Band-sawing a rocker in a 12" wide piece of balsa? Wow… You were looking for trouble…
I’m glad for you that it turned out OK. I would never have attempted to do that.
As Jim said, I did hear the belt slip a little when I took a deep cut. It was fun mowing through the wood, and sending chips flying all over my shop. It soon became apparent, however, that it was going to take a long time to cut out the nose and tail rocker curves. I also wondered if I would ever be able to match the lines that Bill had drawn out for me. After some thought I decided that it was time to put away the planer, and break out the band saw. I had a riser block in a box on a shelf, and I had never gotten around to installing it. Today was the day to finally do the installation. It turns out that the maximum cutting height is a little over 12 inches, and my glued boards were just under 12 inches. I spent some time tuning the saw, and made sure that the blade was perfectly 90 degrees to the table. You can see my setup below. Everything worked out great. I’m happy with the way it looks so far.
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Band-sawing a rocker in a 12" wide piece of balsa? Wow... You were looking for trouble...
I'm glad for you that it turned out OK. I would never have attempted to do that.
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Hahaha... yes I know it was risky. I'll probably do it the way that has been suggested above on my next board. It was a mistake to glue the boards together before cutting then to the shape of the rocker.
I did a bunch of test cuts beforehand, and used the bubble level to make sure that everything lined up perfectly. At first I was just going to do a few rough cuts to just get me close to the line. I had a new saw blade, and it cut the 12" thick balsa like butter. When I examined my first pass I noticed that it was in perfect alignment. I learned from doing my test cuts that you have to go slow when making a turn, or the blade will bow out. I started getting more confident as I made more perfect cuts, and I brought the blade in closer to the line. The next thing I knew the whole thing was cut to within an eighth of an inch from the line. The nice thing about doing it this way is that my top an bottom deck lines are nice and parallel now. It is currently three and a quarter inches thick at the thickest point.
I'd have to wait until one of the real experts (Jim Phillips comes to mind) chimes in, but bandsawing 12'' at a time seems like a good idea if you can be accurate - looks like you were. I've watched Jim wrestle 6 or 7, or 10 or 12 with redwoods thrown in, pieces of wood into bar clamps for glue-up; it can be a strenuous and difficult activity keeping everything lined up. You've eliminated a lot of that.
I see no problem with sawing 12inch thick balsa on a bandsaw. Just have to have the right blade, proper tension and good table. I have no problem with it. On harder woods I prefer a max of 8 inches.But then I am a wood worker.
Swied--------What brand of bandsaw is that. I like the looks of it. I'm going to have to buy one soon as I have a bunch of of blanks to stringer. Looking for something with a wide cut (18") and the ability to cut stock that is 5 or 6" thickness. Got to be reasonably priced though.
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I see no problem with sawing 12inch thick balsa on a bandsaw. Just have to have the right blade, proper tension and good table. I have no problem with it. On harder woods I prefer a max of 8 inches.But then I am a wood worker.
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The man is absolutely right. Added emphasis mine.
The right blade: Sharp, with the right tooth shape, tooth spacing, width, thickness and set for the wood you're gonna cut. Not the Home Depot special-of-the week crap blades, but a really good one. I'll reccommend http://www.timberwolf1.com/ from personal experience. The right blade for the job makes a big difference, the wrong blade makes it impossible. They are fairly cheap, bandsaw blades, much cheaper than ruined wood. Don't hesitate to replae as necessary
The right tension: Not too tight, not too loose. http://www.timberwolf1.com/six_rules.asp will tell you how, so I don't have to.
A good table: Tightened properly, set right, the adjustable square is your friend here.
Additionally:
Tune your saw. Blade guides should be nice and flat on the ends, spaced correctly. If you have a nice set of ball-bearing guides, you're laughing, but those might want to be checked anyhow.
Wheel bearings - if somebody left the tension on for any length of time, the bearings can develop flat spots. A Dial Indicator can help there.
The various nuts and bolts should be appropriately tight too, all the way down to allen set screws. Refer to your manual, many are online at the maker's websites. The manuals for the oldies that I like may be at http://www.owwm.com/ . You'd be amazed what can vibrate loose/funny over time.
Bandsaw tires get worn out or slip. Again, they are fairly cheap to replace.
A properly set-up band saw is a delight to use and as accurate and precise as anything in a wood shop (though not a patternmaker's shop) , an out of tune bandsaw with a cheezy blade and crummy guides is a misery.
Hope that's of use.
doc...
It’s a 14" Powermatic with a 1.5 hp motor. It does the job for me. I know that most pro woodworkers would say that you need at least 3 hp if you are going to do a bunch of resawing. Those saws cost a lot more money though. My Powermatic is nice because it has the roller bearing guides, which are normally only found on more expensive saws. It also has a dust collection port, but I still need to by an attachment. My wife was kind of pissed when she saw balsa dust all over the garage, since that is where our washer/drier is too.
I have learned a lot from reading the comments on this thread, and from making observations while I work on this project. Up above, WoodOgre mentioned that there was a lot of tension stored up in balsa wood. When I was cross cutting one of the end sections of a board I noticed that the board was deforming as I progressed. My pull saw became harder and harder to work. I made another cut closer to the end of the board, and didn’t have the same problem.
It is also amazing how well these boards glue up with a good bit of clamping pressure. I believe that all my wood was milled straight, and even before I purchased it. Because of the whole internal stress thing, they probably bowed imeadiately after exiting the saw. I’m glad that Bill gave me the advise to just leave the wood alone, and clamp it up naked. All of the joints are razor tight.
Here is an update of the progress that I have made so far.
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The bandsawed section that I posted pictures above turned out nice. When I stand back, and look at the curves on the deck and bottom, they look perfectly even.
I’m not sure what everyone else uses, but here is my secret weapon for sanding out bandsaw blade marks on the bottom rocker of the 12" wide section. The board is a 3/4" thick piece of melamine from the $2 bin at HD. I spray glued some 50 grit sand paper sheets to it, and then pulled it all the way along the board (wearing leather gloves of coarse). It made the rocker nice and smooth, and it didn’t take too long (see picture below). I made another more flexible sanding sled for the deck out of masonite, butI don’t have a picture of it.
Here is the right rail board glued to the pre shaped center section. I plan on using my Hitachi planer to bring the side rails down to the level of the center section.
Tonight I glued on the left rail board.
I made an interesting observations about the grain direction of my boards. Notice in the picture below that I drew lines on the ends to show the grain pattern. It is interesting that all four boards have exactly the same cup down grain pattern. I think this happened because I oriented the boards so that the “natural rocker” of all of them curved in the same direction. It looks like you could conclude that the convex side of a bowed board is the side that it closest to the center of the tree. I’m not sure how useful this information may be, but it is interesting none-the-less.
Aloha Swied,
Looks like you are doing things well an d getting the results you want. The great thing about Sway is that you can tap the brains from guys that have miles and years of experience. The advice from seasoned vets can save lots of heartache. I'm always amazed how so many will hear such advice, then do it "my own way" only to really regret it and pay the price later. Back in 1976 or so I had an 80 year old woodworking mentor tell me, "If you can't find the time to do it right, how will you ever find the time to fix it?" That quote stayed with me all these years. To this day I'll find myself out in the shop trying to do a short cut on on somethig only to remember Mr. Scriven's quote. I stop, smile, take my time, and do it right because I know he's always watching my work. I keep a picture of him above my bench.
Again, some great advice given in this thread from Doc, Jim, Woodogre, and others. You are smart to take heed. One extra tid-bit of info: Unlike hardwoods, I've found that you can cheat a bit with balsa when it comes to milling (jointing, etc.). Use the bandsaw for ripping to get as straight a line you can (straight edge, chalkline, whatever, to mark). Use roller stands or similar behind and in front of the longest bed jointer you have or can use. Take the time to shim and get them carefully set to not only the proper hieght to the infeed and outfeed ends of the jointer, but also side to side with the jointer. When jointing a 1" thick board this is not nearly as important as jointing a 4" + wide board. A few extra minutes to get this dialed in and right will pay off.
After you have run the first part of the board across the jointer blades begin putting your down pressure on the board over the outfeed table. I've seen so many guys, even experienced ones, start out with downward pressure on the infeed table and as they pass the board across the jointer they continue pressure on the board over the infeed table all the way through the entire pass. They don't even notice the light shining under the new edge out over the outfeed table as the board may spring up off the table even ever so slightly. Once the "new edge" has been milled as the board passes over the knives it is important to allow this to reference and establish the cut to come behind it. Back to the cheating thing...Balsa is so light and has enough flex (even thick boards) that if you can manage to keep the long end out in front of the outfeed table relatively straight (on the roller table or shimed and leveled saw horse), you can manhandle the long balsa board by putting enough pressure with body weight down on the outfeed table to get a perfect joint. A large or wide / thick hardwood board of six feet or more in length becomes very difficult to joint without a commercial longbed jointer. I have jointed long balsa boards perfectly by concentrating that downward pressure on the outfeed table out through the last few feet of the jointing process. One hand down on the the board applying pressure and the other hand way outstretched to hold the long end from tipping off the outfeed table. The slightest tip is a big oops here.
If it's a show board or wall-hanger you will want to bookmatch your boards and aesthetics is primary to wasting wood. On showboards, for example, you may rip a certain board lengthwise to get two equal halfs to go on either side of a stringer. If the board was bowed to begin with then each piece is bowed the same direction after you rip it down the center. You will therefore have to straighten and mill each piece flat which wastes a lot of wood. If it's not a showboard such aesthetics are not as important. You may think trade-offs and compomises when it comes to beauty vs time / efficiency, but I would suggest you never compromise your construction. Art vs science, the engineer vs the poet, function vs form....the debate always goes on. Find your own personal place in all that, but take the time to build it right and be proud of it. Enjoy the ride!
richard mccormick
Thanks for that tip. It makes a lot of sense to me. Which way do your orient your board when you do this: concave up or down? On my first balsa board I created a big pile of saw dust from my jointer. It took so many passes to get the boards straight. That is the main reason why I was so hesitant to touch the jointer on this board. When you say “manhandle” I am thinking that you need to put all of your weight down on the board when it goes over the outfeed table. I’m going to keep that in mind for future projects.
My primary reason for creating this board is to be able to ride it. I really like the way wooden boards ride. So far, I have completed a 6’ 2" chambered balsa single fin, and a 6’ 8" redwood HWS thruster. I don’t think that I mentioned it yet, but this is going to be a big wave board. It is going to be an old school gun 10 feet long, 22 inches wide, and will have a single fin. I am planning on glassing it with epoxy. I have both RR and KK. I haven’t decided yet which to use on this board.
Aloha Swied,
The "manhandle" thing may be a little overkill term, as I was just trying to make the point about keeping the long timber of wood straight with the emphasis on keeping the board flat on the outfeed table. Try your very best to get the board ripped straight as possible before going to the jointer. Sight down the length of the board to determine if there is a bow and where the high spots may be. If after ripping the board straight it may just bow a bit. You'll do much better with the bow up (concave down on the jointer table) if there is one. If so, run the front few feet of the board across the jointer until the knives no longer touch where the board begins the concave or cupped (hollow) area. Lift the board off the jointer, move it forward, then run the last few feet across the jointer. It may take a couple of passes on each end. Then run the entire board across the jointer in a long smooth pass with that downward pressure on the outfeed table. You'll hear the knives "buzzing" the wood. This sound will ease off when you hit hollow areas where the knives don't cut wood. After one or two passes you should hear the same uniform sound from one end to the other. You can draw a scribble chalk mark down the length of the board prior to running across the jointer, then check to see that the whole chalk line is erased by the cut of the knives after the pass through the jointer.
A slight bow won't be a problem when gluing up balsa because it will bend up rather easily when clamped. The trick is to keep it dead flat or with very minimal bow if possible. The rules are different when edge gluing up hardwoods for a cabinet side or table top for example, as the boards must be dead on perfect in order to get a perfect glue line. Any forced bend with heavy clamping will only end up separating at some future time.
Anyway, with a balsa blank there's not much of a reason to get too much into furniture grade overkill when milling the wood. Spend the time getting the rip line straight and you won't have trouble running it across the jointer and wasting much wood. AS Woodogre mentioned, some balsa can really move alot after ripping it. If it moves violently use the methods already mentioned in above posts by ripping and gluing up the opposite bends. I don't like edge gluing boards that bow out at the ends. Instead I prefer to pull up the middle with clamps which keeps the ends tight. The glue is super strong, but glued up boards are usually more likely to separate at the ends, especially since the nose and tail of the board are narrower than in the center.
I don't want to write a novel, but I think you get the picture. Be deliberate but keep it simple. You'll do great.
richard mccormick
With reguard to the anual rings on the end grain. As stated the boards will cup in the opposite direction of the rings. An old cabinetmakers/woodworkers trick to minimize warping, is to alternate the direction of the rings. One board with the rings facing up, the other facing down, etc., etc. The alternate cupping should cancel out itself. You’re grain pattern won’t look as nice though.
Aloha surfifty,
Very true on the annual rings / cupping. Cupping occurs across the face of the baord (across its width) which will not pose a problem on a surfboard blank ready to be shaped. I believe what Swied is referring to however, is the "bow" along the length of the board which affects his jointing it flat with minimal waste on the jointer.
I finally found something that answers the original question that I posed in this thread. I was in Target the other day and saw a laser leveler for $14. Check it out up on the shelf below.
Here you can see the line projected all the way across the board. This came in handy when I cut out the profile of the board. The central glue line was not straight. I centered the line so that the glue line crossed the true center line at the nose and the tail. No one will ever know. The curve is too subtle for the eye to see, but the laser caught it.
My laser level was really cheap at the Oceanside swap meet, 2 bucks, but mine has a different name, chalk line, it stays on the board after the batteries die and I am the only shaper among 5 in our shop that owns one, donkey’s
Heh- agreed. Similar situation: buddy of mine was out on a smallish boat in the fog and it was getting dark. He figured 'Oh, no problem, I have a GPS on board' - except the batteries were dead. Follow that with 4 hours of slow navigation in Braille.
So, we're putting a plain old magnetic compass on the thing.
But, while we're on chalk lines.... my problems with 'em have always been the width of them and how the chalk sometimes blows off just ahead of a circular saw blade. Given a choice, I like a knife cut scribe mark to cut to or the line from a freshly sharpened pencil, but has anybody tried the fine line chalk boxes, say like these? http://www.tajimatool.com/products/inkchalk/chalk_rite/view.php?page=all
thanks
doc...
Doc, as a kid on the Cape in the 50’s, our summer next door neighbor, Joeseph Anastasia, a Boston Hyde park resident and owner of a “trash” business, had a nice lttle inboard pleasure/fishing boat.
My dad and he became real good pals and would spend summer days fishing Cape Cod Bay and as far as off Provincetown, my father an Airforce pilot at Otis, took along his circular slide rule to keep track of fuel consumption and engine RPMS, boats were just like planes, you can only go so far on X gallons of gas at x RPMS.
One weekend Joe goes fishing with out my Dad, it is a little hazy on the Bay and after about any hour and a half of trolling, pulls along side a fishing trawler and asks how far offshore are “we”, the captain of the trawler tells him he is on course for Ireland, completely missed Provincetown
My laser level was really cheap at the Oceanside swap meet, 2 bucks,
but mine has a different name, chalk line, it stays on the board after
the batteries die and I am the only shaper among 5 in our shop that
owns one, donkey’s
I have to agree with the Genius. I use a chalk line for many things. I also check stringer glue ups.
Doc mention the chalk blowing away from the circular saw. I use Clear Acrylic on my chalk lines to maintain my layout. When doing Framing, Marble, Granite, Tile even Shaping the Chalk line is very simple and extremely use full.
Don’t get me wrong the Lazers available today are great tools for different appications. i own 2 of them however for this application the chalk line is the call.
Surfding
Haaa- funny you should mention that.
You see, my first real job out of high school was on a boat delivery job, bringing a lobster boat back from Maine to the Cape.
And... well, the Maine lobstermen have kind of a mixed reputation. Some of 'em tend to be really local, finding their way along from buoy to buoy or rock to rock. And this boat was...different. The fuel tank held maybe 150 gallons, but the thing was the gas up there wasn't too great, so the bottom hundred gallons was kind of for water and sludge to settle into. You could only really use the top 50 or so, which was maybe 10 hours worth.
And the navigation, that was by guess and by god. Boat had this J.C. Whitney car compass, mounted next to the throttles which in turn were nice and chromey but I suspect there was a good deal of iron in 'em. Might have been chrome plated iron for all I know.
And we bumbled along down the coast, heading for the Cape. Eventually we found the Cape Cod Bay end of the Cape Cod Canal and kinda hung in there until the sun came up, one of those hazy mornings in June just like you're thinking of. Headed a little south of east, we were aimed for Rock Harbor, and we should have hit it smack on. Well, if the compass was anything near accurate, that is.
Nope. It was off by something like 80 degrees.
Instead, once the haze burned off, there was ( well to the west ) a big tanker steaming along towards Boston. Uh ohhhhh....and also thinking that we might not have had much gas left that we could get at. The skipper was a 70 year old retired scallop boat commercial fisherman, he pulled a course out of his hat and we made it into Provincetown Harbor, but not by much. Then, we made it to Rock Harbor after adding a good deal of fuel. It was clear and we could do it all by eye.
So, I think once the compass is in this boat, I'm going to swing it, get an idea of just what the thing is really pointing at when the compass says it's 'North' and so on. And write that down on a card glued right by the compass.
And then there's the guys who drifted almost to Newfoundland when their outboard went dead off Chatham. The guy who wound up getting the motor going again and got them in is an old motorcycle and surfing buddy of mine, now he's a big deal in the Alaskan fisheries. And, come to think of it, he worked for G&S for a while too.
http://people.seas.harvard.edu/~leslie/Charts/13246_1.gif - a Cape Cod Bay chart, for anybody who's wondering what Jim and I are talking about. and a few more charts here: http://people.seas.harvard.edu/~leslie/Charts/charts.html
doc...