lamination thickness?

[TreyNC]

I recently posted a question about lamination woods, and  got some much needed information. So now my question is how thick should a lamination be for a back? I ended up with a 1/8" thick piece of red oak then planed it down to 1/16" and used it as a lamination on the back, but when I took the camps off the bow the oak had warped. It was cupped in several places lifting up almost 1/8". Was this the oak?

[DanaM]

Don't know much about laminated bows but I don't think oak is generally used as a backing

[snedeker]

Badger uses it with good effect.  When you clamped it down, you need to use a slat of scrap wood or a bunch of short cut off (1.5x3") betwen the core and the clamp to distribute the pressure across the whole surface.  If you used Titebond, you can work in glue in the raised areas along the edges and re'clamp it down a bit at a time to fix the problem. 

I haven't used red oak as backing, but plan to try it on some middle weight wood, maybe black locust or maple.  1/16 might be a tad on the thin side but it ought to work.

Dave

[Justin Snyder]

Often when using water based glues like TB with a wood backing you will have an issue with the backing curling.  That is just what wood does when it gets wet.  I use wood blocks with rubber bands as clamps when I am doing something like that.  I know there is a picture around here somewhere I will see if I can find it.  The other alternative (that most guys don't want to hear) is to use hide glue.  Hide glue holds as soon as it cools, then as it dries it pulls the joint even tighter.  This is the ideal application for hide glue.  Justin
Here is the thread showing the rubber band and wood block clamping meathod I use.  http://www.primitivearcher.com/smf/index.php/topic,1978.0.html

[adb]

I use 1/8" hickory, and 3/16" maple as backing woods. You need to clamp (or wrap) your backing to the belly with either another piece of wood, or a form. If you just try and clamp the backing, it will warp. You need to sandwich the thin backing strip between thicker material, so it comes out flat. Check out my Holmegaard Build Along from about a month ago, and you can see how I do it.