As joining aluminum goes, (GTAW), 6061 is as friendly as it gets.

Here is a link with a ton of data, the question and answer portion is especially thoughtful.

http://www.alcotec.com/techpage.htm

Other good articles on welding aluminum can be found on www.millerwelds.com just type "GTAW Aluminum" into the site search engine and you will find a wealth of information.

As you proceed your questions will become more and more specific, those are the best kind.