I have used quite a bit of the stoodite 12 and stellite 12, which are pretty much the same thing. You don't use any flux with them. These bare rods don't flow freely, and as a result, the beads can be stacked very nicely when building up worn edges. I found that TIG welding offers a lot more control than oxyacetylene. Preheating and slow cooling are important to minimize stress cracking. You can stick weld as well if you want a thinner overlay, but you don't obtain the same degree of hardness with the first pass, and the coated rods are also more expensive. I have used the bare rods as large as 1/4", and with practice, you can apply it very evenly, especially when using TIG.