Difference between RST and haponkestävä A4

[rod1e]

Hello, it's been many years since I've been here...

Can someone tell me the difference between RST fixings, screws and things. ... and ones that are marked haponkestävä A4?
I know that A2 class is registered as not suitable for seawater and A4 is OK. But what is RST?
Any help would be much appreciated.
Cheers
rod

[mtuitto]

RST is same that A2. RST is "ruostumatonteräs" in finnish.

[VilleS]

This might be usefull... You can find it all here .

http://en.m.wikipedia.org/wiki/SAE_steel_grades" onclick="window.open(this.href);return false;

[rod1e]

Thanks guys... that's helped me work things out...

So RST just means standard Rosteri: A2 or EN 304 or 18/8

and marine grade stainless is A4 or EN 316(L) or 18/10 (surgical steel?)

Was just looking at different screws... also very confusing...
Kestopuuruuvi, Terassiruuvi, Yleisruuvi, Levyruuvi, etc

Do you think the A2 grade is OK for planks in a boat or should I make sure everything is A4 grade?

Cheers
Rod

[Lampila]

I have been using A2 in some internal or interior parts of a boat but not in those parts of a hull that are contacted with the water all the time. Are you making a total new boat or repairing old one? If new one then i would say definitely A4.

[VilleS]

It might be reasonable to use grade A4 everywhere, but you should use only A4 grade below seawaterline and you can use A2 above. You can also use bronze wood screws, those you can use in anyplace (high seawater resistant) .

http://www.toplicht.de/en/shop/bootsbau ... e-senkkopf" onclick="window.open(this.href);return false;

[rod1e]

OK, thanks for the advice.
I'll use A4 throughout.
It's a new boat, small sailing dinghy...
Cheers
Rod