Yes you can, but I have never heard of it being recommended. Aluminum arc welding rods can be bought, but are only meant for a welder that has a direct current output or has direct current capability. It is easy to know if your welder is the right one because it will be labeled so. As for buying rods, you can buy them from welding supply stores, but the easiest is to buy it from McMaster-Carr. Their website is here:
http://www.mcmaster.com/
Search their site looking for arc welding electrodes. The specific electrode you are looking for is specialty electrode E4043. The E means it is a electrode and the 4043 is the number for that specific aluminum alloy. It will be $15 for a half pound of welding rods, and there are 35 to 50 rods per pound.
However, I must add that since you have never used an arc welder before, learning to weld using aluminum rods might end up being very discouraging. Practice with steel first and steel welding rods to get the feel of it, then try aluminum. And always, tell us how it goes!
