dodgeram99 Posted May 12, 2015 Report Share Posted May 12, 2015 I glued up 3 peaces of cherry to make a panel. After glue up, the panel decided to bow a little bit. Its not much, about 3/16 on an inch. If I push done on the bowed corners the panel is flat. I cant joint it because the panel is 16x20. I was woundering if i spray water on top and put weight on it to push it flat and let in dry. Will this take the bow out? Or will it come back? Quote Link to comment Share on other sites More sharing options...
..Kev Posted May 12, 2015 Report Share Posted May 12, 2015 I have done this with some success and I've also done it with no success. Don't put too much water on it but, keep it moist and clamped flat. I usually keep them that way for at least 24 hours but, longer if I have time. In the end, all you lose in the attempt is time. Quote Link to comment Share on other sites More sharing options...
dwacker Posted May 12, 2015 Report Share Posted May 12, 2015 You need to know why it did what it did. I would first make sure they were jointed right to begin with. If your jointer fence is off even the slightest bit and you did not alternate the faces it is impossible to make a flat panel. Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted May 12, 2015 Report Share Posted May 12, 2015 I wouldn't clamp it down to a solid surface. I usually will suspend a piece bow up on pyramids and place my heavy routerus on top. Like pb said, you should first check your jointer fence. If your sure its dead at 90* then give it a chance to rest back. Any idea what caused the bow? Did you lay it flat on something after milling? Is the wood not dry enough? Quote Link to comment Share on other sites More sharing options...
dwacker Posted May 12, 2015 Report Share Posted May 12, 2015 Don't even bother to check your jointer, even if you managed to get the fence perfect the knives will be off. Always assume that your jointer is off. Besides having one less machine to fuss with your panels joint will alway be correctly joined if you alternate the face. Don't look at cupping as a whole when doing a panel. Check each board as individuals with a short straight edge and look for raised glue lines between the boards. It only take one board to warp an entire panel. Quote Link to comment Share on other sites More sharing options...
TerryMcK Posted May 12, 2015 Report Share Posted May 12, 2015 Is it bowed along its length, cupped across it's width or potato chipped? Quote Link to comment Share on other sites More sharing options...
dodgeram99 Posted May 12, 2015 Author Report Share Posted May 12, 2015 When I went to glue them up I didnt alternate the boards. the U saped grane on one board is up and the other 2 are down. The 2 that are down are side by side. Ill give it a shot. Like TIODS say. Ill just lose some time. Quote Link to comment Share on other sites More sharing options...
TerryMcK Posted May 12, 2015 Report Share Posted May 12, 2015 If you have enough width to play with you can always rip it again and reglue with alternating boards. Sounds like it's cupping. 1 Quote Link to comment Share on other sites More sharing options...
dwacker Posted May 12, 2015 Report Share Posted May 12, 2015 When I went to glue them up I didnt alternate the boards. the U saped grane on one board is up and the other 2 are down. The 2 that are down are side by side. Ill give it a shot. Like TIODS say. Ill just lose some time. Alternating has nothing to do with grain direction. It's how the boards are jointed. 1 Quote Link to comment Share on other sites More sharing options...
AceHoleInOne Posted May 12, 2015 Report Share Posted May 12, 2015 What is the "panel" going to be? Table top or something else? -Ace- Quote Link to comment Share on other sites More sharing options...
dodgeram99 Posted May 14, 2015 Author Report Share Posted May 14, 2015 After trying the water/ clamp idea. it didnt work. I riped the bords apart rejoined and reglued up. I also placed the bordes in the right order, and the bow is gone. thanks guys for all the great advice. 1 Quote Link to comment Share on other sites More sharing options...
..Kev Posted May 14, 2015 Report Share Posted May 14, 2015 After trying the water/ clamp idea. it didnt work. I riped the bords apart rejoined and reglued up. I also placed the bordes in the right order, and the bow is gone. thanks guys for all the great advice. Glad it worked out for you! Quote Link to comment Share on other sites More sharing options...
ponderingturtle Posted May 14, 2015 Report Share Posted May 14, 2015 Alternating has nothing to do with grain direction. It's how the boards are jointed.image.jpg Exactly. It is like when Shannon talks about using a plane and jointing both edges at once, so that it doesn't matter if they are perfectly square as long as they are complimentary angles Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted May 14, 2015 Report Share Posted May 14, 2015 Alternating has nothing to do with grain direction. It's how the boards are jointed. image.jpg Wouldn't this cause issues later with the grain running two directions? I've made the mistake (of reversing the grain on a few pieces accidentally ) on cutting board blanks and it's a nightmare to flatten after glue up. Quote Link to comment Share on other sites More sharing options...
dwacker Posted May 14, 2015 Report Share Posted May 14, 2015 Wouldn't this cause issues later with the grain running two directions? I've made the mistake (of reversing the grain on a few pieces accidentally ) on cutting board blanks and it's a nightmare to flatten after glue up. Has nothing to do with grain. How you set up your panel lay out is entirely up to you. When you joint the boards one bottom goes against the jointer fence then one top then one bottom then one top and so on. My guess is most of the time when folks get a cupped panel after removing from clamps its not a cupped panel at all. 2 90 degree angles obviously nets a flat glue up. On the other hand two 89.75 degree angles nets what would resemble a cupped panel the more boards you have in the glue up the worse it will be. Quote Link to comment Share on other sites More sharing options...
Guest Posted May 14, 2015 Report Share Posted May 14, 2015 Wouldn't this cause issues later with the grain running two directions? I've made the mistake (of reversing the grain on a few pieces accidentally ) on cutting board blanks and it's a nightmare to flatten after glue up. If you are flattening with hand planes, the changing grain direction will be a challenge. You might get some tearout. If you are flattening by sanding you will be fine. But the grain direction will not cause cupping. Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted May 14, 2015 Report Share Posted May 14, 2015 Has nothing to do with grain. How you set up your panel lay out is entirely up to you. When you joint the boards one bottom goes against the jointer fence then one top then one bottom then one top and so on. My guess is most of the time when folks get a cupped panel after removing from clamps its not a cupped panel at all. 2 90 degree angles obviously nets a flat glue up. On the other hand two 89.75 degree angles nets what would resemble a cupped panel the more boards you have in the glue up the worse it will be.with panels, I can see your point. With something like a bench top, that the edge grain will be up is what my brain was thinking about. Quote Link to comment Share on other sites More sharing options...
dwacker Posted May 14, 2015 Report Share Posted May 14, 2015 with panels, I can see your point. With something like a bench top, that the edge grain will be up is what my brain was thinking about. Grain direction doesn't change. Only thing that changes is what face goes against the jointer fence. For example your making a work bench with 3"x 3" x 48" boards glued together. Your layout is predetermined by you prior to jointing. All the glue joints should get alternating jointed edges done on the jointer. The top and bottom would then get the planed edges. Don't mix and match planed and jointed edges. Quote Link to comment Share on other sites More sharing options...
..Kev Posted May 14, 2015 Report Share Posted May 14, 2015 PB is correct. If you flip the face against your jointer fence each time then the edges will match up perfectly and the panel will be flat. Doesn't matter if it's a panel or a thicker table top. Doing this takes any imperfection that may me in your jointer set up and mirrors it on the adjacent board. Quote Link to comment Share on other sites More sharing options...
Guest Posted May 14, 2015 Report Share Posted May 14, 2015 You guys are talking about two different problems. The cupping is because his edges weren't a perfect 90. PB's solution corrects for that and should be SOP. If you are hand planing a panel after glue and your face grain has changing directions you can get some tear out. But if you glued your panels correctly you should only need a light sanding. Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted May 14, 2015 Report Share Posted May 14, 2015 You guys are talking about two different problems. The cupping is because his edges weren't a perfect 90. PB's solution corrects for that and should be SOP. If you are hand planing a panel after glue and your face grain has changing directions you can get some tear out. But if you glued your panels correctly you should only need a light sanding.Correct, I wasn't explaning myself well but just let it go because it's not dramatically important. Quote Link to comment Share on other sites More sharing options...
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