Hi all
Novice here trying to get some advice to prevent warping or cupping after glue up. I am gluing up some 6-7 inch in width boards x 3/4 for table tops. I have read a few helpful hints on here on here which I have applied like alternating growth rings and clamps I have even tried clamping battens on both sides on the ends while gluing up but when I remove all the clamps leave it for a while and its like a banana. Should I glue up narrower pieces of stock. Please help if there are other options I can try it is very much appreciated
Thanks in advance
Replies
Among other possible causes for your problem, if you used a jointer, be sure the fence on the jointer is at right angles to the bed. Otherwise you will end up making barrels.
>>leave it for a while and its like a banana.
Where and how do you leave it? A panel should never be left laying flat on a flat surface. Air must be able to get easily to both sides. Either sticker it or sit is straight up and down on edge.
Was the wood properly acclimated to your shop before you worked with it?
Did you take equal amounts of material off both sides if you power planed it?
Finally, as has been mentioned, if you jointed the edges are you sure your jointer fence is absolutely perpendicular to the jointer table?
Take all the advice that has been given. It's good. But remember this fact - all panels will need some flattening after glue-up. I have glued up quite a few panels over the years and have NEVER seen one that did not need some work after the glue dries (I own commercial glue racks, too). Admittedly, your problem is much more severe and you need to take remedial action to get them a lot flatter then you have been.
After you solve the immediate problem, either get a drum sander or learn how to use handplanes to bring your panels into final flatness.
Datapip,
Plane all of your pieces equally on both sides. Let'em sit for a couple of days (or more) stickered in your shop to let the moisture equalize.
Lay out all of your pieces with the figures like you want'em. It's a good idea to alternate grains facing up and down.
Make a mark on the face of every other piece. Mark the other pieces on the backside.
Joint each board with the mark facing the fence.
This will ensure that even if your jointer fence isin't square the error won't be magnified when you clamp.
Put a thin coat of glue on each edge.
Don't clamp too hard either. Just enough to close the gaps and have some squeeze out. Make sure you don't rack the panel when clamping.
Stand the panel up to dry. If it's over 60 degrees in your shop, take it out of the clamps after 3-4 hours.
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