plating, anodizing, & finishing Q&As since 1989
Anodizing after welding process
We use aluminum alloy 6063 for our furniture. For some parts we need to weld it before anodizing (black). But even after polishing we still see that the color at the welding seam is different than the rest (bulk material). I think may be during the welding process the chemical/structure of the material at the welding seam is changed. Can anybody tell me how to achieve that.
Alternatively, can we glue it after anodizing? if possible then what kind of glue can we use?
For a good color match after anodizing welded Al-6063, use filler alloy Al-5183, 5356 or 5556.Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
The welding rod is a different alloy from 6063. The weld is a different alloy from the rod and 6063. The area around the weld is now a different alloy from the rod, 6063, and the weld itself. Every alloy will anodize a different color as a function of the non-aluminum ingredients . There is nothing you can do.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
Ken is spot on.
In fact I go even further and only recommend the 5356 alloy for welding aluminium that is to be anodised.
I recommend this to all our anodising clients that have experienced a colour difference.
5356 is a very good colour match when anodised with 6063 in a matt natural finish - it is therefore a good choice for bronze through to black anodised (Type II sulphuric process).
I believe that it is also an excellent choice for the general welding of 6063 - whether it is to be anodised or not.
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