Inside of steel tanks black?

[Leadking]

Phosphate finishes as used by Faber and early painted cylinder from Worthington had a black colored finish. See https://en.wikipedia.org/wiki/Parkerizing

link to my post Sept 8, 2005 http://www.scubaboard.com/forums/ol...ington-cylinders-2.html?highlight=parkerizing

 

[BERGYMON]

My dive shop uses a rust retardant rinse after a visual. It leaves a black color. This is normal, if that rinse was used, afaik

 

[uncfnp]

My dive shop uses a rust retardant rinse after a visual. It leaves a black color. This is normal, if that rinse was used, afaik

I just picked up a set of newly O2 cleaned and inspected tanks from my LDS. He suggested next year that I might want to have the tanks treated with a solution he said would protect then but leave the tanks black inside. I asked if they would still be able to have PP fills. He assured me they would. Then I read this thread and wonder if it is the same stuff.

 

[moose_grunt]

But the weird thing is, it leaves a black residue on my finger if I rub it inside the tank. Still haven't taken them in to the shop for a tumble, but I've tried simple green and blue gold, hot water, and ceramic pellets, and still end up rubbing black off with my finger.

 

[halocline]

But the weird thing is, it leaves a black residue on my finger if I rub it inside the tank. Still haven't taken them in to the shop for a tumble, but I've tried simple green and blue gold, hot water, and ceramic pellets, and still end up rubbing black off with my finger.

If it was my tank I'd first try to clean it with a bottle brush or sandpaper whip, if that didn't work I'd go for a tumble.

 

[Eric Sedletzky]

Personally I'd forget about coatings, finishes, stains, treatments, or whatever the blacking is, or is called.
What's wrong with plain clean steel?
I have a few different whips and wire brushes on rods that I made to clean the sides and bottom of my tanks. When I look in I can see clean shiny steel. I can clearly see when they have a reddish haze, I can see everything. What's better than that?