J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Drying Balsa Core with Vacuum and Heat

After corresponding with Chris Tate about some approaches to this crazy project I decided that I would first go out and test removal of the bad balsa core in small sections that matched the block sizes of the new balsa core I have. At least in the new balsa I have the block sizes are fairly consistent, so I thought if I removed old bad balsa in similar sizes that would make the process more manageable. So I marked out some sections and then got my tool arsenal together. First was a normal small die grinder with a very course burr. Second was the right angle die grinder. Third was the new impact chisel. Fourth was a small router with a 1/4" spiral bit.

The die grinder with the burr gobbled through the bad balsa and got to the inner skin quickly and easily. It was easy to control and didn't want to chew into the inner skin. It did slow down dramatically when it was trying to remove the good balsa inside the patch I was trying to work.

The impact chisel could cut the outer skin easily, peel it and then lift the balsa away from the inner skin easily as well. You had to be a little careful at the perimeter of the patch so as to not damage the adjacent balsa. It liked working the larger patches more than the smaller ones because you can get lower angles.

The router was good at cutting a nice perimeter edge, but it was a challenge to see what was going on. This tool would be good for establishing the perimeter, but very tedious to remove large patches and for sure a screw up could quickly puncture the inner skin.

The small right angle die grinder with a 2" abrasive pad was great for cleaning up the inner skin, but is not overly powerful and stalls easily. But it would be the right tool for working these kinds of patches.

So I worked several of the patches that I marked out. The bulk of the material removal went fairly quickly. The time started going up as I worked the edges trying to square them up so they could receive a new balsa plug. But and this is a big "but" what I noticed with the die grinder burr was that in several places the soft/bad balsa dove down closer to the inner skin and likely continued some unknown distance. So the area that was marked out on the top surface didn't necessarily include all of the bad balsa.