The Forestry Forum

General Forestry => Drying and Processing => Topic started by: old3dogg on April 03, 2015, 07:33:05 AM

Title: Vacuum Drying Thin Veneer.
Post by: old3dogg on April 03, 2015, 07:33:05 AM
A fellow ask me a few days ago if I thought it would be beneficial to vacuum dry thin slices of hardwood veneer. What his company does now is soak 8/4 green hardwoods in a vat with water and steam, remove the lumber, slice it paper thin and then run it, piece by piece through a dryer.
His thoughts were to stack the thin slices together, stack them between the hot water platens and vacuum dry them.
I told him that back in the day I use to stack 1.5x3.25 hardwood flooring blanks 3 deep between the platens and dry them. It worked well and greatly increased the amount of board footage we could load into a vacuum kiln.
My thoughts are that yes, vacuum drying the stacks of thin veneer should work.
Your thoughts?
Title: Re: Vacuum Drying Thin Veneer.
Post by: GeneWengert-WoodDoc on April 03, 2015, 11:53:02 AM
I saw a vacuum veneer dryer on the West Coast.  It worked very well except that the final MC was extremely variable.  If they over-dried the load, or at least over-dried some of the pieces so that there were no wets, then gluing was a problem with he over-dried pieces.  Over-drying is an issue for all veneer, but in a hot air system, we can control the humidity to prevent over-drying.

As we have stated before, Den's approach to vacuum drying is different, so it may work for veneer better than the older systems.
Title: Re: Vacuum Drying Thin Veneer.
Post by: Den Socling on April 03, 2015, 03:15:34 PM
We have kilns in Australia, Malaysia and New Zealand that dry lamella for engineered flooring. They put in stacks of thin wood to make a layer about 50 mm thick. I noticed, though, that you had to be careful with storage of dry lamella. We pulled and unloaded a load in NZ one day and it was dry and perfectly flat. A couple days later it was curled and cupped. I assumed it had picked up MC unevenly in the high humidity.
Title: Re: Vacuum Drying Thin Veneer.
Post by: old3dogg on April 07, 2015, 05:28:59 PM
I did give him your name and number Den. Hope this was okay.
Title: Re: Vacuum Drying Thin Veneer.
Post by: Den Socling on April 07, 2015, 07:12:28 PM
Certainly OK with me. I always follow leads. You can also send people to our website: http://www.vacdry.com/
Thanks  :)