Alloy 4043 is one of the oldest and most widely used welding and brazing alloys. Almigweld and altigweld 4043 can be classified as a general purpose type filler alloy. The silicon additions result in improved fluidity (wetting action) to make the alloy a preferred choice by welders. The alloy is less sensitive to weld cracking and produces brighter, almost smut free welds. New Old Stock