i've got a cheap chinese bass in my garage i'm gonna be doing up, there is nothing wrong with it except a long crack running vertical right down the centre of the top. it starts about 3 inches above the saddle and ends about 3 inches above the end of the fingerboard. it is right through the wood for about 15 inches in the middle (under the bridge). as it's not really worth taking to a luthier i wouldn't mind some diy crack tricks. cheers