I got one of varustelekas metal wood stoves two weeks ago. I've used it twice once with damp wood in a small fire and the second time with seasoned stuff on both occasions it didn't get very hot but creaked and appears to have warped quite a bit .Am i doing something wrong ? I can still use it but I don't know if i should keep using it .The bottom also has developed a bump. Does anyone else have any experience with these?