Over on the IForgeIron blacksmiths' board, someone asked if Thermite could be used to reweld on a broken anvil horn, or other similar uses.
That got me wondering if Thermite could be used to weld on a new faceplate to an anvil.
Many older anvils have had a great deal of use, and cracked, chipped or swaybacked faces, and many cheap import anvils are naught but cast iron, too soft and pretty much worthless as a usable anvil.
A faceplate is easy to fabricate (say, a plate of S7, milled in the annealed state) but very difficult to properly attach to the anvil body. The old way- turn of the century- was to forge weld them all together, but this takes a great deal of heat, time and skill.
Modern electrical welding is ill suited for a 2" or 3" deep weld, and is used mainly just for repair or refacing using hardfacing electrodes. Brazing has been suggested as possible- requiring less heat than forge welding- but likely to produce occlusions, and an overall-lower-quality join than a true weld.
But what about thermite? From what little I know about it- largely from YouTube videos - it seems it might be as simple as, say, making a fireclay/firebrick "dam" around the face of the anvil body, pouring on perhaps a quarter-inch of thermite, laying the milled tool steel faceplate on top, and lighting 'er off.
Depending on how it works and the materials involved, one might or might not quench (to get the faceplate hardened) but it seems to me the two parts would be pretty thoroughly welded.
I suppose it's something that would simply need some experimenting to see how it'd work, but I wonder if there'd be a risk of occlusions or voids... maybe lay the anvil on the side, let the weld burn vertically?
I may be interested in trying it- I have a century-old anvil I've been slowly repairing with hardfacing rods and other techniques (both MIG and TIG) but it's looking like the faceplate already had a great many small cracks before I ever started welding on it.
As bad as it is- and the labor it's taking to repair it with electrical welding- I'd love to be able to mill off some or all of the original face, and somehow apply a shiny new, flat and straight face, if it were, that is, as easy as a little fireclay, maybe some sand, and a few ounces of Thermite. (Where would one even buy it? I assume it'd be a closely-controlled substance...)
Any opinions or experiences? I know it's used to weld train tracks, and it's been used to weld large copper conductors, and the weld would be basically pure iron- though that's not a problem, my anvil body is pure wrought iron as it is. I don't see why it wouldn't work, but I can hardly afford to buy a bunch of plate tool steel, thermite, and chunks of heavy steel to practice welding together.