I am welding up bases for sculptures which need to look perfect.
The bases are trunkated pyramids which I assemble from 1/8" steel and weld using my mig welder. Then I grind the weld down to a nice radius, sand the whole thing to a satin finish and off it goes to a museum or such place.
The problem I am experiencing is that after I mig weld the joint and grind the weld down sometimes I find low spots or inclusions, nothing major usually, most flaws of this nature are like pinheads, maybe bigger sometimes.
I have had no luck trying to fill these small imperfections by another pass with the mig gun, usually I make things worse when I try this.
So I fired up the TIG welder but even that is no easy fix. I am not so experienced with this machine (a brand new Lincoln Precision TIG 185) and I wonder if someone here can give me a few hints to avoid inclusions, a certain brittleness of the deposit and quite often a craterlike depression when the weld cools.
I am using 3/32" red marked sharpened tungsten rods, DC- mode with up to 120 amps and an Argon flow of up to 20 cf/h (I increased it a bit after I found a dark smoke deposit on parts of the weld but a slightly higher flow rate did not change that). When I try to fill these depressions or holes I try to use very little pedal.
Thanks in advance for any advice
Uwe