Tennessee Valley Woodworkers
Vol. 19/ Issue 8 August 2004 Editor: Tom Gillard Jr.
The next meeting of the TN Valley Woodworkers
Will be held, August 17th at 7:00 p.m. in the
Duck River Electric Building, Dechard, TN
All interested woodworkers are invited!
The following people have agreed to serve as contacts for their particular skills. If you have questions, suggestions for activities, or other comments relating to these skills, please call these folks. Their interest is to help the club better serve their area of expertise. Your participation with them will help them achieve that goal.
Tom Church 967-4460 Turning Harry May 962-0215 Carving
Bob Reese 728-7974 Sharpening Ross Roepke 455-9140 Jointery
Maurice Ryan 962-1555 Health and Safety
List of Club Officers
Sept. 19-24: Coffee
(click above to see features)
Bob Lowrance had two carvings, a cowboy cardholder and a lady dulcimer player. They both were modifications of another carving pattern he had.
Tom Cowan had photos of his latest creation, an entertainment center that he had designed and built for a client in Nashville. He discussed the design and build process.
Bob Leonard had a small flag holder that he had made from an eagle that came off a flag poll. He had fabricated a base for it from spalted maple.
Tom Few had three turnings. A vase from cedar firewood, a mulberry lidded box and a purple heart bowl. These were his first turnings. I believe he is hooked.
Ross Roepke had a carved cypress stump bowl that he had bought at a craft show. He also had two business card holders that he had made from a pattern in Wood magazine.
Loyd Ackerman brought two:( 1 & 2 ) segmented vessels and a spalted maple bowl. The process for the segmented vessels was learned at the Provo woodturning symposium he recently attended. He invited the club to come to his home and get maple bowl blanks that he has stored in his yard.
Drew Sevelle had a nice sword that he had made. It had a very nice laminated handle on it.
Bob Reese had a column that was part of a scale model church building that was to be the collection box for the church congregation.
Harry May brought a large carving of a Navaho woman with a water jug. The carving was from cherry wood.
Newt Wright brought a segmented bowl
that he had made from end cuts of pine 2X4’s. He discussed how difficult
it was to turn the end grain segments. Nice job Newt.
Sand bare wood to 180- or 220-grit -- For sanding bare wood, 180-grit will generally give you a surface that looks and feels perfectly smooth and is ready for a finish of some kind. Sanding the surface with a finer grit is only necessary if you're going to use a water-based finish. These finishes will pick up and telegraph the smallest scratches. Sanding the wood to 220-grit or finer will prepare the surface better. However, it's not always wise to sand to a finer grit. You will waste your time if you can't tell the difference, and you may create problems in finishing. Maple sanded to 400-grit will not take a pigmented stain, for example. Pigments work by lodging themselves into nooks and crannies on the surface; without them, they will have no place to stick.
Sand faster across the grain -- How many times have you been told never to sand across the grain? True enough. The scratches are much more obvious, look terrible and are hard to remove with the next finer grit. But what holds true for planning wood is also true for sanding. You will plane and sand faster and more easily when the direction of your cuts is between 45° and 60° to the grain, because the wood-fiber bundles offer the least resistance to the cutting edges. Cross-grain scratches are harder to remove simply because they are deeper.
Use a combination of cross-grain and with-grain sanding to get the smoothest surface in the fastest manner. First make passes at 45° to 60° to both the left and the right, making an X-pattern on the workpiece. Then, with the same grit, sand with the grain to remove the cross-grain scratches. Do this with each grit when belt-sanding and hand-sanding. The non-linear sanding action of random-orbit and orbital sanders can't take advantage of the wood's grain properties. When I use my orbital, I just sand with the grain.
Choosing from the four abrasive minerals
Four common abrasive minerals are aluminum oxide, silicon carbide, ceramics and garnet (see Four abrasive minerals). Except for garnet, they are all manufactured, designed if you will, for different cutting properties. Harder and sharper minerals cut deeper scratches and, consequently, sand the wood faster. But these deep scratches leave a coarse finish, whether you sand with or across the grain.
Softer minerals within the same grit size will cut far more slowly but leave a smoother finish. For example, if you sand a board on one side with a 120-grit ceramic, the hardest abrasive mineral, and the other side with 120-grit garnet, the softest, you will be able to feel a distinct difference between the surfaces. It will seem as if you sanded the two sides with different grit sizes.
It's easy to rate each mineral's hardness and sharpness, but it's not as simple to prescribe specific uses beyond generalizations. There are many other factors that influence the appropriateness of a sandpaper for a job.
Some fine points about grading scales
If you don't mind that we have two measurement systems, the U.S. Customary (foot, gallon) and the International (meter, liter), then you won't mind that we have three major abrasive grit-grading systems. In North America, the Coated Abrasives Manufacturers Institute (CAMI) regulates the U.S. Standard Scale. CAMI-graded sandpapers simply have numbers, such as 320, printed on them. The Europeans have the P-scale, regulated by the Federation of European Producers Association (FEPA). These abrasives are identifiable by the letter P in front of the grit size, such as P320. Finally, to make sure everyone is really confused, there is a totally different micron grading system. This system is identified by the Greek letter mu, as in 30µ.
The three systems grade particle size to different tolerances but by the same methods. From the coarsest grits up to about 220, particles are graded through a series of wire mesh screens. The smaller grit sizes are graded through an air- or water-flotation process that separates particles by weight.
The chart is helpful in comparing grits of the three grading systems, but it doesn't tell the whole story. Abrasives on the P-scale are graded to tighter tolerances than CAMI-graded abrasives. This means that the CAMI-scale tolerates a wider range of grain sizes within the definition of 180-grit than the P-scale. Tolerances are even tighter for micron grading. P-graded and micron-graded abrasives give more consistent cuts with fewer stray scratches from outsized minerals.
Micron-graded abrasives on polyester films are about three times as expensive as paper products and probably not worth it for sanding wood. I have a hard time telling the difference between wood sanded with a 100µ finishing film abrasive and standard 120-grit sandpaper. But for polishing a high-gloss finish, I find micron-graded abrasives make a substantial difference.
On the Baltic Sea's northern shores, where ash once grew thick and tall, ancient Scandinavians called the tree Yggdrasil. Its branches were said to hold the gods, its trunk their path to earth, and its roots the way to the underworld.
American Indians pounded "basket ash" to soften it for peeling into weaving strips. Canoe paddles were made from it, as well as tomahawk handles and spear shafts.
Today, the handles of many picks, shovels, rakes, and axes are made of ash. It also may be the most sporting wood around, the mainstay in laminated-wood tennis racquets, hockey sticks, and skis. Baseball bats always have been made of ash because of its ability to absorb shock, bend without breaking, and add heft without unwieldiness.
These uses, combined with its popularity with furniture makers, place ash among the commercial hardwood leaders.
See you on the 17th.
Donations to the club have been made by these companies.