ray, i just use a regular tea kettle and slowly move the surface a couple of inches above the steam. i move it at about 1 inch/second but sometimes i'll momentarily pause the surface over the steam if the dent is deep/large. keep in mind that if the surface has been cut, gouged or punctured then steam is not going to help. only where the balsa has been "flattened". another method is to apply a damp cloth on the surface and use an iron to create the steam.