On Mon, 22 Feb 2010 17:12:55 -0600, Art Greenberg wrote:
I suppose you could use scraps of the substrate positioned to support
the veneer, but you will have to figure out how to keep everything in
place until the vacuum is fully applied, and you will need to put packing
tape or plastic on them to keep glue that is squeezed out from sticking
to them.

I've always made the substrate a bit oversize and cut the veneer to
match. After the glue-up is complete, I trim to size. But I haven't
done anything like what you're contemplating.

One other thing. You can (and should, if the substrate is flat) use a
solid platten on both sides of the assembly. If the platten is thick
enough, and larger than the veneer, you can use veneer that overhangs
the substrate by a small amount.

If the substrate is curved (e.g., you are making bow fronts for
drawers), then you'll be using a "soft" platten, and the veneer really
should not be larger than the substrate.

--
Art Greenberg
artg at eclipse dot net