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Old 26 September 2004, 20:21   #1
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Stainless steel grades

Hi all,
Would appreciate some advice re. use of stainless steel fasteners! I know that 316 is commonly used as a marine grade stainless steel, but what fasteners are best? A2 / A4 commonly available, which is better or should I look for something else?

Thanks!
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Old 26 September 2004, 21:13   #2
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a4 unless sombody with a name beginning with J says different
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Old 27 September 2004, 03:09   #3
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...you know, what you really need to use is...
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Old 27 September 2004, 03:23   #4
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As I understand it, A2 fasteners are manufactured using 304 grade SS, and A4 with 316 grade (the better marine/medical/food grade)

A2 tends to leave dark streaks down ya shiney bits when exposed to the elements, unless it's highly polished, which seems to stop that happening.

Hope this helps.
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Old 27 September 2004, 03:31   #5
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well done mr smart pants

when I said somebody with a name begining with J i meant Johan from the Falcon factory
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Old 27 September 2004, 03:44   #6
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As far as I am aware, JF is right ...... Dont use anything less than 316 on you boat , in salt water...... I will break your heart
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Old 27 September 2004, 03:51   #7
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I hate to contradict FGT........ so I won't...

...'course if you seriously want to acheive better pitting resistance in sea water try getting ASTM spec bolts (American spec.) B8MLCuN or UNS32154's as the increase in Molybdenum to 6% gives much higher resistance than 316/A4's 2-3%....Now THAT'S what I call anorak knowledge..
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Old 27 September 2004, 03:54   #8
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Jono, we need your knowledge (you Nobba) pray tel!
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Old 27 September 2004, 03:56   #9
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So 304 is A2, and 316 is A4?
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Old 27 September 2004, 04:17   #10
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Quote:
Originally Posted by Jono
I hate to contradict FGT........ so I won't...

...'course if you seriously want to acheive better pitting resistance in sea water try getting ASTM spec bolts (American spec.) B8MLCuN or UNS32154's as the increase in Molybdenum to 6% gives much higher resistance than 316/A4's 2-3%....Now THAT'S what I call anorak knowledge..
Sounds great Jono - if you can tell me where to buy all this specialised stuff I would love to know - currently looking for some 1/2" UNF bolts for mounting engines in the strongest stainless stuff known to man!

Thanks -
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