Meatwad Posted June 19, 2020 Report Share Posted June 19, 2020 Well I wasted a good bit of time today. I am building a patio chair and I needed a 32 inch (approximately) single board for a backrest support. The particular board I have has a about a 1/8 inch cup right in the center of it. I was trying to solve this using only my jointer and that did not work. The cup stayed no matter what I did. I'm still a rookie at this so I would appreciate some advice on how to handle this better in the future. What can I do when I get into a situation like this? Quote Link to comment Share on other sites More sharing options...
Tpt life Posted June 19, 2020 Report Share Posted June 19, 2020 I’d evaluate the jointer setup. It is purpose built for dealing with cup. Quote Link to comment Share on other sites More sharing options...
wtnhighlander Posted June 19, 2020 Report Share Posted June 19, 2020 Was the cup smiling, or frowning, as you passed it over the jointer? 1 Quote Link to comment Share on other sites More sharing options...
Meatwad Posted June 19, 2020 Author Report Share Posted June 19, 2020 Tpt Life: Is there a good way for me to test that? wtnhighlander: It was frowning. Quote Link to comment Share on other sites More sharing options...
..Kev Posted June 19, 2020 Report Share Posted June 19, 2020 I'm suspecting that you also have some twist in the board. Set the board on a known flat surface (frowning) and check for wobble. This will tell you which corner(s) may be high or low (twist). The high corner(s) will need to be removed first. This can be done on the jointer by keeping the downward pressure on the high corner(s) all the way through the pass. Once that wobble is gone, you should be able to flatten/plane normally. Quote Link to comment Share on other sites More sharing options...
Meatwad Posted June 19, 2020 Author Report Share Posted June 19, 2020 Ugh, guys I'm sorry, I should've said my board is bowed, not cupped. I'm still a noob. Quote Link to comment Share on other sites More sharing options...
..Kev Posted June 19, 2020 Report Share Posted June 19, 2020 2 minutes ago, Meatwad said: Ugh, guys I'm sorry, I should've said my board is bowed, not cupped. I'm still a noob. Ah.. Ok... That's a bit different.. No worries, I'm sure we can help you through it.. Depending on how much it's warped, it may be savable.. Place the board on your jointer so that the high middle is on the bed (smiling). Keep the pressure on one end and keep making passes until the side sits flat on the jointer bed. From there, you can go to the planer. The bad thing with a "warped" board is that if the board is too warped, by the time you get it flat, it may be too thin to use. If the board has a lot of warp to it, it's best to get a different board. If the board is only "warped" a small amount then, the method above should work just fine. Quote Link to comment Share on other sites More sharing options...
krtwood Posted June 19, 2020 Report Share Posted June 19, 2020 I prefer to do the opposite of the other Kevin and have the two ends down. Where you were likely going wrong is you were putting pressure in the middle, which just flattens out the board before it gets to the cutter and then when you take the pressure off it springs right back without having actually done anything to take out the bow. You have to put pressure only on the ends and if you are doing it right you'll hear it stop cutting in the middle and then start again as you get to the end. 1 Quote Link to comment Share on other sites More sharing options...
Coop Posted June 19, 2020 Report Share Posted June 19, 2020 I would rather have a cupped than bowed board. Rip it and have two separate boards, each with less cup and easier to deal with. But at least bowed is better than twisted (fire wood) and can be dealt with as described above. Yep, due to thickness requirements, it may be best to cut your loss and invest in another board. Quote Link to comment Share on other sites More sharing options...
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