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In the 3D printing world this got posted today..

http://www.thingiverse.com/thing:971667

I looked at the pictures. Seems to work really well.

-jim lee

I need one of those big enough to put my M in

unless it only works on pipe wrenches

We set up a bath in the Shop last year to see if it worked as well as on youtube. It did! Just make sure you paint or coat your parts quickly or they'll get surface rust NOW.

I was warned about using it on high stress parts due to hydrogen embrittlement, but can't speak to the accuracy of that warning. A friend told me of a guy who did a set of wire wheels. I guess the spokes failed and the electrolysis process was blamed.

acid works good too, i used about 1/2 gallon water to 1/2 cup or less acid, and let it soak a few hours, then scrubbed the rust off while rinsing in warm or hot water. came out bare metal without removing any of the non-rusted metal. could probably do a bit of research and find out what the ideal ratio of acid/water is. just be sure to soak in plain water afterwards to make sure all the acid is gone

Isaac; what kind of acid?

Yes, and molarity would be nice to know too.

-jim lee

hydrochloric acid (also commonly called muriatic acid) and around 18-20% acid, and 20 minutes to an hour. the process is called pickling.

the fumes from the acid are very strong, so it's best to do it in a very well ventilated area, or outside. for small stuff, a plastic coffee can works well, cause it has a large lid which you can put back on it, this will prevent much evaporation from happening. At school, we use a 40 gallon plastic salvage drum, so the entire lid can be screwed on and off. any steel tools left near an open container of acid will develop rust in a short amount of time, so always keep your acid tightly capped and stored away from things you don't want rusting.

you'll want to lightly oil the steel after pickling, removing the rust, and washing in water, or it will rust within a few hours. rinsing with baking soda/water will help reduce rusting, but won't prevent it entirely.

Thank you.

Hi Guys,

Yeah, the Muriatic acid works very well, but the warnings need to be seriously heeded. Always add acid to water, not the other way around. I know....we've all heard it, but how many of us have actually followed the directions? The issue here is when you add water to acid you begin a heat releasing chemical reaction......that's "Exothermic" for Jimbo. That means the acid could begin to boil and start shooting all over the place.......bad, very bad. As for the fumes.....you CAN'T breath them in.......your lungs will instantly paralyze when the acid fumes hit them......meaning you won't be able to inhale or exhale......really bad feeling, trust me. Lastly......protective clothing and eyewear are a must. You might be a tough guy and shrug off metal filings in your eye, or hot embers from the cutting torch going down your shirt, but you won't shrug off acid in your eyes, because when you do finally shrug off the pain and can open your eyes again you won't be able to see........ever. If you wear contacts the acid will melt the contacts right to your eyeballs. Another really nasty feeling.

The other dumb mistake people make is the "more is better" thing. I did this, as well as most of the other bad things I just discussed, so start with a small amount of acid and then build it up to reduce the reaction time. I went from a few glugs out of the bottle mixed with 5 gallons of water to using it straight without mixing it with water. Big mistake. I put some rusty M37 bolts in the bucket to de-rust....came back 20 minutes later and the bolts were literally GONE. Lesson learned.......if you leave metal in Muriatic acid too long the acid dissolves the unrusted metal as well. Lastly, keep a big box of Arm & Hammer baking soda and a turned on garden hose within arms reach at all times........to neutralize the acid in a hurry if need be and wash it off your skin and out of your eyes.

Now have a safe and fun time playing with the acid!

regards
bob

yep! gotta be careful with this stuff. and like i said, it will eat your tools. and your skin and clothes if you get any on you.
the pickling tank at school is located right next to a big sink, so it's easy to wash parts, or yourself, after contact with acid. I will look tonight and see what concentration the "full strength" stuff i have is. maximum purity is around 32% but i'm pretty sure this is quite a bit lower than that. i will take a look and report it if i remember (:

Was watching some car show and they were showing some ph neutral stuff that dialoged rust with no range to the base metal and was harmless to you if you splashed it on you. They had a frame on jack stands with a shower curtain understand it. A sump full of the product with a pump, hose and shower head. It was left to spray over the frame over night. In the morning, it was rust free.

Hi Just,

I've seen that done with Evapo-Rust and other similar environmentally safe rust removers. There's even a video on Youtube of a guy who restored a Boss 302 that way........by letting the liquid flow over the hard to reach rusted areas of the body, then drain into a pool and be pumped back over the body. You just need a lot of the liquid, and it gets pricey at $25 to$35 a gallon. But it is safe, for sure.

later,
bob

Took a peak at my master cylinder, I only rinsed it in water and lightly oiled it after the acid. Should have soaked in baking soda, and oiled heavily. It's got fresh rust showing through already. But I'm not gonna worry about it now cause it needs a new one badly