Wood Veneers: Gluing up your work
Spreading the Glue:
For hide or PVA glue pour some glue in a tray. Brush or Roll on
with a hard rubber roller - a nice even & THIN glue line. Never
apply glue to the veneer itself - only to the substrate.
Hide Glue:
If the glue gels over it is not a problem. The veneer will not stick,
so align it to the right position, cover it with craft paper and
with your iron on medium, heat the entire surface to be glued. The
heat from the iron will reactive the glue. Remove paper and use
a veneer hammer to press the veneer into place while the glue is
still hot and liquid. Work from the middle to the outside, as a
means to drag air bubbles out from under the veneer. Work quickly
before the glue cools, re iron if necessary..... trim veneer as
needed.
PVA:
Place veneer on substrate, and with a small roller press down the
veneer to the surface, eliminating any aire bubbles as go. Cover
with paper, add a scrap piece of plywood or MDF on top and clamp.
It should be clamped from the center out to force any air bubbles
or excess glue to the outside. Clamping should be every 3-6".
Vacuum Bag Presses are great to use, because they will exert an
even force across the entire surface. Just make sure that you tape
the veneer into place and cover with kraft paper so it does not
get stuck to the vacuum bag in the gluing process. Whatever method
you use make sure that it is left in the clamp for the full drying
time as dictated be the glue that you are using.
For small projects, you can actually iron on the veneers. It works
something in the reverse of hide glues, in that the iron, evaporates
off the water in the PVA glue, thus speeding the drying process.
You do have to be careful with the veneer slipping though. The heat
initially makes the glue very slippery and the veneer wants to head
south..... make sure it is infact positioned correctly before the
iron fully dries the glue.... at which time you CANNOT reposition
it.... practise on a scrap first so you know what to expect.
Contact Cements:
Remember that contact cements work a little different than traditional
glues. It must be spread on both the veneer and the panel. Some
of the newer glues, are designed for spray applications, if not,
spread using a notched trowel, or my choice a piece of arborite,
and with a back and forthe troweling technic cover your entire surface.
It is very important NOT to leave blobs as this will show through,
especially the thin veneers, and leave bulges in your work. Set
asside for both to thoroughly dry.
Once dry, lay a piece of thin paper on top of your panel and gently
lay the veneer over top, positioning it correctly, trying not to
exert any downward pressure on your stack. Gently pull out the paper
from between the veneer and panel and press into place as you go.
Hammer down into place to assure good contact.
Other Tips:
When gluing to solid wood, always glue to the heartwood side of
the board, since the wood always has a natural tendency to cup towards
the sapwood, and the veneer will have a couterbalancing effect.
Better yet I would suggest you glue the reverse side of your substrate
as well, with a counter balance veneer (backer veneer) even if the
back side will never be seen. This should be done at the same time
as gluing your face - especially in a hot press. This evens out
stress on your outer skin and helps prevent future problems with
your finish...
Use MDF as a substrate whenever possible, to obtain a more stable
core... of course we all know that MDF is not good if joinery is
involved, so keep the whole project in mind when making these decisions
You can use a "decorators size" or thinned glue to seal
the back of the veneer, so that it absorbs less moisture thus less
shrinkage and drying issues.
Roughing up the surface of your substrate, will allow for better
glue adhesion.
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