Wood storage, milling, where did I go wrong?

[Arguseyed]

Last weekend I was building a simple panel cutting sled and grabbed a piece of 5" wide 4/4 scrap poplar to use as a fence. Yeah, I know poplar is not the best choice but it's what I had. I proceeded to face joint, plan to thickness, edge joint and then rip to size. Final dimensions = 31" long, 1.5" wide, 3/4" thick. When finished, laid it across the table saw and it was perfeclty flat on all 4 sides.

Did all the milling Saturday and came out Sunday morning and looked at it and you'd thought I was trying to make a pretzel, severe twist. The scrap has been in my garop (garage-shop) for about 3 months so it should have had plenty of time to acclimate. Is this just one of those things that can happen sometimes or is there a part I'm missing?

Thanks guys,

Jeremy

 

[JimmyC]

You got me, I would've done the same thing. Maybe some one else will know what happened, I'm interested in the answer.

Jimmy

 

[DaveO]

Did you leave it sitting on the table saw over night? If so that would have blocked moisture transfer from one side of the board. When you mill a board you remove wood and often expose the center which might not be as dry as the outer surfaces. Ideally you should either mill a board and then allow it rest again with good air flow all around it, or start to work with it right away so it is restrained in the piece that you are making.
Dave

 

[jeff...]

Couple of things I've learned THE HARD WAY.

* Don't leave any wood sitting on a flat steel plate of any length of time, doing so impedes the airflow. Believe it or not dry lumber is like a sponge... it's sucks up moisture caused by condensation quicker than anything around especially when it can not breath on one side.

* If you have a concrete floor in your shop... store your dressed ((milled)) lumber by laying down a piece of cull lumber on the floor (plywood will do), stand your dressed lumber up on the cull and let them lean up against the wall. Your dressed lumber should stay put then. That is as long as you don't leave it there for long periods of time.

* Right on Dave - fit your dressed lumber as quickly as possible into you project.

* Use quarter sawn lumber when possible - it's much more stable than flat sawn and less likely to "move" cup, twist, bow, etc...

 

[Keye]

Jeff nailed it. Leaving milled wood on the TS is the worst place in the world to leave. I think the difference in temp and of course air flow is what causes the overnight drastic change. The other thing is the humidity level has changed drastically in the last few days. I have some unfinished drawers that fit great several days ago, before the stomach flu hit me, now they will not even go in the openings. Wish I had a chance to seal them before the humidity went up. Also glad they were not in the dresser.:eusa_clap:eusa_clap

 

[Travis Porter]

I remember reading in one of my books awhile back, you go through, mill your lumber get it nice and flat, joint it, plane it, rip it true, and then come back the next day and it warps. It isn't uncommon, and it does happen. Minimizing it is the key and the suggestions provided are good ones.

 

[GarageWoodworks]

Did you plane all of the material to final thickness from one face? If so, this will definitely lead to a warped board (DAMHIKT).

After face jointing one face, plane opposite face and then alternate faces in the planer as you close in on your final thickness. This becomes a bigger problem as the board gets longer.

 

[mkepke]

Wood will seek to equalise the forces acting on it. In the rough, after months in your shop, it should be stable (aclimated). Mill it, and you change the forces acting on it, so it moves in order to re-equalize.

Techniques like allowing even airflow, planing both sides equally, etc. are good - are intended to minimize the chances of 'disequilibrium'.

Letting the lumber 'rest' between millings is another approach..mill a little, the wood equalizes (moves) in response. Mill some more, the wood equalizes (again) in response, etc. In this way, you converge to the finished dimensions and the lumber's equilibrium state at those finished dimensions.

Using dressed stock immediately is yet another approach. You mechanically restrain the stock *before* it equalizes. Then it still equalizes, but it equalizes in response to the force of the mechanical restraints.

Net-net, in all cases, the wood is reaching equilibrium with the forces acting on it.

So, if you understand that the wood must reach equilibrium, you can think how to help the lumber reach equilibrium in a way that's most beneficial to you.

-Mark

 

[Arguseyed]

Thanks all for the suggestions and tips! I'll be sure to employ them next time around. Gotta love this site! Where "wood" I be without it.......

 

[ToeNailer]

Some very nice replys!

And wow has the humidity changed......actually brought a few pieces in the house today........

Mill....rest ...mill use!

Jim