Woodworker's Journal fall-2010, страница 74
Questions & Answers QMy battery shelf has the common 'Triple-A," "Double-A," "C" and "D" size batteries on it. But, there aren't any "size B" batteries. Why? Sherwood Elkind Englewood, Colorado Just like the pop-top soda can, bell-bottom jeans and 3/8"-shank router bits, battery sizes are somewhat driven by popular demand. As it turns out, there used to be a size "B" battery, but not enough consumer goods made use of it, so stores stopped carrying it. Consequently, it's not around in this country anymore, although it's still available in Europe. Chris Marshall QWhen I use my pneumatic nailer, I'm not sure how much nail/brad depth is sufficient to securely hold two pieces together. How do you calculate the gauge/length versus the thickness of the wood to ensure secure attachment? Amy M. Nielsen Maple Valley, Washington A A good rule of thumb is to use nails that are three times as long as the thickness of material you are joining. For example, if you are securing a 3/4"-thick board, you would want to use a 2!4"-length fastener. If the thickness of the substrate to which you are fastening your board won't allow for this length, add the thicknesses of the two boards you are securing and then subtract 1/4" to allow for countersinking. A general guideline for fastener gauge would be to use a 15- or 16-gauge fastener with 5/8"-thick or greater stock, an 18-gauge fastener for 1/4"- to 5/8"-thick stock and a 23-gauge pin for stock a 1/4" thick or less. Typically the lower the gauge, the better the holding power, but this larger fastener can sometimes cause splitting — dependent on how close the fastener is to the edge of the board and the species of the wood itself. The best thing to do is to run a trial with some scrap pieces of wood to determine what size works best. Gary Blanchette and Dr. Edward Suit (Stanley-Bostitch) r W m Nailer depth setting vs. the thickness of your wood: A good rule of thumb is to use fasteners three times the thickness of your wood. QI want to coat some bunk beds and need to know how much finish to buy. When finish makers state that the coverage is X square feet per gallon, and that one should use at least three coats, does this mean that the gallon will cover X square feet three times or just once? David Minehart San Jose, California A Just once. A claim of 400 square feet of coverage per gallon means there's enough to cover 400 square feet once. For three coats of 400-square-feet coverage, you will need three gallons. However, coverage numbers are only average guidelines, and the amount of coverage you get can vary greatly, depending on three major factors. The first is the substrate. A very porous piece of wood will absorb, and consequently use up, more finish than a coat applied to a denser wood or to an already sealed surface. Thus, when working with porous woods, odds are good that on the first coat, you will use more finish and get a lower area coverage rate than on the second coat. The second variable is your application method. Brushing wastes almost no finish: nearly 100 percent of the coating in the can will end up on the wood. However, spraying wastes anywhere from 35 percent to 75 percent of the finish, resulting in far lower coverage rates. The third variable is you. What you call "one coat" may be much thinner or thicker than what the next guy calls "one coat." Thus, your coverage per gallon may be much more or less than the company estimates on its can. Michael Dresdner Calculating finish coverage is an equation that includes a few variables. 74 Questions 8c Answers |
