#11
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Quote:
316 will push around for a while with a hammer but it work hardens very quickly. If you can get it a dull red with heat it is like putty and works really easily. You can pickle the welds with hydrofluoric acid afterwards but it's a nasty chemical and they shine up equally well with Scotchbrite and isopropanol alcohol. Living by the coast with lots of yacht types and fishermen I've had more than my share of stainless work that then went off to earn its keep amongst rolling seas and saltwater. I hate the stuff but people have paid me enough over the years to learn how to make it behave and the only big no-no with anything you build from 316, (or 304), is to mount it in such a way that it won't flex and twist with the natural movement of the boat / car / aircraft or whatever it's attached to, 316 will crack for fun. Mash it into shape, weld it up then don't stress it and it will outlive us all. Will
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Here to learn. William Pointer |
#12
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Hi Will,
excellent post ! This comes at the right time, as I have the metal priced and was planning to get it tomorrow after work, so thanks, perfect timing. TX Mr fixit Chris |
#13
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I'm familiar with alloy 316 for aviation....
"Heat and beat" are the bywords we use in the USA .... for working stainless to appreciable degrees ... Be careful on your input heat - no orange. Red, dull red, is best. When metal becomes resistant... heat glow subsides ... DO NOT hit harder. Simply add more heat, get back up to working temp ... dull red ... lights NOT bright ... Blacksmith environment ... dirt floor, dark wood walls, kerosene lamp ..... Do not quench with water, oil, or air. Just let it cool, all by itself. And when all done fitting and welding .... neutralize the oxidation potential ... neutralize the tendency to rust .... inside, out of view ... along the seams ....
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#14
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WOW, is all I can say! You guys come through every time I post my crazy questions with such great help.
Again all I can say it Thanks. TX Mr fixit Chris |
#15
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Can anyone outline a reliable low tech methodology that they've used to successfully passivate? Some reading I've done suggests that when improperly attempted, it can lead to worse corrosion potential down the line. I'm just beginning to learn a little about the subject. Thanks.
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#16
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Quick web search
Passivation is the process of treating or coating a metal in order to reduce the chemical reactivity of its surface. In stainless steel, passivation means removing the free iron from the surface of the metal using an acid solution to prevent rust. I was advised to use Nitric Acid, but other references advise milder treatments such as Citric Acid. Personal "due diligence" brought to the highest level by Kent White, supports each of us should consider several sources. FWIW
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Marc |
#17
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Passivation method, from my "Welding Stainless" booklet
Quote:
Hi Mark, In the little booklet I wrote on "Welding Stainless" I mention 1) pickling stainless 2) bright dip for stainless and 3) passivation. Quoting from my booklet: ..... "In any case, passivation is the very last step in the welding process of any new or repaired parts, and is performed to restore the lost corrosion resistance by dissolving any embedded particles. The material is simply immersed for 20 minutes in a 15-20% nitric acid solution at temperatures between 120-150°F. This in no way affects the surface finish, so even those parts which have received a high polish earlier need nothing after this process." .... https://www.tinmantech.com/products/...-stainless.php
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#18
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Thanks Marc and Kent for the feedback. I'll order a copy of the suggested booklet. Much appreciated!
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#19
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Yes, Marc and Kent, thanks for the detailed information. Kent I too will order a copy of the suggested booklet. Much appreciated!
TX Mr fixit Chris |
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