Repairs and Setup
Any resonator guitar has to be set up properly to play and sound its best. With a little tweaking in the right places even an entry level, mass-produced, inexpensive instrument can be significantly "awakened". Many high-mileage reso guitars will benefit from a tune-up as well.
Filling and leveling imperfections in a soundwell like the one above ensures even contact of the entire rim of the cone, which will let the tone ring out...
Leveling the spider legs is also necessary for good, even contact...tone, volume, sustain...that's what it's all about!
The above is a excerpt from a posting by Martin Vasquez, as published on the Resonation and ResoHangout forums. Thanks Martin!
String slots need refurbishing in nut and bridge inserts, sound well or tone ring surfaces need truing, cones need the right amount of break angle over the bridge inserts for proper loading and so on.