Monday, May 20, 2019

Old De-Rusting Trick Works!

I was surprised.  Actually, floored is a better word.  But first, I have to do a Grandpa Simpson story for a while.

I ordered a lot of the metal for my new engine build last weekend and received all the pieces by last Friday.  The issue with buying small quantities of metals is like buying small quantities of radio parts or a couple of screws.  Their default is to sell you more than you need and then stick on rough shipping charges on top of that.  "Too much" is fine - to a point.  Everyone likes having some steel or aluminum pieces to have around for repairing things, or unexpected little projects; and in the words of Mae West, "too much of a good thing is wonderful".  We just always end up needing something like a one inch long piece of 3/16" diameter drill rod and the dealers want to sell you 36".  I'd be happy to get 12".  It's still more than I should need, but not excessively.  I was able to get about a dozen pieces of various things like that from a place I'd heard of, but never shopped at, Hobby Metal Kits.  Fair prices, $10 flat shipping.

The flywheel finished dimensions are 3.750" diameter, and 1.125 thick at the hub.  Like this:

Note that it says the material is either cast iron or cold rolled steel (CRS).  So off I went to the metals dealers to find a piece of CRS that could yield this.  Some shopping around, first at Online Metals and then on eBay, resulted in me finding that a 4" diameter by 2" long piece was going to cost about $55 with shipping.  Then I stumbled across an eBay seller selling a slightly smaller piece, 3-3/4 by 1-3/4, but saying it was D2 Tool Steel.  His price was $18.75, including shipping.  I figured that the important part was that flywheel has a density more like steel or iron than aluminum and the alloy doesn't really matter.  I took what's probably a better piece of steel for many uses at almost a third of the price as the 1018 CRS.

When I received the package, there was a 5 lb 10 oz hunk of rust in the box.  That's an exaggeration, but not much of one.  There wasn't a single spot on the disk that wasn't rusty.

The thing is, the rust probably isn't an issue.  I'm going to skim the diameter of the disk down a little and take off much of its length, and if it's just superficial rust, it'll be in my shop vac within minutes of starting.

Over the years, I've read many "how to fix rusted tools" articles that involved soaking the tool in a bath of vinegar with added salt.  (Here's a more in-depth source.)  One of the voices in my head suggested I try this, just to see if it works.  It was such an impulse decision that I didn't even take a "Before" picture.  It was in a plastic leftover storage tub, covered with vinegar by about noon Friday.   Naturally, I went by and looked into the clear tub a few times, but the vinegar went nearly black as the day progressed, so something was going on in there.  Saturday afternoon I took it out, gave it a light brushing with a Brillo pad and was shocked to find it looked like steel.  It looked etched with a matte gray finish, but with the exception of some black marks that I could probably scrub away the rust was gone.

This disk was the solid reddish-brown characteristic of rust, with a fair amount of black in the color, too.

Rust comes up as an issue all the time.  I'm sure we get more of it here with our humidity and salty sea breezes, but it's an issue in most places.  I can't tell you how many times I've come across this idea but dismissed it.  I waited until now to try it and it actually works.  I may be the only guy in America who dismissed the idea of soaking files or pliers or other tools in vinegar to de-rust them, but I doubt it.  Give it a try.

Edit 5/20 2147 EDT:  The bad writing fairy snuck in between editing and posting


  1. You will probably want to adjust the feeds and speeds with D-2, it has a high chromium content and is notoriously hard on high speed tools. Carbide helps, but you still have to slow rpms or it can work harden on you. Best of luck!

    1. Thanks for that!

      I have carbide tooling for all my lathe tools now, brazed or the the kind with replaceable inserts, but I sure want to finish with the same number of tools as I start with.

  2. I have been a mechanic for forty five years now and had never heard of this up until a couple of years ago on someones Blog. Of course I had to try it and my goodness was I amazed!
    Rusty vintage tools , files, parts, anything ferrous that can be submerged. I did find that leaving stuff in too long isn't good and you really ned to rinse and wipe everuthing off well and then apply some kind of light oil to keep it from rerusting immediately.
    I have also founf that Apple Cider Vinegar works better than White Vinegar.
    Rlated to this sbject, I just started using the Evaporust product and am amazed yet again. It works the sam way, by submerging or keepng the parts wet by wrapping with something and keepng it wet. It is non toxice and best of all, can be filtered and reused.

    On an unrelated note, I belong to a mini lathe group on Yahoo and someone just posted this video abut a tool a genius came up with, more of a tool system actually, that allows you to turn radii and a complete ball even on a small lathe, by hand.
    This thing is absolutely amazing. I immediately thought of you, it may or may not be something you would be interested in but there is no denying this thing is absolutely ingenious.
    It's called the Turnado and if you have never heard of it you will definitely want to see this video just to marvel at the guy's ingenuity if nothing else. I have no idea what the thing costs but it looks expensive, still worth your time to see though.

    1. Cool idea. A few days ago, I ran into this guy's idea for a powered cutter that cuts spheres. It's not as flexible as his Turnado, but you can see the similarity.

      I have a set of small hand turning tools and a rest for the Sherline lathe. It's intended for turning wood, but it's the exact same principle as the watchmaker's lathe and gravers.

    2. It seems like this is a good place to ask, how to free up an aluminum thread nut from a steel threaded bolt? It's my dad's Korea-era USMC entrenching tool.


    3. A 50/50 mixture of automatic transmission fluid and acetone is the best penetrating oil you can get. Unfortunately, the two ingredients separate from each other rather quickly and the acetone evaporates fast. If it were me, I would soak it in diesel for at least a week. It takes longer but diesel is also an excellent penetrant. Marvel's Mystery Oil also works real well on aluminum. Your problem is the aluminum has corroded onto the steel and slow and easy is absolutely your best strategy.
      Good luck!

    4. Thanks for answering that, Phil, because it's better than I could have done!

    5. my pleasure,I would hate to see something with so much sentimental value get damaged.

  3. Excuse the typo's. Some of the keys on this laptop are giving me trouble and sometimes I don't edit things too much.

  4. One of the machine rebuild sites I read has raided his local pawn shops for tools, finding all sorts of neat 50cent finds. Rusted, caked, gunked up.

    Takes them home, tosses them in vinegar for a while and then to his parts washer. Excessively bag gunked up stuff gets saved for being blasted by his diesel-burner hot-water pressure-washer, and then treated. As Phil says, after you de-rust, no matter what method you use, vinegar or derust solution or electrolysis using baking soda and a trickle charger, once you clean off the surface schmutz of the derusted part, wiping down with oil or wax or some sealant material is necessary.

    He's found stuff that looked like a dog's breakfast that, cleaned up, now resides in his main tool box. And the other stuff is in his 'go to junk yard' toolbox.

    Makes me want to attack my tool box and see what I can revive.

  5. Hi SiG, I don't really mean to Blogwhore here but it is related to the subject and I thought you might be interested.
    I just did review of that EvapOrust stuff over at my place complete with before and after pictures and thought you might want to see what you think in case you have never tried it before.