Aluminum Smooth 340 Maintenance And Repair Electrodes Feature A Precise Combination Of Core Wire And Coating, Providing High Speed Deposition Of Dense, Machinable Welds. It Is Recommended For Fabrication And Repair Of Cast And Wrought Aluminum. It Is Excellent For Foundry Defects, Machining Errors And All Types Of Salvage Work. Coated Stick For Fabrication, Maintenance Of Repairs Of Cast Or Wrought Aluminum Base Metals. It Is Widely Used On Sheets, Tubes And Extrusions In Thickness Of 1/8Or More. Smooth 340 Is Also Well-Suited To Torch Applications Such As Aluminum Motor Blocks And Cylinder Heads, Machine Bases And Supports, Housings And Mounts. Procedure: Use Dc Reverse Polarity. Weld Areas Should Be Clean And Heavier Sections Should Be Beveled. Best Results Will Be Obtained On Heavier Sections When Preheated To 500 Degrees Fahrenheit. The Electrode Should Be Held In A Vertical Postion. Slag Needs To Be Removed Before Multiple Passses. Clean With Hot Water; Add 10% Sulfuric Acid To Water If Additional Cleaning Is Required.