Replies to This Discussion

Permalink Reply by Jim burt on May 21, 2012 at 1:47pm

What are you  making?....

Permalink Reply by James Avery Cunliffe on May 21, 2012 at 2:17pm

Just following the free instructions for a cbg - The local lumberyard has a great selection, but only in 4ft length.

Permalink Reply by wormil on May 21, 2012 at 2:35pm

The wood is warping after you laminate? Two things cause warp, moisture loss/gain; or internal tensions relieved during resawing. You should probably wait a week after bringing the wood home to allow it to acclimate. Also learn to read the end grain, flatsawn is more prone to warp than quartersawn.

Maybe you could walk through the steps from rough lumber to taking the clamps off. And a few pictures wouldn't hurt.

Permalink Reply by Kevin Lawton on May 22, 2012 at 12:38am

All wood 'moves around' somewhat in response to moisture/temperature/humidity - it is in the nature of wood to do so - but different woods to this to different extents.  Maple moves less than many other woods, while Oak and Poplar move quite a lot.

There are several things you can do, combined, to help lessen the problem.

First off, wood which has been 'quarter sawn' at the sawmill will retain its shape far better than that which has been 'flat sawn'  due to the fact that the wood cells towards the outside of the tree trunk are fatter than those towards the middle, and so expend/contract more.  Ideally, if you can, cut your own timber.  Otherwise look carefully at what you are buying from the wood yard - examine the end grain.

Secondly, choose timbers which are appropriate for their purpose. There are several reasons why Oak isn't  one of the best woods for use in making musical instruments, while Maple, Mahogany, Rosewood, Ash, Yew, etc are.

Thirdly, make sure the timber you use has been thoroughly seasoned  This doesn't just mean 'drying out' but also involves allowing the wood to age somewhat so it gain strength and hardness. I tend to mostly use either second-hand timber (old furniture parts) or fell and season my own. 10 to 20 years in my loft seems to suit most local hardwoods. Table legs and axe handles are good sources of used timber for making instrument necks.

When laminating, it can be very helpfull to 'balance' the laminations - for example, a core of one type of wood surrounded by layers of another wood on either side.  This has to be done when veneering large panels to avoid the veneers pulling the panel into a curve.  Pay attention to the direction of the grain in each lamination too.

Hope this helps.

 

Permalink Reply by James Avery Cunliffe on May 22, 2012 at 3:21am

Fantastic information - Thank you all. 

Permalink Reply by James Avery Cunliffe on June 12, 2012 at 5:15am

Success! Quarter sawn, matched grain to cancel the stresses out, 2 poplar sandwiched maple and I also changed glue to a better quality one. I let the wood "dry" out for a week as well even though I live in a high desert - it all did the trick. All the other suggestions were terrific, but I am working with a handful of clamps, a file and saw (mostly sitting on an old tire). No table, no electric tools and a limited budget so some of the other ideas not so possible. Thank you everyone again.