Derusting of (MX 7000) metal parts

[kitesurfer1404]

I did some experimentations with citric acid in the last days for rust removal. Had some rusty MX 7000 screws. See the results:





After that worked out quite well, I tried the same technique today with some motors from rotator lights and the base of the lights itself. This is one of the motors before and after:


(click to enlarge)


No joke. It's the same motor. Before I was not able to rotate it even with pliers. I thought it might go right to the trash. But, nothing to lose, I tried to remove and restore that thing. Worked quite well, as you see.


I submerged the hole unit into citric acid (for cleaning and chalky deposit), mixed in hot water and waited 5-10 minutes. Then I cleaned the motor under clear water with a brush. Heavier rust on the base-plate was removed with a "metal sponge" for pan and pot cleaning. Sprayed some WD40 on it and hooked it up to the power-supply. Working again!


After ~45 minutes "burn in" I stored it on the radiator to get rid of water, if there is any left.


Be careful with zinc coated or chromed parts! Aluminium doesn't like long treatments with acid, too.


I used a similar technique (with vinegar and salt) to remove the rust on this KL 6 by Hella some years ago: Hella - KL 6 auf www.kitesurfer1404.de








Hope this helps somebody someday.

 

[kitesurfer1404]

Made a mistake and posted the wrong pictures. Was talking about an intersection light and posted the rotator-images. Fixed.


Here are the images of the intersection light:

 

[shues]

Nice work! Thank you for sharing this with us.


I have moved your post into the Tips and Tricks forum, a more appropriate venue.

 

[rwo978]

Is the acid corrosive on skin? IE, need to take appropriate PPE measures before using? Also, you mentioned submerging the whole motor in? Is this correct? The innerds are fine? What is the mixing ratio and where do you find the citric acid?

 

[chief1562]

You mentioned citric acid. Where and what kind do I find this.


Thanks

 

[james23]

I Use white vinegar for smaller items jewelry and screws, I have filled a small container with the vinegar and let the items soak in it for a while. When the rust has dissolved, rinse the item off with hot water and dry it. When the rust was dissolved, I rinse it and wipe it down.

 

[kitesurfer1404]

Is the acid corrosive on skin? IE, need to take appropriate PPE measures before using? Also, you mentioned submerging the whole motor in? Is this correct? The innerds are fine? What is the mixing ratio and where do you find the citric acid?

I don't know, if it is *good* for skin. But I had no problem using it without gloves. My hands are still there.


Yes, correct. I submerged the whole motor. You have to wash it with a lot of clean water afterwards. And apply WD40, which flows in the darkest corner of the motor. But be careful not to spray it on the contacts!


Got the citric acid from the local supermarket. It is sold for cleaning/descaling coffeemachines. I don't know where to get that stuff in the US. Sorry. I bought the powder citric acid. Mixing ratio was "take this, rust!!" Just gave ~10-20 teaspoons per gallon, if I have to guess the amount in teaspoons.

I Use white vinegar for smaller items jewelry and screws, I have filled a small container with the vinegar and let the items soak in it for a while. When the rust has dissolved, rinse the item off with hot water and dry it. When the rust was dissolved, I rinse it and wipe it down.

Vinegar worked quite well on the Hella KL 6, too.

 

[mranum]

I realize this is an old thread but wanted to share something. One of my hobbies is woodworking, specifically woodworking with old hand tools. (Late 1800's to early 1900's) Generally I pick these tools up cheap and rusted. There are several methods for de-rusting tools, or anything steel for that matter. Citric acid is one way of course. I started out using white vinegar. Its very cheap, readily available, but the smell does get to you after a while especially if your doing it in the house. Another cheap and readily available thing to use is Alka-Seltzer.


But the best stuff I have found yet is Evapo Rust. You can get it at Autozone, Oreilly auto and I'm sure numerous other places. Comes in quarts or gallons. Not sure whats in it but it is not caustic and its perfectly safe to use. Truly amazing stuff and the best part is it never goes bad and you can keep on reusing it. I will just run it through a paint filter when it goes back in the jug. Pick some up you will not be disappointed.


Evapo-Rust Rust Remover Home


Here are a couple before and after pics of some tools I de-rusted, just to see how bad they can be and still bring them back. This was done with plain ole white vinegar. total soak time was between 8-12 hours with periodic brushing with a brass brush. You have to be careful with acids like this though as they will turn the metal black if left soaking for too long of a time.