Popular Woodworking 2008-11 № 172, страница 8
-Letters- (ONTINUfO FKOM PAt if 14 additional moisture). This is alsoagood reason to allow materials to acclimate for a week or two to your shop's environment prior to milling. Are you millingstockfrom a thicker board and flipping/aces asyou mill so as not to remove the bulk of the material from any one face? If you take the majority of the waste from one face you open the stock to areas of unequal moisture content because the middle ofa board is higher in moisture than the outer surfaces. As that stock dries it can cause the piece to cup. This compounds if you're attemptingtobookmatch pieces resawn from 8M stock, so after you make a bookmatch cut,you need to allow the pieces to acclimate before milling to yourfinal dimensions. The trick is to begin the millingprocessbut then wait for a time before going toyour final thicknesses. Allow the material to rest for a few days, then finish milling by working the pieces as you would normally. Finally, I would look at the amount of clamp pressure you're using as you glue the panels. You needonly enough pressure to close thejoint. Further pressure adds stress to the wood which can, after 24 hours in clamps, cause the pieces to distort. All in all, you shouldn't have problems if you follow these guidelines. Give them a try and see if they help. — Glen D. Huey, senior editor Overcome Slop in Biscuit Joints I have been struggling with my biscuit joiner and have nearly given up. But 1 re-read your article from the February 2007 issue (#160) and a glimmer of hope remains. 1 originally bought the biscuit joiner to try to straighten up longer boards for glue-ups. However, there was so much slop in the (it that there was no way the biscuits would line up the boardsand hold them. The biscuits moved up and down V2" or so. 1 think I was making all of the mistakes possible and some that didn't seem possible. I was even thinking of gelling bac k i n to l he dowe 1 i ng t hi ng aga in. — Ira B. Rothenhoefer, Clubb, Missouri The slot should be tight in the thickness of the biscuit. The biscuits can swell and shrink with changes in humidity, but generally they can be pushed in by hand or you might need a light tap with a hammer. Going the length of the biscuit,you'll be able to move them back and forth, depending on the depth setting of the machine. If they are as sloppy asvou describe, there is definitely a problem that could be the machine, its cutter or your technique. The first thing I would check is the cutter. It's possible (but not likely) that a tooth is bent, resulting in a wider than normal slot. A more likely problem is the plunge mechanism of the tool. It should move smoothly in and out, without any up-and-down movement. The last thing to look at is your technique. If you tilt the machine as you plunge, the slot will be wider than it ought to be. Hold the fence down firmly, lock your arms and try pushing withvour legs and body. It's easy to introduce some swing into the motion if you try to use your hands and arms alone. — Robert W. Lang, senior editor Latex Paint Blocking Woes I painted an entertainment center with interior latex semi-gloss, and I am havinga real problem with blocking, which makes the doors stick. To stop the sticking, can 1 topcoat the edges of the doors with shellac and then poly-urethane? I'm very frustrated-and 1 should have stuck with milk paint. — Terry Kelly, Presque Isle, Maine you're right that latex paints "block" - that is, stick. It's one of the really big downsides of latex paint that no one talks about. One suggestion would be to apply wax to the doors, but it may not work for longand it will have to be reapplied now and then. This is the easiest thing to try, though. Your idea of shellac and polyurethane sounds fine to me, but that's a lot of work to do to the entire cabinet. I wonder if you can simply coat the door edges. Also, 1 don't see why you'd have to use both shellac and polyurethane. Why not shellac alone or polyurethane alone? Or what about coaling the edges with an alkyd paint or milk paint of the same color and sheen? If you do try the wax first, thenyou'll have to remove it very well with mineral spirits or naphtha before applyingpolyurethane or paint. In this case I would begin with the shellac because it may be difficult to get all the wax off. See if the shellac works by itself There's also a white-pigmented shellac called BIN if the project is painted white. The problem with all these suggestions, except the wax, is that you're building thickness, which makes rubbing more likely. Socontinuing to think out loud, why not try wax on one door and see if it works. If it doesn't, clean it off as good as possible and apply a thin coat of shellac or BIN. I've heard of adding cornstarch or talcum powder to latex paint to prevent the blocking, but I've never tried it, so I can't tell you how much to add or if it works. But it makes sense to me that it could. — Bob Flexner, contributing editor Omnijig Review Clarification In our review of the new 24" Omnijig in the August 2008 issue (#170) we staled that additional bits were required to cut dovetails in material other than V-i" thick. Actually, the dovetail bit included with thejigallowsyou tocul dovetails in any thickness up to 3A". pw Question? Comment? We want to hear from you. Popular Woodworking welcomes comments from readers about the magazine or woodworking in general, as well as questions on all areas of woodworking. We are more than happy to share our woodworking experience with you by answering your questions or adding some clarity to whatever aspect of the craft you are unsure about, and if you have a complaint, we want to address it whenever possible. Though we receive a good deal of mail, we try to respond to all correspondence in a prompt manner. Published correspondence may be edited for length or style. All correspondence becomes the property of Popular Woodworking. Send your questions and comments via e-mail to popwood@fwpubs.com, or by mail to: Letters Popular Woodworking 4700 E. Galbraith Road Cincinnati, OH 45236 16 ■ Popul ar Woodworking November 2008 |
