Re: [PSUBS-MAILIST] stainless vs aluminum

[MerlinSub@t-online.de]

The main ballast tanks of Eurosub are made from aluminium. 
The main reason was the center of graphity of the boat in height direction.
For the reason that I also can not weld alumium we give the welding away to a yard.

In general I work better with stainless but be carefull - stainless in combination
with other metals like brass/bronze etc can give way very quick in saltwater. 
Stainless to weld is relative easy but weld schrinking and bending of the metall is an issue. 

vbr Carsten

<ShellyDalg@aol.com> schrieb:
> Hi Brian. Welding stainless is easier than aluminum and it's more corrosion 
>  resistant. A bit of paint on the aluminum will take care of that if you 
> keep an  eye on it and touch up the paint as needed.
> It's easier to cut and drill aluminum but I prefer stainless. It's not that 
>  tough to work with. I generally use a portable band saw to get the general 
> shape  or size needed, then a 4-1/2 inch grinder to finish it off. I also 
> use the  grinder and a 1/16 inch cut-off blade for cutting larger pieces of 
> sheet like  for my ballast tanks etc. 
> A lot depends on your source for material and which one is cheaper. For me, 
>  stainless is easier to work with because of it's weldability. It can be 
> bent  and/or folded where aluminum can't without cracking.
> If the stainless has been cut or welded and I think the corrosion  
> resistance has been lost I use a wire wheel and a sanding disk to polish it up a  
> bit. Sometimes a buffer wheel and polishing compound stick to get a good 
> shine.  It doesn't get rusty then unless I've gotten the piece really hot so that 
> the  chromium boils to the surface. In that case I sand away the surface 
> and lay a  little more stainless rod over it, sand to contour and it's good as 
> new. If the  part will be in contact with concrete then aluminum won't 
> work. The alkali in  the cement eats aluminum in short order. You could put a 
> separator like nylon or  something between them but why make it more 
> complicated.
> If you have the equipment to weld aluminum there are some places where it's 
>  good because of it's light weight but generally stainless will out last 
> aluminum  by 2 or 3 times it's life span. Look at sailboats and you'll see 
> very few  aluminum fittings there. Mostly stainless unless weight is an issue. 
> If aluminum  is used it's anodized and/or treated and requires more 
> maintenance.
> Frank D.
> 




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