Sorry, but the following is completely wrong. The explosively jointed
bimetallic strips have a long and successful history. The aluminum is
welded to the aluminum side and the steel to the steel side. The
strips simply seem to have become hard to locate, at least via the
web.

Regular steel and stainless steel are often joined. Problems can
occur, especially if submerged in salt water but you'll see mild steel
/ stainless joints on fishing vessels that have been going for years
and years.

True, you can't weld aluminum directly to either.

How do I know about aluminum superstructure on a steel hull?

I did it on this boat:

http://www.bbsr.edu/About_BBSR/Facil...herbird_ii.htm

--

Roger Long



wrote in message
...
I have just double check with my friend who worked as a welder for 35
years in a shipyard that build commercial, coast guard vessels,
battleships and drilling platforms.
If you have an aluminums structure welding steel plates on or doing
the reverse was not in practice. Aluminums and mild steel or cold
rolled steel are not compatible. The same thing applies to welding
stainless steel. What takes place is a white inter granular
corrosion that is hardly visible to the naked eyes. Given time the
white corrosion will cause a structural failure. Not to mention the
saline atmosphere at sea that will accelerate the process.

"André Langevin" wrote in message
...
Hi to all,

I am a newcomer on this newsgroup and you'll see me around as i'm
starting the construction of a new boat. I currently have a 34
feet powerboat in aluminum and my nest boat will be a 44 or 45
steel sailboat. I'm looking at building a Bruce Roberts design and
i would like the deck superstructure to be in aluminum. I've seen
many commercial boat done this way and even old Coast Guard patrol
boat of 30+ years old without any corrosion problem so it is
something i'd like to do. But i can't find any industry that
carries the special strip that isolate both metals but still permit
to weld them both.

Does someone ever see this ?

André