Will Brouwers Posted June 11, 2022 Share Posted June 11, 2022 I think this is the right place to put this, although it is more a celebration of new possibilities than anything. One of my neighbors gave me 4 quarts of new 0w-40 motor oil and I spent the last hour testing out pieces of scrap that I had that I thought might be high carbon. With this oil and the capabilities it gave me, I finished making my first tool, a hot cut chisel!! I’m pretty excited, because now I feel like a “real” blacksmith! I should also add that I have actual quench oil on my list of things to buy, this motor oil just came to me and I decided to see what I could do with it! Quote Link to comment Share on other sites More sharing options...
George N. M. Posted June 11, 2022 Share Posted June 11, 2022 Will, it looks like you forge and quench outside which is good because the smoke and fumes from quenching in motor oil, new or used, can be toxic due to the various additives. Not drop you in your tracks toxic but not good stuff to be breathing. That said, I used motor oil as a quenchant for years before I came to the light and bought a couple gallons of generic Wally World cooking oil. I don't do a lot of quenching of high carbon steel and quenchants don't see a lot of use in my shop. "By hammer and hand all arts do stand." Quote Link to comment Share on other sites More sharing options...
JHCC Posted June 11, 2022 Share Posted June 11, 2022 Even new motor oil is not a good quenchant. According to British metallurgist Graham Clarke, the additives that go into engine oil (detergents and the like) lower the boiling point of the oil, which increases the problems you run into with vapor jacket formation. This results in a slower, uneven quench. Proper quench oils have very few additives, so the boiling point remains high. Mr. Clarke’s discussion of quenchants starts at the 4:47 mark in this video: https://youtube.com/watch?v=Yv5Xz8rI6Fs Quote Link to comment Share on other sites More sharing options...
Will Brouwers Posted June 11, 2022 Author Share Posted June 11, 2022 I really appreciate the concern, both for my health and for the consistency of my forging. Before this, all I had was water, partly because if I was going to spend money on quench, it was going to be the good stuff. I am aware of how bad motor oil is to use, but for the price and the ability to practice, it worked just fine! Quote Link to comment Share on other sites More sharing options...
Randy Griffin Posted June 11, 2022 Share Posted June 11, 2022 Regular old canola oil is the good stuff. Unless you use some of the more exotic steels all you need is canola oil and water. Quote Link to comment Share on other sites More sharing options...
JHCC Posted June 11, 2022 Share Posted June 11, 2022 Dr. Larren Thomas has a good overview of quenching oils here: https://youtu.be/Vdy0nvVEtJY Quote Link to comment Share on other sites More sharing options...
Paul_Lake_Echo Posted July 13 Share Posted July 13 I hope this is an OK place to post this. I'm trying to make a few chisels from an old truck coil spring. I annealed sections, and they softened up nicely. They were easy to work on, and I got the shapes I wanted (curved, a couple of eye punches, and a butcher hand punch). I quenched them in old transmission fluid and then tempered them at 450 F for a couple of hours in a toaster oven. The problem is they are too soft. My guess is because I only had a small amount of transmission fluid, probably 2/3rds or a quart, it was too hot for the quench. It flashed a lot of flames on the surface, especially with the 2nd, 3rd and 4th quench. I can't easily get a few buckets full or more. The question is, will they be as brittle as glass if I redo them and quench them in water? If so, will tempering them at 450 F for a couple of hours and then letting them air-cool work? I don't know what kind of steel they are other than the springs spark nicely with a grinder. I suspect they are fairly high-carbon steel, and I hope they will work. Do you guys have any suggestions? - Paul Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted July 13 Share Posted July 13 try a plain section of the coil spring and see before you risk killing your chisels Quote Link to comment Share on other sites More sharing options...
Florida Man Metals Posted July 13 Share Posted July 13 I once read an article in some handgun magazine years ago about a guy that made custom high end 1911s. The article was something about golden guns. I believe the guy was quenching every part in new motor oil. It had a beautiful golden finished when done. It wasn't gold plated or anything like that. Quote Link to comment Share on other sites More sharing options...
George N. M. Posted July 13 Share Posted July 13 The problem with quenching in motor oil is the additives that come off in the smoke of the quench which are not good to breath. It is worse for used motor oil because of the additional gruk from the wear of metal in the engine and the heat degredation of the oil. If you did it outside in a breeze the damage could be minimized by the smoke blowing away from you. Other than that oil as a quenchant is no better or worse than other oils ( anything from commercial quenching oils to crude oil to various exotic plant oils) and largely depend on the boiling point of the particular oil and how it forms bubbles at the surface of the metal. And, of course, the other variable is going to be the characteristics of the steel. No quanchant is going to be optimum for every alloy of steel. Yes, I have quenched blades in used motor oil in the dim past successfully but like various other things I did in my younger years would I want to do it again. IIRC it left more of a black carbon build up on the blade that had to be ground or sanded off to get back to bare metal for tempering. "By hammer and hand all arts do stand." Quote Link to comment Share on other sites More sharing options...
Nobody Special Posted July 13 Share Posted July 13 The smell when you temper one in the oven after motor oil...blech. I'd try what Steve suggested - take a piece of the spring or forge it into a test coupon then try gradually increasingly aggressive quenches until you get that lovely glassy sound. Normalize it first, take it up to a little beyond non-magnetic, and quench in oil, then if that fails, repeat with water, then brine, then super-quench. Car oils make for lousy quenchants and are moderately toxic - go nuts and blow the seven bucks for a gallon of vegetable oil. The oil also will actually tend to work better if you pre-heat it a bit with a hot rod. And yes, it will flame. It's good to have something nearby to put on top of it to put the flames out and to smother the fire if you spill. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 13 Share Posted July 13 When quenching in oil submerge your blade or whatever completely in the oil. You'll know it's deep enough when the flames go out. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted July 13 Share Posted July 13 If you have a favorite cafe that the folks there know you, see if you could get a 5 gal bucket of their used fryer oil. They usually change their oil on a regular basis and mine was happy to save 5 gal. in a bucket with a lid I left them. The shop will smell like french fries when you quench something. I can't control the wind, all I can do is adjust my sail’s. Semper Paratus Quote Link to comment Share on other sites More sharing options...
Daswulf Posted July 13 Share Posted July 13 Free oil could be had easily after Thanksgiving. People use a lot of oil to fry turkeys then typically pitch it out. Put a wanted post on fb or craigslist or something and you'll probably get more offers than youd want to take. If you know someone that fries a Turkey just ask them. It is typically around 5gal. To fry and in a quench tank that would usually be more than enough. I use a larger ammo can so if need be I can close the lid. Also heat it up before quenching. I put a larger bar of steel in the forge and use it to heat the oil. I typically heat it to around 140°F Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 14 Share Posted July 14 Bakeries and delis shops go through a huge amount of peanut or canola oil. I asked at the local Safeway and provided a new/clean 5gal plastic jug. J.R. told me to hang on a minute and I had a full jug in less than 5 minutes. To keep your pastries from tasting like fish they change their oil every day. Oil from a bakery will make your shop smell better. Maybe in general. Early morning was the best time to hit Safeway, they fry pasteries at night and switch to breakfast burritos about 5am. It pays to be on good terms with the bakers, they'll use your jug and set it aside for you. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
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