Keep going. I replaced a drum and bearings on a BC1000 year and a half ago and that cost me $6K. The 1800 has a much larger drum and bearings. I'd say more like $8k-$10K.
The damage does seem to be a rarity. I don't understand why an internal weld would go other than it wasn't welded properly to begin with. There are hndreds of welds in a machine and many of them along wear areas. Inside the drum isn't a wear area.
