Howdy everybody and Happy Easter to anyone who celebrates it. I had wanted to answer Jenny's question about voids in plywood a couple days ago but couldn't find the time. Luckily, I had to cut a notch in the end of a piece of plywood the other day, which gave me the perfect opportunity to take a photograph of what I'm talking about.
Over on the right you can see the back of a piece of plywood. This is a piece of A-C plywood. The A and C refer to the quality of the surface of the plywood. One side of this plywood-the A grade side-comes sanded and with all voids filled, ready to paint. The back is C grade, which is a lower grade. You can see the voids and unfilled cracks in the photo. It is also not sanded on this side. (More plywood grading info here.)
To the right you can see where I've begun to chip away, exposing the different layers or plys that give the sheet it's name. Each ply has the grain running perpendicular to the layers above and below it. This is what gives plywood it's uniform strength. Usually, these layers are harvested by shaving a layer off the tree as it is spun on it's long axis. You can see evidence of this process when you look at the face of a sheet of plywood and see the same grain pattern repeating itself over and over. Every time the shaved layer hits a knot, that hard, center portion of the knot can fall out, leaving a hole-or void-in that layer. Depending on where the plywood sheet is cut, the finished edge of the plywood might contain part of that void. This means one would have to fill and sand it before painting, and would pretty much disqualify it for clear coating.
In other news, the "Grand Theft Autoclave" team tied for second place in the Pete's Candy Store weekly trivia challenge, which was good for a $17 bar tab ("PBR's for everyone!") and qualification for the SuperBowl of Trivia, some months away. Trivia Tip: I have found that if you are willing and able to quickly and legibly fill out the answer sheet, nobody brings up your lack of good answers.
As another side note, I finally got around to watching Obama's speech on race and was glad I did. I find myself stunned when any of the three candidates speaks publicly. Each of them reminds me that it was once okay to have coherent, complicated ideas as a politician and to be able to express them. Obama, though, clearly takes it to the next level. I also agree with him, which helps...
I never thought I'd support someone who did not specifically utter the words Universal Health Care, but after some of the quotes that came out of the executive this week, I'm just getting all fluttery for someone who stands up and starts speaking and actually does not make my blood actually boil.
(If you don't have a lot of time, I think the best stuff starts about 15 minutes in.)