There were messages a while back about the dangers of using acid to clean metal. The acid weakens the metal. I was thinking of using muriatic acid to clean some radiator hose clamps. Would the acid weaken them sufficiently that I should be concerned about them failing?
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Re: Muriatic Acid for Cleaning
I used dillute Muratic acid to clean the oxidation off my Whittek clamps and they came out great. I could not see any difference in metal thickness with the naked eye. I used about 30% acid and watched one real close as I kept track of the time. When it was done I did the rest using that time line( still watch closely). -
Re: Muriatic Acid for Cleaning
Chris
Muriatic acid can be your best and worse friend and as Dale says, it should be diluted. If you like, I can send you some pics of what it will do you for if it likes you and what it WILL do for you if it doesn't like you!
GregComment
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Re: Muriatic Acid for Cleaning
I use the readily available muratic acid. I think it's 30%. You can buy it at Home Depot or Wal-mart. Then I cut it 10-1 with water for something like hose clamps. Don't leave the clamps in too long, maybe thirty minutes or so.
Have a baking soda solution handy to rinse the parts in when you remove it from the acid. Otherwise, you'll get a haze of rust very quickly.
Like Greg said, it can be your friend or your enemy.Comment
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Re: Muriatic Acid for Cleaning
chris-----
Muriatic acid is an industrial quality, diluted form of hydrochloric acid. Hydrochloric acid is a very strong acid and acts very quickly to dissolve iron oxide and very quickly to dissolve ferrous metal period.
The concentration of acid and the temperature that you use it at will affect the amount of time that it takes for the acid to do what you want it to do. If you dilute the acid too much, it will still do the job, but it will take a lot longer to do it, especially if the solution is cold. What usually happens in this case is that you "decide to leave it in the solution for awhile". Then, you forget about it and you leave it in the solution for a lot longer than you intended to. That results in too much good metal being removed from the part.
I use muriatic at a lot stronger concentration. Maybe, diluted 4 to 1 (from the original 30% solution, which is a common concentration). It works very fast at this concentration. So, you "stay with" the part. You dip it for several seconds, then remove it. If you've got it all, you're done. If not, you dip it for several more seconds and repeat, as necessary.
You can also use a product called Jasco Metal Etch. This is a fairly concentrated solution of phosphoric acid. Phosphoric acid is a weak acid that works well at dissolving iron oxide. It's not so hard on the substrate ferrous metal parts, though, so you can leave the part in it for an extended period of time without risking damage. If you have time to clean a part, I think that the Jasco is the best way to go.
Products like Naval Jelly also contain phosphoric acid. However, I've found that the concentration is just too low to be effective in most cases. The Jasco is a LOT stronger and will be effective. However, you do need to use it at a concentration higher than the instructions say.
Whatever product you use, you have to rinse ALL of the acid off THOROUGHLY and QUICKLY after the part is clean. The acid will continue to dissolve the metal if it's left on the part---just because it's out of the solution does not "stop" the reaction. You can apply a neutralizing agent like baking soda (i.e. sodium bicarbonate), but this will, itself, form a film that will have to be rinsed off before painting. Bare cast iron will rust VERY rapidly after the acid or baking soda is rinsed off. For a part that's not going to be painted, but left "natural", you can spray it while still damp with a product like WD-40 or PreLube 6. These are moisture displacing compounds that will get under the moisture and coat the part with an "invisible" dry protectant (after the carrier solvent vaporizes). However, you have to remove them before painting. No problem here, though. Just wash the part down with brake cleaner, air dry and paint.In Appreciation of John HinckleyComment
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Re: Muriatic Acid for Cleaning
Well, this is what I didn't have sense enough to post. It's all accurate in my experience.Comment
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Re: Muriatic Acid for Cleaning
Acid etching can be very effective removing rust. For instance, the rear suspension parts of C2/C3's - the rear spindles, and caliper brackets, etc will typically be rusted/corroded since these parts came from the factory bare.
Yes, hydrochloric acid will work. However, it probably works to fast and you can damage parts. For me, I like to soak cast iron parts in Vinegar which is 95% water and 5% acetic acid. This is a gentle solution. Dunk your parts in pure vinegar and allow them to soak for hours or perhaps a day. I only let mine soak for a few hours since I didn't want to deteriorate the bearing races in the rear spindle forks. Once again acetic acid will, in time, do what hydrochloric acid will do, but the slowness of acetic acid allows you to be in control. Also, with acetic you can put your hands in the stuff without being concerned. Interesting...just place some clean cast iron in vinegar (acetic acid) and you'll soon see bubbles of hydrogen forming on the metal as the vinegar (acetic acid) is doing it's stuff. Also, when you check out at the market, the cashier will wonder why you are buying 5 gallons of vinegar.Comment
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