I found it on amazon for $84.50 + free shipping for a five gallon bucket. I bought two of them because on the directions it says to completely fill the tank. The reason I decided to try it is because it's reusable. I can find all kinds of rusty things to soak. It would probably be better and cheaper to take the tank off and have it boiled out but I don't want to have to paint the tank yet.
Again, as I asked above.... When the Evaporust has removed the rust from the walls/baffles of the tank, then what? How are you going to stop the bare metal from re-rusting again?
Also, another point that should be made. "Boiling out" a tank at the radiator shop is a comment that is often used, ....and I feel often misunderstood. While these days it is rare to still find a radiator shop that still uses a caustic tank, it is possible. Now here is where all of this is wrong.
First off, Sodium Hydroxide in their tank will generally be in a 10-15% solution. Sodium Hydroxide is great at removing anything that is organic ( i.e.: old gas, varnish, paint, old tank sealers, rubber, wood, leaves, etc. ) however it does nothing to steel. This is why you see it contained in a metal vat. If it truly dissolved rust, given some time (a few months) it would eat a hole thru the side of the vat too. As Tom mentioned above, it does however disolve soft metals given time. I have put engine blocks into my hot caustic tank without removing the rear seal and it would be partially dissolved when removed from the tank.
With that said about the soft metals, the tanks originally were a Terne-coated metal before they were stamped. This Terne coating was the rust preventer inside the tank. Hot caustic does dissolve the Terne coating. So when a tank comes back from a radiator shop after being hot tanked, folks look inside the tank and see shiny bare metal at the bottom of the tank and tell the rad. shop owner "Good job!". The issue is that most of the rust we find on tanks is on the top of the tank. This is an area you cannot see, and the hot caustic bath did nothing for that. If the rad. shop owner used a steam cleaner to flush the tank with, the pressure knocked off the loose particles & sediment however the metal is still bare inside. Guess what bare metal is going to do now?? So this brings me back to my question above, - How are you going to stop the bare metal from re-rusting again?
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