How to handle mysterious tank coating?

[Luis H]

Captain is correct.

There is not code or any requirement to remove the internal coatings.
CGA recommends careful inspection of lined cylinders, but there are no requirements to remove the liner if no evidence of rust is visible.

This is also covered on page 32 of the PSI “Inspecting Cylinders” book.



Added:
Rust takes about 10 times the volume of steel (this is a very rough approximation); therefore most coatings will blister if there is any rust under them. Only if it is a very thick coating (like some of the external tank coatings) can rust form without showing very clear signs.

 

[NorthWoodsDiver]

Well yes the coating is blistered looking but not large patches or anything that made me think its going to be overly rusted. I love 72's, they are my favorite tanks along with aluminum 40's and LP104's but thats besides the point.

I know the fumes created from acetone or MEK are harsh but I thought maybe that or some acid would help cut the coating before a thorough tumbling. thoughts?

 

[Bob3]

FredT had a fairly detailed posting on how to best go about removing linings, though for your purposes either a whip or a stiff wire brush could be used on the blistered spots so you can tell right away if there is enough pitting under the blisters to fail the tank.
Global Mfg. Corp.
use the search box & input "brush" and "tank whip" to eyeball the goodies.