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  #11  
Old 01-31-2019, 07:47 PM
AllyBill AllyBill is offline
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Originally Posted by Mr fixit View Post
OK Kent,

Home work it is!! I learn something new every time I log in to this site, which is often and so awesome
Other question, can SS 316 be hammer formed?

TX
Mr fixit
Chris
Hi Chris,

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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  #12  
Old 01-31-2019, 08:48 PM
Mr fixit Mr fixit is offline
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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
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Chris
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  #13  
Old 02-01-2019, 09:00 PM
crystallographic crystallographic is offline
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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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  #14  
Old 02-03-2019, 12:13 AM
Mr fixit Mr fixit is offline
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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
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Chris
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  #15  
Old 02-03-2019, 11:11 AM
mark g mark g is offline
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And when all done fitting and welding .... neutralize the oxidation potential ...
neutralize the tendency to rust .... inside, out of view ... along the seams ....
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  
Old 02-03-2019, 12:59 PM
Marc Bourget Marc Bourget is offline
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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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  #17  
Old 02-03-2019, 06:48 PM
crystallographic crystallographic is offline
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Default Passivation method, from my "Welding Stainless" booklet

Quote:
Originally Posted by mark g View Post
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.

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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  #18  
Old 02-03-2019, 10:31 PM
mark g mark g is offline
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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  
Old 02-03-2019, 11:33 PM
Mr fixit Mr fixit is offline
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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
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