Wood's Awesome Posted August 14, 2012 Report Share Posted August 14, 2012 I am new to woodworking, and I am curious about wood movement. I haven't found a topic in the forum dedicated to wood movement (although it is entirley possible I missed it), so I thought I'd start one so myself and others can learn about it. I'm curious if all kinds of wood, from the basic common woods to exotic woods, warp, expand, and contract with weather changes and what other factors cause wood movement?? Also, when does the movement of wood affect how one joins together a wood project?? My small experience: I bought some pine wood, stored it in my garage for a few days, and when I came out to use it I sadly found that it had warped, so the 30 minutes I stood there trying to find the truest pieces was futile But when I bought some Poplar and stored it for a week, I noticed it didn't warp much at all Any advice and shared experiences (I love reading other woodworker's experiences) on this topic would be much appriciated. Wood's Awesome!! Quote Link to comment Share on other sites More sharing options...
Trip Posted August 14, 2012 Report Share Posted August 14, 2012 Hoadley, Understanding Wood http://www.amazon.com/Understanding-Wood-Craftsmans-Guide-Technology/dp/1561583588 Quote Link to comment Share on other sites More sharing options...
Onboard Posted August 14, 2012 Report Share Posted August 14, 2012 The Woodshop Widget – The 3rd icon from the left is for calculating wood movement. The 2nd icon from the right allows comparison of 2 different woods including shrinkage. The 3rd icon from the right shows shrinkage of a particular wood. Kenneth Woodruff created this applet, and has just come out with an Android version. It’s on the same page as the widget link. Quote Link to comment Share on other sites More sharing options...
Wood's Awesome Posted August 14, 2012 Author Report Share Posted August 14, 2012 hhh, thanks for the link to Hoardly's book. I'll probably end up adding that to my book collection. It looks like it has a lot of information for someone like me according to the description/reviews. On Board, I like that application. I carry a smartphone with me 24/7, but never thought about checking Google Play, thank you! Thanks again for the info Wood's Awesome!! Quote Link to comment Share on other sites More sharing options...
MTC Posted August 15, 2012 Report Share Posted August 15, 2012 All wood no matter the species will work against you - it will warp, swist, expand and contract. The factors effecting it are numerous, including how, where and when it is stored how it was cut (flat, Rift or Quarter sawn). Are you stickingthe wood and allowing air to circulate? (never lay on a concrete floor). There are so many variables. I always stick new wood (and place a couple of 80lbs bags of sand on top to keep it flat) and leave it to aclimate for at least 2 weeks - then dimension the wood over size and again leave to aclimate for a few days before final dimentioning and at that point put it together! that way there is less likelyhood of additional movement. The book by R. Bruce Hoadley is an excellent choice. Good Luck! Quote Link to comment Share on other sites More sharing options...
Howtoworkwood Posted August 18, 2012 Report Share Posted August 18, 2012 All woods movement is to do with the relationship between water and wood. There are two types of water in wood. Free water and bound water. Free water is water that is in the cell cavities and when it is lost or added to the wood then there is NO dimensional change. Bound water is water found in the cell walls and when that is lost or added then dimensional change DOES occur. All types of wood are affected by this phenomenon although some may suffer more or less dimensional change than others. Why doesn't the wood shrink uniformly!? Because wood is an anisotropic material this means it does not have a uniform composition so therefore different area shrink at different rates. This is what leads to the warping you found. Although some of the difference will be to do with the species much of it will have had to do with the moisture content you bought the wood at and the relative humidity of the air in your garage. Also the method of stacking and timber dimensions. Sorry it's such a long answer and there's more I could say but hopefully that has helped you understand a bit. As previously recommended R Bruce Hoadley Understading Wood is a fantastic guide for us wood workers even if it is a little wordy at times. Quote Link to comment Share on other sites More sharing options...
Trip Posted August 18, 2012 Report Share Posted August 18, 2012 ==>thanks for the link to Hoardly's book. I'll probably end up adding that to my book collection. If you keep at this diversion/hobby/passion/etc for long enough, you'll work-it-out for yourself. Hoadley is a shortcut -- you get everything you never wanted to know about wood in one place.... Quote Link to comment Share on other sites More sharing options...
TerryMcK Posted August 18, 2012 Report Share Posted August 18, 2012 One experience I have here. I had a nice flat, rough sawn board of mahogany that had been in the shop for quite a while. I planed to thickness, jointed it and glued it together all in one session to make a 2 board top for a cabinet I was making. It's about 32" x 18" and 7/8" thick. It was 5/4 stock if my memory serves me so had quite a bit of milling to thickness exposing quite a lot of internal fibres, The next day when I took the clamps off it was flat as a pancake. I left it over the next few days as I knew i would cup. First it went up at the long edges by quite a lot (5/8" relative to the centre!). I'm sure fellow wood workers have all seen this amount of cupping. I flipped it over and left it a few days. It then curled up the other way. I repeated this for quite a few days and gradually the exposed fibers came to the same humidity as the shop. I was then able to finish it off, cutting it to size, tapering the edges, scraping the top and applying a little edge routing. The top was really flat by then. Fortunately it didn't bow or twist end to end so I only had cup to cope with. I applied some water based finish over a few days and waited until it had finished moving again due to the absorption of moisture in the finish and it came out perfect. I was careful to apply finish to both sides in the same session to balance out the moisture absorption. One side will always dry quicker than the other, due to more surface area being exposed as ventilation on the underside is not always as good, so a small amount of cupping is inevitable. When I took it indoors to the cabinet it moved again whilst it acclimatized to the humidity in the house. The point of this was I was prepared to wait for the wood to stabilize to the humidity of the shop after doing all the milling, jointing etc in one session. I was also aware that it would move (lots) during this process despite the amount of time the board had been in the shop. I was rewarded with a fine, flat top to grace the cabinet. Quote Link to comment Share on other sites More sharing options...
Grainy Posted August 23, 2012 Report Share Posted August 23, 2012 The Woodshop Widget – The 3rd icon from the left is for calculating wood movement. The 2nd icon from the right allows comparison of 2 different woods including shrinkage. The 3rd icon from the right shows shrinkage of a particular wood. Kenneth Woodruff created this applet, and has just come out with an Android version. It’s on the same page as the widget link. Just installed the iPhone version. Nice! But I'm in Canada so it is forcing me to use metric, but inches is most common here and I cannot find a setting to switch units in the iOS version. This is going to help me deal with wood movement. Quote Link to comment Share on other sites More sharing options...
Onboard Posted August 23, 2012 Report Share Posted August 23, 2012 Grainy, the online version shows a “Preferences” link to allow you to switch between Imperial and Metric scale, as well as 3 different currencies. On the webpage advertisement for the iPhone version, I do see a “More” button in the lower right corner of the screen. Maybe it’s there. If not, then hopefully someone who uses the iPhone version can post an answer as to where the preferences are located. Quote Link to comment Share on other sites More sharing options...
EricFortin Posted August 24, 2012 Report Share Posted August 24, 2012 You can change the unit settings from the general settings app on the iPhone. Quote Link to comment Share on other sites More sharing options...
culturist Posted September 21, 2012 Report Share Posted September 21, 2012 Are you stickingthe wood and allowing air to circulate? (never lay on a concrete floor). Beginner here... I just read this and had to run out to the back of my shop to lift 2 walnut slabs off the concrete floor. Quote Link to comment Share on other sites More sharing options...
TRBaker Posted September 21, 2012 Report Share Posted September 21, 2012 Wood is the worst possible building material you can use, but it's the best we've got. : ) Quote Link to comment Share on other sites More sharing options...
Howtoworkwood Posted September 22, 2012 Report Share Posted September 22, 2012 Hey Culturist, If you want to know a little more about how to stack wood to help to prevent moisture movement then read this article I wrote... Click here I hope it helps and good luck with the project Quote Link to comment Share on other sites More sharing options...
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