Dents and dings from building
My current project is just about ready to cover so it was time to take care of all the little nicks and dents in the balsa that come from handling the plane on the workbench. Usually these just get filled with putty but there's a method you can use to lift the majority of them first. I mentioned this method at the field and most people had never heard of it so I thought I'd mention it here. It's an old woodworker's trick.
Steam will pop most of those dings right back out. Using a clothing iron set hot enough to steam, if you wet the ding and then place the iron on it you'll hear the water sizzle. When the water is steamed out, remove the iron and like magic, the dent is gone. Larger dents may take several applications and some just can't be lifted. That's okay, now you have fewer that need filler. I always check the spot to see if it needs an additional application and frequently I can't even tell where the dent was in the first place.
I used to lay a wet paper towel over the area and iron it dry but lately I just use the wet paper towel to soak an area and then just steam the whole area out. The grain will also be raised and the surface will need a light sanding but it's a great way to prepare for filling and final sanding.
Just be sure that the steam is compatible with the adhesives you have used in construction.
Dave