Will Brouwers Posted February 15, 2022 Share Posted February 15, 2022 Hello all, I have done some reading on zinc poisoning and decided to get your opinion. I received an old boat motor from a friend of mine for scrap. While tearing it down to separate aluminum from steel, I came across these two shafts. I thought they would be perfect for some struck tooling, but wasn’t sure about them because of how shiny they are. Should I just scrap them? Should I try to let them rust? I read about the pinholes that iron can bloom through and make it look like the material is all rusted up when it isn’t. Thanks for the advice guys! Quote Link to comment Share on other sites More sharing options...
George N. M. Posted February 15, 2022 Share Posted February 15, 2022 I would doubt that they would be plated with anything in that application. Shafts are a high friction part and any plating would quickly wear off in use. If there was any doubt in my mind I would put a bit of something acidic on it, leave it overnight, and see if there was any oxidation the next morning. Also, you could hit it with a file and see if there is any color difference between the surface and the metal a bit deeper. Or, if the cut oxidizes differently than the surface. "By hammer and hand all arts do stand." Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted February 15, 2022 Share Posted February 15, 2022 Most of the shafts I have encountered were 630 stainless steel. Quote Link to comment Share on other sites More sharing options...
Daswulf Posted February 15, 2022 Share Posted February 15, 2022 Oily internal engine/transmission parts can look shiny and resist immediate rusting due to the oils/fluids on them. Degrease them to see if they rust. Georges suggestion of removing some to look for differences is good. Stainless is a possibility but "probably" not typical in internal engine parts unless maybe an outboard motor? Also spark test may tell a little of what they are in terms of carbon. Stainless wouldnt rust even in the spot ground down while plated would rust in the ground down spot. A mix of vinegar, salt and hydrogen peroxide spray will show fairly quickly on degreased steel if it will rust or not. Quote Link to comment Share on other sites More sharing options...
Will Brouwers Posted February 15, 2022 Author Share Posted February 15, 2022 Thanks for the quick replies! I just tested it with a magnet, and it stuck like regular steel. I think that eliminates stainless. I will definitely try cutting it and filing it to see if it rusts! BTW, these are from an old outboard boat motor. Quote Link to comment Share on other sites More sharing options...
Scott NC Posted February 15, 2022 Share Posted February 15, 2022 Just for future reference, I copied and pasted this from the internet: "Stainless steels are iron-based alloys primarily known for their generally excellent corrosion resistance, which is largely due to the steel's chromium concentration. ... Due to this difference, ferritic stainless steels are generally magnetic while austenitic stainless steels usually are not." Quote Link to comment Share on other sites More sharing options...
JHCC Posted February 15, 2022 Share Posted February 15, 2022 10 hours ago, George N. M. said: I would put a bit of something acidic on it, leave it overnight, and see if there was any oxidation the next morning. Or leave it outside for a year or two. Slower, but just as effective. Quote Link to comment Share on other sites More sharing options...
Will Brouwers Posted February 15, 2022 Author Share Posted February 15, 2022 Thank you for that post Nodebt. I think I found a thread about forging stainless that I will read when I find the chance. Quote Link to comment Share on other sites More sharing options...
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