So, after what I felt was an appreciable amount of research I made myself an anvil. I had about 3.5' of railroad rail, so I cut off some (12" or so) of the rail side webbing, milled a smooth face on it, and welded it stoutly to the end of the remaining rail. This gave me a narrow work face, but still a nice flat surface with a lot of mass right under the face. The heel and horn sides of the face piece (I flame cut, then ground a horn on one end) extended past the center of mass, so I added some gussets. Add a 1" hardie hole, and that's what I've been using for the past year or two. The problem at this point is that the gusseted ends are not providing enough stability to forge on.
Now, the point:
I have a piece of 1.25" steel that I would like to attach to the existing face of my current anvil. If I put a good bevel on the narrower current face, preheat both pieces, and weld the heck out of the entire perimeter, will the resulting void ruin my homemade anvil?