For example would a piece of aluminum plate be able to be welded onto the end of whats basically a cast aluminum boxand be strong enough to withstand around 80-90psi of pressure(intake air). I assume anything possible if done well enough and i plan on the welds being proffessionally done, but i know cast iron is a pain for strong welds, does this hold true for cast aluminum as well?
I guess it would be worth a shot at least, but i'd like some type of answer before i put much more work into it.

 

you can weld cast aluminium fine, it is nice to know what grade of alu. it is.
i welded my intercooler back togeather and it holds 40 psi at least

 

they actualy make a special tig rod for cast aluminum i forget the alloy

I weld cast aluminum lower units on outboards all the time and they do just fine

 

We do a lot of heavy cast aluminum welding here. Mostly 319 and 356. Depending on the specific application, we would be using 2319, 4043 and 4643 filler metals. No Tig for this stuff - Mig only. We would only ever Tig much smaller parts. We almost always weld castings to extrusions - mostly 6061 and 6063. No problems at all (other than heat treating issues - not related to weldability, though)....it is nothing like cast iron!

Some heavily alloyed cast aluminum is not weldable so beware....but if you have a weldable alloy, what you described is perfectly feasible.

 

sounds good thanks for the info guys, ive never messed around with aluminum, want to mess with it but not on this...I have an aquaintence thats a welds for a proffession so I'll have him look at it to see what he thinks he could do with it. I just wanted to know it could be done before i got too crazy about the idea and tracked him down. I'll throw up some pictures once it comes together a bit.

 

Hey Kenny D
what do you use to weld the outboards with?
Heliarc?

 

Right rod, right flux, right machine, right guy......you can weld just about anything.