To Cut or Not to Cut; That is the Question: from WoodCentral
"I put the last coat of finish on my dining table. After sanding and polishing, I will have approximately four coats of polyurethane on the top and bottom. My breadboard ends are flush to the tabletop, meaning there is no micro bevel or other such rounding between them to act as a separator. That said, should I make a cut with a razor knife or other blade to slice through the finish at this interface? As we all know, the table will move due to moisture changes, and I am thinking that the finish that passes over this joint could get pulled and maybe fracture in an unfavorable way.•bCrLf — Erick
We were sure there would be proponents of his suggestion, but were surprised at the responses. — Editor
"That is a good question and one you may have wanted to consider before the finish went on. Since you have two different grain directions, some movement is hard to avoid. I think this type of crack in the finish, if it happens, will follow the line of least resistance and fracture along the joint, which I think is more normal-looking and nicer to the touch than a knife cut.•bCrLf — Fred
"I built a breakfast room table out of cherry several years ago. I used several coats of a wipe-on polyurethane. I did nothing to the breadboard end joints, and it has never been a problem. Unless your coats are very thick, I wouldn't think it would be a problem. Mine moved immediately upon delivery to the breakfast room from the shop. The shop is heated and cooled, so I assumed the humidity would be similar, but it wasn't!•bCrLf — Tony
"Even with wood that moves a lot like spruce and fir, I've never had a problem with the finish at the breadboard edges. I agree that a knife cut will be quite noticeable. Leave it alone and you'll be fine.•bCrLf — John
Dark Matter: from WoodCentral
Not all questions are of equal import, but this one, while merely feeding curiosity, certainly generated fascinating explanations. — Editor
"I'm certainly not a chemist, but I do not understand why when I polish my table saw using Johnson® Paste Wax it turns my cloth black. The saw is clean. I use a soft wire brush on my drill to make sure I get any wood residue off, then I wipe it down with a dry cloth. When applying the wax, it turns my T-shirt applicator black. Probably not a big deal, but I wonder why this happens.•bCrLf — Terry
There were some serious answers, of course. — Editor
"The black stuff is metal. Since cast iron is rather soft, there's just enough abrasive in the rag to take off a small amount of the metal, and the wax makes it cling to the rag. Same thing happens when you polish silver or brass.•bCrLf — Rob
"You are probably seeing nothing more than the organic solvent in the wax dissolving and pulling off normal dirt and grime that accumulates on the surface.•bCrLf — Jim
"It is the graphite in the cast iron that is released when you abuse the surface with the wire brush.•bCrLf — Jesper
However, there was a far more entertaining answer offered as well. — Editor
"It is quite simple, really. The cloth absorbs the darkness from the saw's tabletop. You see, the darkness creeps into the saw during the night when all the lights are turned off. During the day, there really isn't enough light to remove all that darkness from the night before. So the darkness collects, and we must periodically wipe that darkness off using a cloth. The cloth absorbs the darkness from the saw's tabletop. The alternative is to leave the lights on all the time, or at least use a small nightlight in the corner of the workshop. Either that, or take the saw outside into the sunshine on a daily basis, which is really only an option in places like San Diego, Miami and Las Vegas, and not in Seattle, Portland, Bangor or Juneau. And since we're on the topic, make sure you dispose of the cloth properly. A cloth or T-shirt that has absorbed darkness can be dangerous. Properly disposing of them is important, yet is as simple as digging a six-foot hole in the ground (four feet if within the perimeter of a cemetery) and burying them with seven cloves of garlic.•bCrLf — Mark