your opinion on scuba tank rust visible on the attached photos below.

It’s a steel tank, Faber 12l long made in 2004, 232 bar working pressure.

I’m about to purchase it second hand and I would like to know if that’s safe.

All the best!

I can't add anything, but pretty great pictures

What did you take them with? Is this 3/4" or 7/8"? (It looks like 3/4" to me)

 

[nikolay_zhelev]

I can't add anything, but pretty great pictures

What did you take them with? Is this 3/4" or 7/8"? (It looks like 3/4" to me)

Hi Rob,

I took the pictures with my phone I guess you’re asking about the neck tread - it’s M25x2.

To be honest the bottom worries me the most, because I can see cavities from corrosion.

Does anyone know the limits for cavities from corrosion for steel cylinder 4.2 mm wall thickness?

 

[GJC]

I was taught that pits on a steel tank had to be less than 33% of wall thickness. You need to look up the wall thickness from the manufacturer.

It looks to me like it should be OK after removing the rust, but you won't be able to measure pit depth until it is cleaned.

It probably has some rust under the neck too, which is hard to clean with a whip. You may want to get it tumbled to get it cleaned up.

 

[rob.mwpropane]

Courtesy of @grf88

O2-Safe Rust Inhibitor for Steel Tanks

So I'm planning on tumbling and cleaning my OMS/Faber LP85s. I've been looking at using rust inhibitor, but I don't really want to spend the $50+ and shipping to get a gallon of Compound O (Diethanolamine/DEA/DEOA). Looking for alternatives, I came across Evapo-Rust and also Cocamide DEA...

scubaboard.com

I'm not sure I'll ever go back to mechanical cleaning again.