Swimming Pool Acid as Rust Remover

[Gray_Cat]

I tried searching for this topic with no luck so am asking the question:
Anyone have experience using swimming pool acid as a rust remover/inhibitor?
If so, did you dilute it with water? If so, by how much? Dilute with alcohol?
How did you neutralize it? If using just plain water, did you have flash rust problems? Anyone use Pot Ash?
Many thanks for any and all information!
Roy

 

[Jim_Gruber]

I do know I used some muriatic acid on a boat trailer this summer prior to painting. I neutralized with water immediately and painted within a day. I did experience flash rust problems but nothing like I'd been having. I should note this is a galvanized trailer that I annually clean the bottom of the boat with muriatic acid applied with a tank sprayer to remove the green slime. Portions of the galvanized trailer were surface rusting due to the exposure to I'll assume muriatic acid. Trailer was roller painted immediately with silver Rustoleum and is now in indoor winter storage. Will be curious to see what if any rust reappears after 6 months of dry indoor storage and again after spring/summer months of exposure to the elements.

I do know that using the electrolytic method of rust removal will usually give superior controlled results. Method involves washing soda, battery charger, sacrifical anode, and a method for immersing the rusty part under soda.water mixture. Scrubbing immediately with brasso copper wool pads will prevent flash rusting.

Search the wiki for Electrolytic Rust Removal or google the same for details.

 

[JPSmit]

do not inhale muriatic acid

 

[texas_bugeye]

You can treat metal with a phosphoric acid metal wash, a solution of Phosphoric Acid and alcohol before painting. It will leave a protective coat of iron phosphate. use some rubber gloves and scotch brite pads to remove lite rust and grease oils and such. Muriatic is some pretty harsh stuff and the metal will flash rust before your eyes.I would do a little research before using any acid.Phosphoric will bit if you get any on you but muratic will sirously burn you.

 

[JamesWilson]

You can treat metal with a phosphoric acid metal wash, a solution of Phosphoric Acid and alcohol before painting. It will leave a protective coat of iron phosphate. use some rubber gloves and scotch brite pads to remove lite rust and grease oils and such. Muriatic is some pretty harsh stuff and the metal will flash rust before your eyes.I would do a little research before using any acid.Phosphoric will bit if you get any on you but muratic will sirously burn you.

I used a commercially available rust "dissolver" solution that seems to have worked well so far. Treat, then rinse thoroughly, dry well, and prime.

 

[bill_young]

Just a coincedence I suppose but this subject also popped up today on another board. This is an interesting solution: https://www.mgexperience.net/phorum/read.php?1,992966

 

[dklawson]

The electrolysis method described in the link above does work. I've played with it a few times. However, it has exactly the same problem as electroplating. You get preferential attack on corner areas and it's difficult to do anything to the interior of a part unless you make an electrode to go "inside" the part you're trying to clean. Still, it's worth experimenting with. Coincidentally, the electrolyte used in this process is also a pool chemical (sodium carbonate? NOT sodium-bicarbonate like baking soda).

I use phosphoric acid for all my paint prep work. You can use name brand stuff from body-shop/paint suppliers, or you can buy different brands of "generic" stuff. I typically buy a gallon at a time from a local agricultural supply store. To use it, you need to thoroughly degrease the part first as it will not cut through grease, oil, or dirt. Keep the surface wet until a uniform, dark grey color appears. Do not let the surface dry as it will leave a chalky white deposit behind that is not good for paint adhesion. Once the dark grey coating is achieved, rinse the surface with clean water then immediately towel and blow dry. Any flash rust that appears can be wiped off with prep solvent just prior to painting. You do not neutralize the surface apart from the clean water rinse.

 

[Whitephrog]

For smaller parts Evapo-Rust work very well.

 

[Gray_Cat]

Many thanks everyone for the responses. I am planning on using the electrolysis method on smaller parts I have removed from the car and will use the phosphoric acid method on the body. This is great info and I'm certain very useful to others.
Thanks again!
Roy

 

[TexasSprite]

It may be the climate here in Texas, but if I keep even an unopened bottle of muratic in the garage or shop, any iron/steel object exposed to the air in the shop will grow rust like crazy.