Sand blasting the outside of old steel 72 tank good idea / bad idea?

[lowviz]

...//... Hot dipped galvanized is timeless, paint is.... well, it's paint.

Pete

So sadly true.

Working on a cold electrolytic process. Have an old soldier that is taking on scary reddish patches. I will prevail. Synchrowave DC welder, GalvOver (TM) and calcuim chloride pool chemicals. Getting close.

Used to work at Xerox, embrace no environmental impact.

 

[DA Aquamaster]

Let me repeat this again - due to the temps involved and possible impact on the metal and it's heat treatment, getting your tank hot dipped will result in it being condemned as hot dip galvanizing is not allowed on any high pressure tank once it's been initially qualified.

 

[lowviz]

Let me repeat this again - due to the temps involved and possible impact on the metal and it's heat treatment, getting your tank hot dipped will result in it being condemned as hot dip galvanizing is not allowed on any high pressure tank once it's been initially qualified.

Room temperature electrolytic deposition is the only way to go.

Took me a minute to understand your concern. No, not typical GalvOver use. Just as a consumable electrode in solution.

 

[minimalistdiver]

Here is what I went with:
Sand blast in my cabinet
Rustoleum Cold Galvanizing paint from Home Depot
Very lightly sand and paint Duplicolor BQ910 Gray Primer Surfacer.
Rattle Can paint over the top of that.
Rattle can clear coat
Watch every year for any rust bubbles and gashes. Sand and touch up as needed.

 

[lowviz]

Here is as far as I got:

Ran some beads so that it was more "real world" coverage than just a polished steel plate. GalvOver on the ground clamp, calcium chloride in solution, got lots of real zinc, but poor adhesion. Easy to wire brush off. Any electroplaters out there?

We could share the spoils of success...

View attachment 131138

 

[captain]

To be specific it is ZRC Galvilite. "ROLL" on not spray 3 coats using a foam roller. I would argure that it is superior to any other type of coating for use on steel tanks other than hot dip galvanize. It needs to be applied to bare steel. Putting on top of paint will not work to provide any galvanic protection. Believe me I found out many years ago this is the best after trying the various two part paints. If you must have a color you can top coat it.

ZRC - ZRC Galvilite Galvanizing Repair Compound

 

[muddiver]

Ok, here's a twist on the renovation possibilities: Buy some flat zinc anodes (either small boat prop anodes or one of the Kirby Morgan commercial diving helmet kits) and strap them aginst the cylinder with a stainless steel hose (or plumbing) clamp after sand blating. Then coat the whole assembly with what ever primer, zinc-rich primer or paint you want to use. Remember to tighten the straps holding the anodes in place periodically the make up for the loss of anode material over time. Once the anodes get down to, oh say, 50% their original size, replace and continue to dive. The only thing you really have to pay close attention to is the contact area between the zinc and the cylinder wall has to be tight and continuious to provide a good electrolytic bond.

As a matter of fact, a good way to get that bond would be to form/cast a small zinc ring around the neck of the cylinder.

 

[cool_hardware52]

Independent of the possible heat issues, getting tanks hot dipped is next to impossible. Tanks are buoyant, very very buoyant when the density of molten zinc is considered. Dipping tanks requires special racks that can force the cylinders under the surface.

When any sort of hollow fabricated steel items are to be galvanized they have to be provided with vent / drain holes so they can sink into the acid bath that precedes the zinc bath and into the zinc bath.

Virtually impossible to find an independent galvanizer that will do tanks.

The next best solution is flame sprayed zinc. This process does not heat the tank, bonds well and has provided me with very good service on many steel tanks.

It does leave the tank with a rough ~100 grit surface, but this can be burnished down with a hardened steel dowel to reasonably smooth.

Tobin

 

[JohnB47]

The next best solution is flame sprayed zinc. This process does not heat the tank, bonds well and has provided me with very good service on many steel tanks.

It does leave the tank with a rough ~100 grit surface, but this can be burnished down with a hardened steel dowel to reasonably smooth.

Tobin

Where do you get flame spraying done?