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Restoring metal parts with Muriatic Acid.

Just curious, Mr Gorsky, if you've tried the muratic acid mix on anything that has electrical connections on it?

I'm thinking about the steel turn signal housings for example...mainly the soldered wire ends in bulb sockets. Think the acid would leave the solder alone? Still fooling with it, but tried the cider vinegar bit on them (lol, 2 days), and after looking fairly good. After, a water dip, tossed into my kerosene tank, pulled to dry, and watched rust coating again.
Prob right now, is it seems still some rust behind the socket 'plastic' spring-loaded contact plate. Messing with it, but won't push in far enough to get a bulb into the socket.

I've dealt with muratic acid plenty of times in the past, usually stronger than your mix. Know it doesn't hurt plastic, or the like, but not sure on solder, copper, brass, etc. (Used to clean my engine blocks with a 50/50 mix, for the water jackets.)

Any ideas?

Solder is 60% tin and 40% lead. Both of these metals react with diluted hydrochloric acid, but very slowly. I've had some solder in the mix for an hour now with no obvious effect. Doesn't react with copper, but will with brass....so you can use it to clean up brass.

I've got similar issues with my bulb sockets, but I've got them all working at the moment. When the time comes, I'll replace them with $3 items from RockAuto...check them out.
 
Appreciate that, Mr Gorsky.

Don't know for sure, but in my past using the acid on steel parts, I'd mix a neutralizing solution of water/soda ash, too.
Anyway, back to the grindstone...(had to put the one signal housing away, before I broke something.)

- - - Updated - - -

On your cleaned bare steel parts, how are you finishing them off? Any prob with re-rusting?
 
^^^My pleasure.

None of the stuff has shown any signs of rust yet, it's only coated with a little WD40. In the fullness of time I'll likely chase up some RPM. http://www.ecsautomotive.com/rpm.php

The latest into the mix....air-conditioning condenser brackets.

Before:
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....and after:


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^^^^^These cleaned up really quickly, in less than forty five minutes. Then a quick coat of rattle can etch primer, and some flat black. Better than OEM :):



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Thanks Gorsky. I'm gonna try it in the future.

As for others concern over the safety of it, I get it, and thanks for the alternatives. I'm confidant anyone wrenching on this site has gear head skills, and trust them way more than I would John Q public at Wallmart buying it for his pool.

Looks like Gorsky's results here speak for themselves.
 
Thank you gents, it's been a lot of fun cleaning up this stuff and it's making a big difference under the hood. I think posting the before and after pics really helps....we're all visual people.

Here's a bunch of clips and fasteners used to secure the air-cond lines. These were really difficult to get cleaned up. I'd drop them in for an hour, get them out, rinse and wipe them down, then immerse them again. No bolts in the after pic, they cleaned up really quickly and I forgot to include them when I took the pic. The worst clamps took about seven hours to get right-ish, the corrosion was pretty bad:


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aircond1.jpg

 
Very good info here ... what does it do, if anything, to grease? Looks like one of those clamps had a little grease in the before picture.
 
This might help, tallhair. From experiance, grease and paint will block the acid from the steel. Parts need to be clean of oil, or grease.

The paint bit, had a bracket that still had some paint on places, with rust under the paint that the acid did not take off.
 
Hood latch

How would you suggest cleaning up a hood latch?
I am a little concerned that acid might harm the internals
and blasting might lock up the internals

This is an example of a cleaned up one
mystery_hood_latch_1.jpg
 
Guys Chemistry is my business. Muriatic Acid which is generic for Hydrochloric works by creating heat in the presence of Iron, calcium and Magnesium. A very fast product that remove these minerals and oxides quickly. TAhe down side is Hydrochluric causes severe damage to all non ferrous metals. If you are willing to few a few hours for even better results without the damage done use Phosphoric acid or citric acid. to provide the desired results. No damage will occur. if your willing to wait a few days then get a 5 gallon bucket of Molasses and mixed 1:4 with water. Thie chemical reaction is to make Phosphoric acid and it can be legally dumped down drain after with no effects.
 
Thanks snakeoil. I've used the muriatic acid over the decades. It's very dangerous....and the vapors can wreak havoc on you, in no time. I no longer use it. I'll pay to have stuff done.
 
Guys Chemistry is my business. Muriatic Acid which is generic for Hydrochloric works by creating heat in the presence of Iron, calcium and Magnesium. A very fast product that remove these minerals and oxides quickly. The down side is Hydrochloric causes severe damage to all non ferrous metals....

Didn't react with tin/lead solder. Doesn't do anything to copper....what non ferrous metals are we talking about here?

Bear in mind that old Mopars are 80% steel, 10% rubber and 10% vinyl :)
 
I tried the vinagar for rust removal. It did pretty good. I did a cast iron intake. I can't find a before pic but it was rusty on the inside and that's why I wanted to try an acid. Dollar store for 4 gal. Walmart for a plastic tub. Used baking soda for a neutral bath.
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Back in chemistry class freshman year in college, i had some fun with concentrated hydrochloric on a rusty old rat tail file. Immediately started reacting pretty violently with heat and 'smoke', even though i only used a few drops. The upside - in about 3 seconds that rat tail file was good as new.

Yeah the fumes are tough, but used in a well ventilated area you should be good. As noted above, the good thing is that it quickly reacts with the rust, the problem is that it also reacts with the iron beneath that rust. When reacting with iron, it obviously starts damaging the surface. However, not so obviously, it creates hydrogen gas which is explosive.

Still, I'd have no problem using it on a big bulky part like a bracket, but I'd avoid it for sheetmetal or light housings, etc.

Most masks can't deal with that sort of fume, so I'd use it outside and use a fan even if there was no breeze.
 
To correct myself it is damaging to steel, not lead or tin.

Nope, and every pic I've posted here will attest to that. It reacts with steel (and that's why it works). I only use a 10-20% concentrate, so that limits the reaction. At the most, I see a tiny film of bubbles form on the metal after immersion. Mostly I see nothing happening and I'm surprised at how the rust disappears with so little fanfare.

As mentioned earlier, I ONLY use it outside (to avoid corrosion forming on anything else in my workshop)....and I've never had any issues at all regarding fumes.

Lock up the dog, keep the kids away....works great.


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Mr. Gorsky, I don't doubt the effectiveness. Hydro causes damage to steel. The speed of Phosphoric is very slow but does not cause permanent damage to Steel. Your using a dilution of maybe 9 percent Hydro diluted. Rare to find 20-30 percent Hydro in consumer market place because of severe fuming without buffering. Please continue to use what you like but avoid telling others how great it is considering the danger it represents to health and metals. The reaction is to the presence of Iron "rust" calcium or Magnesium.
 
The fine intelligent members here can make their own decisions. Most of the members on this board own guns. I prefer having strong acid around the house....much safer.

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