neutralizing muriatic acid

The guys at the radiator shop where I had my fuel tank cleaned/coated told me to use muriatic acid to clean all the small parts (fuel pump & fuel level sending unit). That worked great, except that those parts rusted immediately afterwards, and now they look much worse than they did before. After reading a little bit online about muriatic acid, I understand why this happened. But now I need to clean these parts again, and I'm wondering what I should do to neutralize the muriatic acid afterwards. These parts are going into my fuel tank, so I can't paint them, and I'd rather not have to spend any more money at the radiator shop having these parts coated. Any suggestions?

I would use baking soda.
http://en.wikipedia.org/wiki/Acid–base_reaction

Rinse them off with wter and dry them. Then drop them in a bucket of diesel fuel or oil.

Do I need to start a poll?

1) baking soda (in water?)
2) diesel
3) oil

jesusgatos said:

Do I need to start a poll?

1) baking soda (in water?)
2) diesel
3) oil

Click to expand...

I vote none of the above.

Remove the parts from the acid bath then immerse them into either magnesium or zinc phosphate solution. Once they stop fizzing, rinse in water, the oil them down.

No more rust and a good protective coating.

Hmmm, where would I be able to purchase magnesium or zinc phosphate?

Baking soda in water will neutralize the acid immediately and is safe for your parts. The best course of action is to then coat the parts in diesel or oil. Thats how we do it.

use baking soda, its caustic and will neutralize the acid, wash off with clean water and install as soon as its dry

jesusgatos said:

Hmmm, where would I be able to purchase magnesium or zinc phosphate?

Click to expand...

MidwayUsa. it's called parkerizing solution.

Lauer Manganese Phosphate Parkerizing Solution 16 oz Liquid - MidwayUSA

We use muriatic acid at work to remove blueing from steel. We just use a water and baking soda mixture to rinse off the parts than rub them down with oil after they have dried. Seems to work fine.

Hopefully you water down (deluted) your solution before you ecthed everything that might explain the aggasiveness of the rusting

No, I used it full-strength...

As far as baking soda goes, I'm guessing that I should dilute that in water? Yes? How much?

Full strength Muratic acid will also remove good metal in addition to the rust, it's very aggressive. I use soda ash to neutralize any acid I use, it's available at swimming pool suppliers. It's used to adjust the PH in pools, to raise it. Takes a lot less than bicarb to do the same job.

Thanks guys. I used the muriatic acid again, then neutralized it with baking soda, and then dunked all the parts in motor-oil. Parts look great. I'll know in a few days whether or not they rust again...

Good job! Cheap, easy, and effective