I experienced some difficulty jointing the boards for my last balsa board. This time my boards are even longer, and I don't want to waste as much wood trying to get them straight. I have found that running really long boards over the jointer is a challenge. My first thought was to get a long straight edge, and mark a line on the board. I could then use a hand held power planer to bring the board as close to straight as possible. Finally, I would run the whole thing throught the jointer to make the surface smooth and even. My only problem is that I don't have an 11 foot long straight edge. Is it worth searching are for one, or is there an easier way. How does everyone else get around this issue?
you could maybe use a chalk line
pull tight and snap it
???
I like that idea! Geez... why didn't I think of that. Thanks!!
Well, I deleted 11 of the 12 posts. The trouble is that each time I delete a post you lose one point… and I don’t know how to fix that, I’m sorry… I will ask Mike Paler about that.
Arrrrggggggg...
I have no idea how I just made 12 duplicate posts. I think that must be a record.
Now, Ken will know how much you like his idea…
How wide are the boards? You could just use each proceeding board in the layout as the staight edge if they are remotly close to perfect and then cut or join to the line...this would allow each board to mimick the following one (like scribing) keeping cutting to a minimum... Or maybe I am way off base since I not familiar with laminating balsa. Hope this helps..
I think the right tool for the job is a long bed jointer and rollers for in-feed and out-feed.
Might be able to have it done for you at Dixieline or similar yard if you don’t have access.
I would not try it with a chalk line and hand tools, myself…11 foot balsa is too costly and rare to screw up.
Yup. I’ve done numerous projects that involved straightening very long pieces of wood. Mahogany, poplar, maple, you name it. A good industrial grade jointer and rollers for in feed and out feed is the best way to go. If you have access to a heavy duty thickness planer, then you only need to straighten one edge per board.
1 - Straighten an edge
2 - Rip to parallel on table saw
3 - Plane on edge, grouped together
You can make a sled for the table saw… A board with one good straight edge aganist the saw fence and your balsa clamped on top of it.
if you slightly overlap your boards (on a large, clamped sled or jig) and made your cut once, each side would be a mirror of the other if you make one continuous cut.
so…if you layed down your left-hand piece, layed your right hand piece slightly over the left (shimmed so it’s flat) and then used a right-side guide to make your cuts you would get a) visibly straight cuts (due to the guide) and b) a left side and a right side that will be reflective of one another.
how long is your jointer bed?
can you laser sight a couple of extension rollers? (lots of setup)
I'll chime in on this - you can most definitely do it with a long bed jointer and an infeed and outfeed of some sort. Doesn't have to be rollers, though - you can also use tables with smooth surfaces ( like formica) providing they're at the proper heights. And they're not all that tough to make.
Or.....
Forget about the power planer, forget about the chalkline. Myself, I always remember that chalklines are about a fat sixteenth wide and if they're not snapped just right, they can have a little curve in 'em. And planers can be a bit too aggressive
But if you have an 11' flat surface and a sharp long hand plane, you can get it very straight indeed. Which is why a great long plane like that is called a jointer plane. And how do you find out if it's straight or not? Well, by eye and most importantly by fit.
'By fit' you ask? Uh huh - see, why are you jointing these things anyways? To make 'em fit together right, no? So, plane and check the fit, plane and check the fit, until you get it smack on. Doesn't have to be perfectly straight, just has to be a perfect fit. I once did a cherry ( 2" rough sawn) and mahogany ( 4", rough sawn) open stairway with no fancy power tools. Just that 24" plane for getting things straight. It wasn't even metal, looked ( and looks, I still have it and use it) like this: http://www.oldtoolphotos.com/toolphoto.asp?photo=38
And - a how to video here: http://www.youtube.com/watch?v=-l3bx4GEmZY
Hand tools are cool -
doc....
I am guessing here but I think you have 4 inch x 6 inch by 11 foot timbers. You are makeing a chambered board right ? I will bet you that if you joint balsa that long you will never get straight timbers. Why ? there is to much tension in balsa. When you make one side straight and then plane it to a consistent thickness its going to end up curved. If I were going to chamber a 11foot board I would rip my timbers down the center on a bandsaw to give me 2 pieces about 2 inch by 6 inch. then thickness them to to the same thickness. you will now have 2 curved timbers. then I would glue them back together with the curves touching each other and the end sticking out. But I wouldn't just do one set of timbers at a time I would do all of them only glueing each pair. You would have 6 or 7 pairs in a board.
Here is a drawing of what I am trying to explain.
For me this is a case of been there done that. You should always desighn around construction. It will take 26 , 36 inch bar clamps to do this glue up right. Yes , your finished board will look like it is glued up from 2 inch timbers!!
Wow! This is more complex than I thought. Thanks WO for the informative diagram. I think I understand it. How do you rip your boards with the bandsaw? Do you use a fence? Do you draw a line down the middle, and cut through the line? If so, do you have a long straight edge or do you use a snap string?
I don't think that I will need to go through that effort, though. My boards are pretty light (~8 lbs/cu. foot). I'm not going to chamber the boards. It sounds like the WO method is only necessary if you are going to chamber. If the boards curve a little after the jointing and planing, then I think I could just force everything together with clamps when I glue them together (two pieces at a time of course). Am I wrong in my thinking here? If not, then I would probably need to go to Dixieline and pay the $40 or so to have them professionally jointed and planed.
If I jointed every piece flat both sides, it would take 20 pieces of wood per blank, if the stick is to go into a foam blank, yes. The wood will over power a foam blank every time, but building a balsa blank no, I lay out the wood like wood ogre says, opposite curves, it helps the wood to “even out”, but it is no guarantee the lines will be true nose to tail.
I have in my gluing quiver a 2x4 thick walled box tubing 16 feet long, but this at times gets deflected by the shear will of the wood.
This is when I break out the big guns, I went to homo depot and bought 2 -12 foot 2x12’s, I picked through them fot the best ones, ha.
I layed out the rocker profile at the bottom of the sticks, bandsawed them out and then with the section the came out of the top rocker, took it over to the jointer and trued the straight edge.
With these pieces, I butted them flat against the rocker sticks at 90 degrees, counter sunk long self tappers to hold the two sections together, repeat process with the other set.
Now back to the jointer and flatten the faces of the rocker sticks, this is how I built the 12 foot Evolution guns, Larry Fullers 12’ agave, Al Merricks 12’ old growth redwood gun.
I start out with the center pieces, 2 is best, glue or spot glue, add 2 more, then 2 more until I am done.
After the center is glued well, it becomes stable and the additional pieces are then unable to distort the true center line, for glued wood to bend, the outside piece needs to get longer as the outside of a curve is longer than the inside curve.
If it is being spot glued for a chambered blank, I place the curves of the planks touching at the tips and add a few more glue spots near the center, it is less prone for the blank to pop in the middle as at the ends.
After chambering the blank looses at lot of its rigidity and fights back far less when re-gluing.
Unless the piece of wood has wobbles in it, I run it through my thickness planer and clean both sides, the wood may look flat and square, but isn’t, wood shrinks from the corners and the faces are slightly crowned, beside the width is not consistant, varying wildly.
There are no short cuts in doing a good job
Bill Thrailkill was kind enough to offer to come over to help me. He helped me draw out some templates for the rocker and the profile. He also suggested that I not go too crazy with jointing and planing the boards. Back in the days of wooden boards guys like Velzy didn’t care if their boards fit together perfectly. They just clamped everything up with white glue, and then started shaping. Bill suggested that I do the same. I’ll have to admit I was a bit skeptical. It took me a while to come around to believing that it would work. See the picture below to see how much curve there was in my boards. After Bill left I did some measurements, and discovered that all the boards had constant thicknesses. They were just curved. I think that the boards were originally milled straight and true, but the tension in the wood eventually caused it to bow. As Bill described, you can just clamp the opposing curves together. I did a dry clamping run, and sure enough it worked.
Shown below you can see the rocker template on the bottom, and the profile template above. The unglued boards are behind. 
Here I am ready to start gluing. After dribbling some Titebond III over both sides I used a spreader to make sure that everything was covered with glue. You can really see the “natural rocker” of the boards.
Her is the whole mess all clamped to my solid core door work bench.
Here is a close up look at the joint. It looks pretty good to me.
Note… I had originally planned to draw the rocker outline on the boards, and cut them on the bandsaw before gluing. I decided against this just before gluing. Here is my reasoning…
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The wood is pretty light and soft. I should be able to cut it down fairly quickly with the electric planer.
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I just got a new Clark modified Hitachi planer for Christmas. I’m going to want to get some practice using before I get to the critical parts of the board.
I did a lot of the glueing of blanks at Velzy’s in 57 an 58. They were glued in a press which would hold four at a time. The glue was a two part system with one part on one piece and the other part on the mateing surface, it hardened fairly fast and we could glue a couple of batches a day. Most of the balsa came from Baltec and did not have to be surfaced. In those days Dale was not real fussy about the glue line showing and being glued in the press the blanks came out pretty straight. He did get one load of wood that was really rough so he had to buy a planer and joiner so the would could be surfaced before glueing. Now if I make balsa redwood I surface everything, split each piece and mate them as has been suggested, I do not try to glue the whole blank at once, use good straight 2x4s to clamp against and lots of clamps. Just a little history.
The Hitachi has the problem of overloading on wood and having the belt start to slip, also by sawing a pre profile you are able to see the thickness flow prior to gluing.
At Takayama’s years back he had another person building his blanks, they were all 3-1/4" nose to tail and the glue ups were very uneven, plowing them by hand yielded a finished thickness of about 2-1/2", fortunately they were all wall hangers, your looks pretty darn even