On Tuesday, May 9, 2017 at 5:35:47 PM UTC-5, DerbyDad03 wrote:
On Tuesday, May 9, 2017 at 5:16:17 PM UTC-4, Andy wrote:
On Sunday, May 7, 2017 at 7:34:42 PM UTC-5, Frank wrote:
On 5/7/2017 7:46 PM, wrote:
On Sun, 7 May 2017 16:09:07 -0700 (PDT), Andy
wrote:

I have a 2 x 4' piece of underlayment lumber.

Any way to flatten it ?

Thanks,
Andy
Nail it down.

The real answer is probably put it in a container large enough to pump
steam around it for a couple of hours, take it out and bend the hot
board and clamp to let it dry and set. Seen it done for making
furniture but who in their right mind does it for a 2X4? Easier to buy
a straight piece.

You must not buy much lumber.

Straight flat pieces are the exception.

Andy

That would depend on where you buy your lumber.

Allow me to quote from an article I ran across just last night:

"Beginners often start by perusing the limited options available at
home centers but are eventually drawn to the greater variety and quality
available at lumberyards and specialty hardwood stores."

Then there's mail order, Craigslist, reclaimed wood dealers, etc.

If you are serious about woodworking, don't limit yourself by shopping
where the crap is sold. I've built projects from red oak that I've bought
on-line, reclaimed Douglas Fir that I found on Craigslist, etc. All
perfectly straight.

I still have a bunch of the reclaimed Doug fir that was used to build
this bed. Not a warped or twisted board in the lot. Some pieces were over
16' long and perfectly flat.

http://i.imgur.com/80jaux9.jpg
http://i.imgur.com/GTDm9VG.jpg

Most wood is air dried instead of kiln dried.

Kiln dried wood has around 6% moisture as opposed to 15% moisture for air dried wood.

Higher moisture content = more warpage.

Andy