Any good machine shop should be able to weld aluminum.
I can't tell you how often I have cut layer upon layer of tape off spreader ends, turnbuckles and sometimes even just the wire. It's not a good idea. what's worse is when someone wraps a few yards of spinnaker cloth around the end of the spreader in an attempt to fabricate a boot of some sort (I guess). Usually when I remove that I just end up with a handful of white powder. (no jokes please)
Another thing while I'm on the subject, please, if you must use those silly little shroud covers. You know the ones I mean. They are made of white pvc and are slit so that you can slip them over the shrouds to ostensibly protect the jib sheets. Please use over-sized ones and lift them up and rinse and dry underneath them once in a while.
Better yet, toss them in the nearest dumpster and replace the sheets when they need it.
Let your metal breath. Let the moisture dry. Rinse the salt out. Don't do or buy crap just because most of the boats in the marina do.
But then again I love selling people new rigging. So what the hell am I saying. Use that tape and lots of it.