4043 Aluminum Welding Alloy

Diameters / Packaging

1 lb. spool
4 lb Box
4 lb. box
5 lb. box
10 lb Box
10 lb. box
16 lb. spool
20 lb. spool
50 lb. box
.030 in. 04043E1
.035 in. 04043F1 04043F6
1/8 in. 40436011POP 04043605 0404360 A404360
1/16 in. 04043305 0404330 0404337
1/16" 40433011POP
3/16" 0404380
3/32 in. 40435011POP 04043505 0404350 0404357 A404350
3/64 in. 0404321 0404327 0404329
5/32 in. 0404370



Aluminum-silicon filler metal for welding heat treatable base metals and repairing cast alloys is less crack sensitive than 5356.


4043 is an all-position 5% silicon alloy used to weld heat treatable base alloys. It is most often used to weld the 6XXX series of alloys. The silicon addition improves puddle fluidity, producing an appealing bead profile. It is less crack sensitive on the 6XXX series than other welding alloys. 4043 is available for both GMAW (MIG) and GTAW (TIG) welding processes.


  • Designed for welding heat treatable base alloys, specifically 6XXX series alloys
  • Lower melting point and more fluidity than the 5XXX series filler alloys
  • Low sensitivity to weld cracking with the 6XXX series base alloys
  • All position welding rod
  • Often used to for repair welding aluminum/silicon cast alloys such as grades 353/A356
  • Common choice for welding 6061
  • Gray (post anodized) color
  • All position welding
  • Embossed with model number on each end for easy identification after use

Typical Applications

  • Repair welding aluminum/silicon cast alloys
  • Welding automotive parts, truck trailers and bicycles


Warning -

Cancer and Reproductive Harm -