I am having a couple of issues with veneering on some work we are doing. One is a slight ghosting of the veneer tape when we tape our joints together. After we remove the tape, it appears to have slightly sealed the wood so that when you stain it, you can see the pattern of where it used to be. The other problem is some wrinkled veneer that we have to flatten. Is there a simple way to flatten it so that it can be glued to a substrate?
From contributor T:
Stop using surface tape. Use a zigzag string application device applied to the underside. Try relaxer to get rid of the waves. Vacuum press or lam bag will help with quality.
Regarding flattening: I'm aware of two types of flattener. One is a glycerin-based flattener that you can make up yourself - search the Knowledge Base here at WOODWEB for the formula. The other is GF-20, which I believe is PEG-based (not certain). I get it from Veneer Systems, Inc. I like it better.
Tape Ghosting - The usual suspects:
Is this happening on species that are subject to tone changes with UV exposure?
Could it be that you have hard water and are seeing mineral deposits? Try distilled water.
Has the face maker changed and maybe a new guy is using more water than previously? Excessive water on the tape can cause grain deformation. The adhesive thins out too much, leeches into the grain, and shows itself (normally at finishing).
Have you changed the tape removal process?
Have you changed from vegetable to animal adhesive?
Has anything changed with regards to your normal process? New tape dispenser, changes in how you press, did you change adhesives, etc.?
On the subject of zigzag stitching in the glue line, I have seen too-thin veneers sand through in a zigzag pattern because the threads cause minute bumps in the face, a defect worse than tape ghosts. I like tape!