Aluminum Repairs

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I am about to break down the windshield frame on my boat to replace all of the rivets and scews and such as well as polish it up real nice like.  The windshield frame has survived 38 years of indecisive owners who drill holes for accessories and then decide that isn't where they want it.  They also put steel rivits in it and the electrolysis left giant pits around the steel rivits.  I am unsure of the material, therefore, am unsure of the feasability of welding it.  Also, I do not own an arc welder and will be using an OFW setup.  Because of these conditions, I would prefer to solder the aluminum.  The question is, will the solder hold up in a corrosive salt water environment and will it be able to be polished to match the aluminum?  I bought some AL-3 aluminum soldering rod from Bernzomatic at my local hardware store and thought I would play around with it on some scrap first, but I wont know about it's longterm characteristics.  Also, since it's a solder, will I be able to grind it out and weld it if I change my mind?  I know most brazes alter the structure of the metal so it can no longer be welded.
Reply:well i've never even come close to even trying to do what your trying to acomplish..but i'd say your wasting your time because the base metal is so corroded and deterioated..the contamination will be too much to overcome..unless you get to "virgin" casting i'd fugettabuotitand look for a replacement part..in the long run it would be much easierjust my 2 cents worth...zap!
Reply:It's not that badly corroded or anything, just the typical white spots.  I wanted to plug up some of the holes people have drilled over the years.  It's not really possible to get a new windshield frame for a 1968 boat who's manufacturer, SeaBird, went out of business some time in the 70's.  Oh yeah, and if I want to get the thing anodized, how would the solder take to that?
Reply:The proper way is to TIG weld the locations.  The choice of alloy to use is very important if it is going to be anodized.  Some weld alloys do not anodize well.  In the case of your torch brazing I suspect that your filler will be some sort of zinc alloy and the colour match will be poor.  If you are going to do this polish it afterward then clear coat the thing.  An automotive clearcoat should stand up to the sunlight.