ER4043 vs ER5356 when to use?

4043 is a general use aluminum filler for use on all weldable alloys. It is fairly soft, and shock resistant. It gives a good color match on 6061 if polishing or anodizing. 5356 is also a general use aluminum filler for use on all weldable alloys, but is stronger, harder and much more corrosion resistant. 5556 is a stronger version of 5356. The 5000 series alloys have the highest corrosion resistance. Marine aluminum is 5052 or 5086 plate welded with 5356 or 5556 filler.

The best filler for most castings is 4047. It has twice the silicon of 4043 so it has a lower melting temp, less shrinkage and better wetting.

4047 is fairly hard to find, but most large suppliers have at least one box sitting around.

The best article on aluminum welding I have found is in here.

Dang Ernie. Every time I read one of your posts I learn something useful. Maybe SEJW needs a sister FAQ site that is just filled with all your posts. Love that pamphlet you linked to as well. I skimmed it on-line, and just printed a copy to go on my "library" reading pile.

Bob La Londe

You can check their other back issues on the site, but that mag is very engineer oriented. The aluminum article was written in plain english, which is kind of rare for them. Still lots of interesting info for free.