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Old 01-28-2019, 09:25 PM
Mr fixit Mr fixit is offline
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Default Type of Stainless Steel to hammer shape

Hi Group,

I have a friend that has a early Buick 1920's that he got as a unfinished project that the previous owner had a SS gas tank made, not factory.
I have a car project that making a SS gas tank would be a real great idea and last for ever.
The question is what type of SS to use since mine has rounded 90* corners that will need to be hammer shaped.

Any and all comments welcome.

TX
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  #2  
Old 01-30-2019, 12:28 PM
crystallographic crystallographic is offline
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Quote:
Originally Posted by Mr fixit View Post
Hi Group,

I have a friend that has a early Buick 1920's that he got as a unfinished project that the previous owner had a SS gas tank made, not factory.
I have a car project that making a SS gas tank would be a real great idea and last for ever.
The question is what type of SS to use since mine has rounded 90* corners that will need to be hammer shaped.

Any and all comments welcome.

TX

I'm no expert on tank construction, although I have made a few using different metals.
Sunbeam 1926.jpg
1926 Sunbeam tank, soldered 304 stainless, exact as original.
1914 Packard tank, Browning.jpg
1914 Packard Roadster, 304 soldered stainless, exact as original, tank sits behind driver, exposed to full view, passed Pebble Beach judging, car got high marks.
1934 Packard tank.jpg
1934 Packard tank, 304 soldered stlss, with internal electric pump, serviced through access plate (shown).
304 full soft is good. or 1/4 hard.

I use equal thickness to original terne tanks.
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Old 01-30-2019, 07:04 PM
Mr fixit Mr fixit is offline
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Hi Kent,

I appreciate your responding. It looks like if I do this SS 304 soft is the metal to use. I hope to make it in multiple pieces and TIG it together for a rust resistant tank.
I have an old one that has holes in the bottom that i plan on cutting apart to see what the baffles look like and then get a steel filler neck that fits in the body with a section of hose to connect the 2 together.
Is there a difference between soft and 1/4 hard SS 304 in terms of ordering it, or is this a annealing treatment that is done like with some regular aluminum sheet metal.

Again,

TX
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Old 01-30-2019, 07:40 PM
AllyBill AllyBill is offline
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Hi Chris,

If you really don't want it to rust, ever, do it in 316 and TIG it together. Just be sure with 316 to do everything slowly, drilling, cutting, pushing it around, because it work-hardens if you give it a hard stare.

Will
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Old 01-30-2019, 07:49 PM
crystallographic crystallographic is offline
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Default passivate stainless welds

Quote:
Originally Posted by AllyBill View Post
Hi Chris,

If you really don't want it to rust, ever, do it in 316 and TIG it together. Just be sure with 316 to do everything slowly, drilling, cutting, pushing it around, because it work-hardens if you give it a hard stare.

Will

Yeah, and be sure to passivate the whole welded tank too, or the welds will rust.
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Old 01-30-2019, 07:57 PM
crystallographic crystallographic is offline
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Quote:
Originally Posted by Mr fixit View Post
Hi Kent,

I appreciate your responding. It looks like if I do this SS 304 soft is the metal to use. I hope to make it in multiple pieces and TIG it together for a rust resistant tank.
I have an old one that has holes in the bottom that i plan on cutting apart to see what the baffles look like and then get a steel filler neck that fits in the body with a section of hose to connect the 2 together.
Is there a difference between soft and 1/4 hard SS 304 in terms of ordering it, or is this a annealing treatment that is done like with some regular aluminum sheet metal.

Again,

TX

Hi TX,
Welding stainless always needs to have passivation done or the welds rust.
You order the stainless in the hardness you need - full soft or 1/4 hard. You really don't want to have to anneal any more than an edge that needs flanging around a radius- and those are best done hot. (I showed this on DVD, "Shrinking Magic.")
"Regular aluminum" must be soda cans?
I just finished some panel fab/shaping for a Sikorsky, and that was far from "regular" aluminum.
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  #7  
Old 01-31-2019, 01:16 AM
Mr fixit Mr fixit is offline
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Hi Fellas,

So SS-304 can rust? Can 316 be hammer shaped on the stump or bag? I need to make some round corners kind of like a loaf of bread.
Is a Nitrogen purge the same thing for passivation? If it is a coating will weldable primer do the job or is there a special product to be used?

I appreciate the help and comments.

TX
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  #8  
Old 01-31-2019, 12:33 PM
crystallographic crystallographic is offline
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Default

Quote:
Originally Posted by Mr fixit View Post
Hi Fellas,

So SS-304 can rust? Can 316 be hammer shaped on the stump or bag? I need to make some round corners kind of like a loaf of bread.
Is a Nitrogen purge the same thing for passivation? If it is a coating will weldable primer do the job or is there a special product to be used?

I appreciate the help and comments.

TX

All 300 series stainless needs passivation after welding.
ALL.
Here is your homework assignment: do an internet search on "passivation of welded stainless steel."
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"All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919.
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  #9  
Old 01-31-2019, 03:44 PM
eaglefordracer eaglefordracer is offline
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Default What makes stainless stainless?

It takes 12% chromium to be considered a stainless steel. The 304 and 316 are both referred to as austenitic stainless steel because they are single phase, and not heat treatable.


What keeps it from rusting is the layer (clear) of chromium oxide that forms in ambient air over time. When you machine, weld, abrade the layer, it takes some time for the oxide to re-form. How fast is dependant upon type of air, moisture, and temperature.


For fabricated parts, to ensure that no steel is embedded into the stainless a passivation process is employed. Essentially it's an acid that attacks carbon steel, and promotes the formation of the oxide layer. Passivating something means you are making it less reactive, ie. won't rust.


And yes, stainless steel will rust...all you have to do is subject it to the proper conditions...only instead of getting orange red and black like carbon steel, you'll get lots of pits.
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  #10  
Old 01-31-2019, 06:13 PM
Mr fixit Mr fixit is offline
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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

Last edited by Mr fixit; 01-31-2019 at 06:15 PM. Reason: 2nd question
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