What's the best way to clean up a VERY rust covered water table?

[Mr Yuk]

So I recently became a high school welding instructor and am fortunate enough to have a Torchmate 4x4 table in my new shop. Unfortunately, the previous instructor didn't do much maintenance on it. As far as I can tell, they just used water instead of using an additive, didn't clean it at any point, and let the students quench their freshly welded coupons in the less frequently used side. Some students simply left their coupons in there instead so that combined with all of the bits of metal from using the table as it was intended for years has left me with a mess that I need to clean up.

With a little elbow grease, I removed some of the rust from the floor of the table. It looks like it's painted or is coated with something so I don't think it will need much work... at least until I get it cleaned up and see if there is damage underneath. It would make sense that the sidewalls and grate holders would be painted/coated if the floor is. The rust on the sidewalls is pretty caked on so even using a rust removing gel may not be enough.

Looking around online I've found suggestions of using vinegar and baking soda to remove the rust and that seems like the cheapest option, but will it damage the coating? Will it even work to break down the caked-on stuff on the sidewalls? Other products such as Evapo-Rust, Metal Rescue, etc. look like they would work, but filling the whole table with them would be a bit too expensive. Could I dilute them with water to cut costs and have them still be effective?

What would the fine people of Plasma Spider suggest my next steps should be?


Here's what it looked like after I started to clear it out



Here's it is almost completely cleared out

[SegoMan DeSigns]

Looking good, you could wire wheel the remaining areas if you want a cleaner look, then run rust additive to prevent future rust. I use laundry soda, 3 boxes will treat 350 gals and put the PH up to ten.

[acourtjester]

the former shop teacher should be shot, as an instructor he should teach good habits not lazy ones. After cleaning as you have done I would use rustoleum paint with a hardener added to protect the tank from rusting again. Then use a solution as SegoMan points out.
There are recipes for the rustoleum mixture online basic 3 ingredients it will last a long time.

[thejaydog]

PLEASE, do not paint that tank. This is part of the grounding, especially the center spine use a wire wheel, then then using vinegar soaked rags to coat the slats and interior table. This will help restore the table...then use a biodegradable additive (plateguard) to control rust and reduce algae bloom

[djreiswig]

The work lead from the plasma cutter should be attached directly to the material and not the water pan, so you don't have to worry about "grounding".

[TJS]

Sorry, but the washing soda stuff does work if you want a white fuzzy growing residue everywhere. I think the commercial plasma quench solution does not do this. I have yet to try it after my clean out. I am holding off cause I want to make a new water table.

[SegoMan DeSigns]

Price out for the commercial plasma quench for 350 gallons and get back with me.. If you don't like the white stuff put cleaning the table on your weekly "Maintenance List" along with your linear rails that look a tad rusty.. There is also several different recipes posted on this forum for alternative anti-rust additives. Painting does not work well if you do dry cuts on Aluminum or other materials. The only time I use a ground / work cable is if the metal is painted or extremely rusty then I buff a spot and use the magnetic clamp on it.