Best welding rod for aluminum to be anodized

[kjoiner]

Hello,

We have 2 extrusions that must be welded together and then anodized. Eventually this will be tooled as one extrusion but we are doing some field testing. I searched for the best welding rod to use so that no smut will form on the weld during anodzing but I have seen two opposite answers.

I have seen 5356 rod and 4043 rod mentioned. The two previous places I looked had opposite opinions about which one to use and which on to avoid. Which rod should be used?

Also, there will be a tab that ties the two parts together. How critical is the alloy for the connector tab? We typically use 3003 or 5052 for sheet metal parts but if that is a problem, I can spec 6061 for the tab as well.

The extrusions are made from 6063-T5 and will be clear anodized after welding.

Kyle

 

[TVP]

5356 will anodize better than 4043. The high silicon content in alloys like 4043 and casting grades 380, 390, etc. make for poor anodizing.