I am just getting into edge gluing to make wide boards, say around 18 inches. Each time that I try the finished board seems to warp across the board. I am positive that the board was flat in the clamp and stayed there for a few days.
Should I use several narrow boards or a couple of wider boards? Is the end grain at the end of the boards important?
Thanks for your help.
You can find lots of information on this by looking for things like "edge gluing" in a search engine.
There are lots of others out there with more experience than me, but one way to minimize this is to use narrow boards and arrange them so that the curve of the end grain alternates up and down. If the boards warp, you'll get a slightly wavy top rather than a totally cupped one.
Chris
Start with properly dry materials. Got a jointer? Planer? (or their cordless equivalent?) Rough your stock out to just over it's final dimensions, and allow your stock to acclimate to it's final environment for a couple of weeks. Make sure that air can flow around all sides while you're waiting for this to happen. Then do a final dimensioning, removing material as evenly as possible from all sides. After glue-up, again allow the panel to rest where the air can freely get to all sides, not lying flat on a benchtop, for example. Sealing/finishing all sides and edges will help your efforts, too. Tom
What is important is the proper selection of your material, all the way from the type, to how it was originally cut from the log, to the moisture content when you use it.
And there is probably no better way to get a handle on that than:
Also consider that your jointer is never at a perfect 90 degrees. The way to correct for this is to alternate the cuts. Rather than edge join all of the boards with the down side against the fence, alternate; down side against, down side away. Also if you use a lot of pressure on your clamps, they will bow a bit. This is why you alternate clamps, one up, one down. robo hippy
set the fence properly. :)
Several responses, some good advice. Above all, have your wood acclimated. Could be a couple of weeks, could be more, depending on the source and storage of the wood. Construction grade with high turnover may have to shed
10% to get in line with indoor conditions, because it leaves the mill at ~20% moisture content. That's a couple months. Second, get edges at 90 degrees before you draw the clamps. Don't have to be anal about it, you can set the jointer fence at a clean angle, or you can do the flippity flip. I figure that fence is better at holding 90 than I am, so I take what it gives.Then there's the "smiles" controversy. I think its a pretense. I get the boards arrayed to look the best and glue 'em. Years in dad's shop, my shop, school shop seem to show that it really doesn't make much difference as long as you don't try to join the first board away from the heart to others of its ring curvature.
What can make a huge difference is the way you use the clamps. You want center of the screw aligned with center of the board with pipe or bar types, and there are few who take the time. Can screw things up real fast if you don't draw straight through the center, but toward an edge. I use some of my handy shims to elevate the glueup and make it so. The Besseys are a good thing to have, but I still alternate. Lay a board across the glueup to check for flat, even if you're not using cauls.
When you say finished... do you mean assembled or poly/shellac/varnish/lacquer?
Did you "fininsh" one side of the board? You need to finish all sides of board. or you can expect serious cupping.
Why not just fix the tool?
My DJ-20 rarely finds 90 degrees all by itself. Three seconds with the
6" combo square in my pocket and a twist on one lever makes it all perfect. It's so easy that I no longer bother to fine tune the 90 degree stop.The same can be said for all blades and miter gauges. 10 seconds of checking can save a bunch of rework and wasted material.
Barry
damn... nobody mentioned an over weight Shakespeare??
mac
Please remove splinters before emailing
Agreed ... but I still alternate cuts on the jointer when preparing stock for panel glue-ups. It is a simple, effective way to put a proven geometrical principle to work in my favor.
... and I generally need all the help I can get.
The one thing I don't like about it is that (on average) it means jointing half of the boards against the grain...
I do it with hand planes (pairings), but never had the reason with decent power tools.
No, when I saw the thread title my first thought was Burl Ives...
C'mon, Duane ... that's really stretching it as a reason. We're talking edge jointing boards for panel glue-up, not face jointing.
In my experience edge jointing boards for panel glue-ups that would rank somewhere down there with the least of my worries.
'Pends on the stock....I've been doing a lot of maple recently and it is really nasty about tearout...then one has the little flecky spots on the edges that don't _quite_ mesh. W/ something like oak or walnut, one would undoubtedly never notice.
"Chris Friesen" wrote
Sadly, you'll also get a board composed of strips whose grain runs in alternate directions.
Can't win can you?
Jeff G
Or the tearout happens on the corner, which will show on the face.
Barry
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