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So I have a TON of old steel tirods that have just accumulated in the tool box (usually upgraded to titanium). I read some thread (of course I forgot to save it) about cleaning and then doing a heat and an oil quench. So of course I went off to youtube to watch some videos.

I removed a bunch of rust from these by soaking them (and some old pinion gears) in apple cider vinegar for about 18hrs. They cleaned up pretty nice and then I put them in a bath of baking soda and washed them off and dried them. I watched people heat them up and drop them in oil to get that nice black finish back. Questions are:

1) doesn't quenching like that make them more brittle?
2) how tough is that finish?

I saw some say to use dirty old motor oil to get a blacker finish. I saw other folks then reheat and then let air cool to help it re-trap the carbon and increase strength. Just looking for good ways to cleanup/restore/improve(?) those original tirods.

quenching won't make them brittle, as they are mild steel. realistically, you are just heating them up so they oxidize and the oil you put them in cokes up and combines with the oxidation quickly.

I've never tried it, so that's all I can add. I just put them in a phosphoric acid cleaner so they get iron phosphate gray/black coating on them. its not very tough though.

Quenching them in dirty motor oil does not really work well. If you want them to be coated and not rust as easy put them in a pan of boiled lindseed oil (get at lowes/home depot). Brush the oil on the parts and use a disposable aluminum broiler pan to bake in the oven for 3+ hours at 250. You may want to do this more than once. Let them cool down on their own, do not quench in water. This is an old time machinist finish. I have some tools from the 1940s that were treated this way and have not rusted even here in Florida. And no I did not buy them new, the old stuff is just built better. Hope this helps.

so here's what i tried for my first go ...

1) Apple Cider Vinegar bath for 18hrs
2) Baking soda water bath and agitation for an hour
3) Rinse with warm soapy water
4) Baked @ 450 on a cookie sheet for 45min
5) Quenched in Vegetable Oil
6) Rinse with warm soapy water
7) Patted dry with dishtowel
Back in warm oven to dry out (warmed them up and slowly cooled off w/ oven)

The finish came out looking pretty good. Dark but not black. It has a brown tinge. I'll edit and post a pic as soon as I can.

I just need to do a few little tests to see if they scratch and see how they oxidize. Who cares if they look good now but rust up fast...

it's important that you apply some kind of rust preventative after you apply any kind of oxidation. so light machine oil, or wax, or something.

when you get most black oxided steel parts, the main rust prevention is the oil, even if it doesn't appear oily, the microscopic roughness holds the oil particles.

brownells sells a cold bluing solution that will likely give the best consistent results. also look up parkerizing methods.

lmw94002 wrote: The finish came out looking pretty good. Dark but not black. It has a brown tinge. I'll edit and post a pic as soon as I can.

As long as your coating prevents oxygen from contact with the metal you should be good.

Here's the image... not as good looking when up close... Probably could have done better cleaning/polishing before trying this. But this was just me tinkering around.