aluminum to steel

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can it be welded, haha, jk....i owuld like to be able to build flotation pods for my small aluminum boat, the problem is, is i can't weld aluminum, only steel.  i ran across these sorta plans and really liked these bolt-on styles:http://www.jphilarnold.com/pods/i know these things are really helpful but not worth $200, i could easily build someout of steel, but is there a ferosity problem or anything with bolting steel to aluminum?  btw, i dont even know what ferosity is i just thought it sounded right....lolif there is a problem with it could i put something like plywood or some sort of spacer in between them so the metals don't touch?thanks, fishon
Reply:The process I believe you are referring to is Galvanic corrosion, or some times refereed to as dissimilar metals corrosion. Alum/ steel will corrode to a limited degree due to the fact that metals are dissimilar.If the question is how to "weld" steel and alum together, they will braze with some alloys like silver solder or there is always epoxy resins and glue the 2 together. The epoxy will help to reduce or eliminate the galvanic corrosion, as the epoxy will insulate the two metals from each other..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:actually i  was joking about welding them,  i was wanting to bolt them together so icould take them off when i sell the boat.  could i coat both the pod and the area of the boat where the pod attaches with resin to reduce the corrosion then bolt the pod to the boat?  that sounds good thanks
Reply:You don't have to coat both, just coating one will help to limit the corrosion.Also sacrificial anodes are frequently used with salt water boats. Usually made of zinc, the idea is that these items "collect" or "attract" the corrosive energy and corrode rather than the other parts, The zinc's are easily replaceable.brass/steel in saltwater is an excellent example of Galvanic corrosion. I have seen brass fittings that look almost like new after years of submersion in saltwater, but the steel they were attached to is completely gone..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:it is possible to weld alum to steel, the process is called "cold welding" and is used in the automotive industry from what ive heard.