Behr Concrete Etcher & Rust Remover

i just bought some "Behr Concrete Etcher & Rust Remover" to clean out my gas tank. how long should i let it sit in the tank? also the instructions call for a wet surface, should i water the tank down before hand?


Re: Behr Concrete Etcher & Rust Remover

the stuff is already "watered down" .. it's just water with lots of phosphoric acid in it, a major component in commercial rust removers.

Phosphoric acid attacks rust quickly but attacks good solid metal only slowly, so time is not critical..

First clean the tank with soap and water .. The acid cannot penetrate an oil coating.. so the tank has to be clean inside.


Mix it 50/50 with water and leave it in the tank overnight and see if that does the trick... If not leave it in there another day.

Then dump it out (save it, it's still got power) and neutralize the acid residue with a couple tablespoons of baking soda in a tank of clean water. When it stops bubbling, that's done.

Drain and dry the tank thoroughly in the sun.. or with forced hot air.

Re: Behr Concrete Etcher & Rust Remover

Like with a hair dryer?Mister Wizard Golly Gee Wilickers lol Dan

Re: Behr Concrete Etcher & Rust Remover

thanks a lot!

Re: Behr Concrete Etcher & Rust Remover

I wouldn't used forced hot air--used a hair dryer to dry out the tank of my Newport and it re-rusted immediately.

Just shake out as much water as you possibly can, then spray it down with WD-40 and put some drygas in the first tank of gas.

That's what I did about 4 months ago, and haven't had any problems.

Re: Behr Concrete Etcher & Rust Remover

you're probably right about that .. a quick WD40 coating can't hurt (unless the next step is application of a tank-coating like Kreem).

Whenever i've used paint-prep (basically phosphoric acid) on bare steel, the steel rusts immediately if it's allowed time to dry on it's own. The acid etch is a truely ideal surface for rust formation.

Aside from how it's done, tanks will retain a lot of water even if the petcock is removed .. mine holds about 3 or 4 ounces that cannot drain past the petcocks threaded boss since it extends slightly into the tank...

That's a lot of water. Do something to get it all out before throwing fresh fuel mix in there.

Re: Behr Concrete Etcher & Rust Remover

Tim Phillips /

I used Behrs concrete etcher on my tank that was real rusty. Poured it in full strength and left it for 2 days. After I dumped it out I rinsed it real well with water and put in a full bottle of dry gas. I shook that around and dumped it out and then put in the gas/oil mixture. The tank looked like new when i was done. Hope this helps-


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