Before the hardwood face veneer lamination ,should check if the face veneer has overlaps or shrinkage ,then pick them outside .
Or spray uniform water on the surface to make the face veneer flat
By spraying water on the face of the veneer ,When doing the water spraying ,as the good firbe will obsorb the water ,if just spray only one or two edges of the face veneer,the face veneer would be not flat ,two ends or one end may be would wider than the center /middle of the face veneer,when laminating the face veneer would be a big quality issues ..High humidity will cause poorly bonded wood to expand,Remember water will act to expand wood.
If only spray the water on the surface of the middle/center of the face veneer,then the middle area should be more wider than the two ends ,also have big quality issues .
So ,when spraying the water ,should be uniform to the whole piece of the face veneer …not just one location …
If the whole face veneer are flat ,then no need to spray any water on it .When don’t use the faace veneer ,make sure pack them by some plastic bags and seal them ,don’t let the water go .Spraying water over the face surface just before gluing is good enough for moderately rippled veneer ,Flattening veneer ,most veeers are flat enough to glue straight down ,but those that are severely rippled or bubbled are best flattneded before use,otherwise they may split while dry andunder the pressure of hot pressing,also you will not be able to achieve a good result when assembling matched veneers unless the veneers are flattened .Spraying water over the face surface just before gluing is good enough for moderately rippled veneer ,it immediately becomes flxible enought to hot prsess . For pronounced ripping,use the technique described below ,flatten veneer that has warped by dampening it with a light misting of water ,wipe away any excess water.Place the dampened veneer between two boards,you can flatten severals sheets at a time ,but you must put a sheet of absorbent paper betweend each sheet ,Check after a few days if the vener is still not flat ,repat the process and leave for a few more days.
If the face veneer are bingtangor or okoume taht is ok no need to spray water ,as the texture or wood grain is much different from birch or maple …