Tennessee Valley Woodworkers

Tennessee Valley Woodworkers

Vol. 12/ Issue 11 November 1998 Editor: Tom Gillard

Meeting Notice:

The next meeting of the TN Valley Woodworkers

will be held, November 17, 1998 at 7:00 p.m. in the

Duck River Electric Building, Decherd, TN

All interested woodworkers are invited!

The question was ask at the October meeting as to how much the club made from the auction that we had at this years picnic. (see minutes)

We made $277.00 at the auction, the expenses for the picnic were $135.57, leaving us clearing $141.43. The balance in the treasury is $457.52, this should be enough to cover our expenses for the remainder of the year and give us a good start for next year.

Thanks to all you that participated in the auction, both by donating and by bidding.

We have a celebrity among us - Doyle McConnell. Foothills Crafts in Manchester was featured in the TENNESSEE section of the November issue of SOUTHERN LIVING. Doyle not only got his name and work mentioned, but there is a picture of him turning also. Believe he must have been at the right place at the right time. The article will be at the November meeting if you have not seen it, be certain to read it. What's next Doyle, the cover of FINE WOODWORKING?

Jimmy Burr from Manchester, Jimmy carves (or whittles) canes and walking sticks.

Dick Binger from Huntsville, Al. Dick presented our program in January showing us how he made his beautiful segmented bowls.

John Doolittle from Tullahoma, John will be out of town until early next year, but hopes to attend our meetings upon his return.

Milos and Rose Wilson from Estill Springs, Milos carves caricatures and Rose paints them.

Bob Reese reported that the Coffee County Fair was excellent. The club had a display and demonstrated lathe work. Doyle McConnell stated that the fair committee was happy with the clubs participation.

Carving seminar - Steve Graham reported that there were 18 in attendance. Benny’s Woodworks had a display. Richard Gulley prepared lunch. There was only one minor accident.

New business - The Christmas party is scheduled for Saturday, December 5th at the Nazarene Church in Decherd. It is set for 5:30 start with the potluck meal at 6:00 PM.

Tom Gillard - a Kauai wood bowl, a covered bowl, a ruler with 14 different wood samples and key rings all brought back from New Zealand by his wife.

Loyd Ackerman - a cherry board aged with a lye solution and two fluted candle holders - one finished with danish oil and one treated with the lye solution. Tom Cowan - a walnut oil lamp and a carved bowl with lid in either teak or rosewood.

Henry Davis - a small chair to demonstrate angled mortise and tenon joints, a carving from the seminar and a four way tapered leg jig.

John Troxler - a variety of old tools including a ball peen hammer, three back saws, square hole saws, scraper and gent saw.

After a short break Jack Busby from Minnesota Mining and Manufacturing (3M) presented a program on sanding.

The program for November is a presentation by Dr. Ben Spalding of Manchester on "Investment Castings". This program should be interesting to everyone in the club, and of major interest to the carvers. Dr. Spalding is an experienced carver and uses these techniques in preparing the castings he makes.

Years ago at a garage sale, I bought a pile of no-name sandpaper for just pennies a sheet. I got it home. I sanded with it, but nothing came off the wood. Sanding harder, the grit came off the paper. It didn't even burn very well in my wood stove.

Sanding is necessary drudgework, improved only by spending less time doing it. As I learned, you can't go right buying cheap stuff, but it's still easy to go wrong with the best sandpaper that's available. Not long ago, for example, I tried to take the finish off some maple flooring. Even though I was armed with premium-grade, 50-grit aluminum-oxide belts, the work took far too long. It wasn't that the belts were bad. I was simply using the wrong abrasive for the job. A 36-grit ceramic belt would have cut my sanding time substantially.

The key to choosing the right sandpaper is knowing how the many different kinds of sandpaper work. Each component, not just the grit, contributes to the sandpaper's performance, determining how quickly it works, how long it lasts and how smooth the results will be. If you know how the components work together, you'll be able to choose your sandpaper wisely, and use it efficiently. Then you won't waste time sanding or end up burning the stuff in your wood stove.

What sandpaper does to wood is really no different from what a saw, a plane or a chisel does. They all have sharp points or edges that cut wood fibers. Sandpaper's cutting is simply on a much smaller scale. The only substantial difference between sandpaper and other cutting tools is that sandpaper can't be sharpened.

Look at sandpaper up close, and you'll see that the sharp tips of the abrasive grains look like small, irregularly shaped sawteeth. The grains are supported by a cloth or paper backing and two adhesive bonds, much the way that sawteeth are supported by the sawblade. As sandpaper is pushed across wood, the abrasive grains dig into the surface and cut out minute shavings, which are called swarf in industry jargon. To the naked eye, these shavings look like fine dust. Magnified, they look like the shavings produced by saws or other cutting tools. Even the spaces between the abrasive grains serve an important role. They work the way gullets on sawblades do, giving the shavings a place to go. This is why sandpaper designed for wood has what's called an open coat, where only 40% to 70% of the backing is covered with abrasive. The spaces in an open coat are hard to see in fine grits but are very obvious in coarse grades.

Closed-coat sandpaper, where the backing is entirely covered with abrasive, is not appropriate for sanding wood because the swarf has no place to go and quickly clogs the paper. Closed-coat sandpaper is more appropriate on other materials such as steel and glass because the articles of swarf are much smaller.

Some sandpaper is advertised as non-loading, or stearated. These papers are covered with a substance called zinc stearate--soap, really--which helps keep the sandpaper from clogging with swarf. Stearated papers are only useful for sanding finishes and resinous woods. Wood resin and most finishes will become molten from the heat generated by sanding, even hand-sanding. In this state, these substances are very sticky, and given the chance, they will firmly glue themselves to the sandpaper. Stearates work by attaching to the molten swarf, making it slippery, not sticky, and preventing it from bonding to the sandpaper.

The backing's stiffness and flatness influence the quality and speed of the sandpaper's cut. For the most part, manufacturers choose adhesives and backings to augment the characteristics of a particular abrasive grit. You will have a hard time finding an aggressive abrasive mineral, for example, on a backing suited to a smooth cut.

The stiffer the paper, the less the abrasive minerals will deflect while cutting. They will cut deeper and, consequently, faster. Soft backings and bonds will allow the abrasives to deflect more, giving light scratches and a smooth finish. You must even consider what's behind the backing. Wrapping the sandpaper around a block of wood will allow a faster cut than sanding with the paper against the palm of your hand. For instance, an easy way to speed up your orbital sander is by exchanging the soft pad for a stiff one. The other consideration is the flatness of the backing, which has nothing to do with its stiffness. Flat backings position the minerals on a more even level so they cut at a more consistent depth, resulting in fewer stray scratches and a smoother surface.

Cloth is the stiffest but least-flat backing. It will produce the coarsest and fastest cut. Cloth comes in two grades, a heavy X and a light J. Paper is not as stiff as cloth but it's flatter. It comes in grades A, C, D, E and F (lightest to heaviest). A-weight paper that has been waterproofed is approximately equivalent to a B-weight paper, if one existed. Polyester films, including Mylar, look and feel like plastic. They are extremely flat and pretty stiff. They will give the most consistently even cut and at a faster rate than paper.

The backings for hand sheets and belts are designed to flex around curves without breaking. This is not true for sanding discs for random-orbit sanders. They are designed to remain perfectly flat, and if used like a hand sheet, the adhesive will crack off in large sections. This is called knife-edging because the mineral and adhesive, separated from the backing, form knife-like edges that dig into and mark the work.

Adhesive bonds on modern sandpaper are almost exclusively urea- or phenolic-formaldehyde resins. Both are heat-resistant, waterproof and stiff.

Hide glue is sometimes used in conjunction with a resin on paper sheets. It is not waterproof or heat-resistant, but hide glue is cheap and very flexible.