sliding veneers

[David Zaret]

when i make passage doors, and use shop-sawn veneers over composite cores, it seems that i always struggle with the veneers sliding around during the draw-down of the vacuum press. i use packing tape, i use stretch wrap.... the only thing that seems to prevent creep as the top draws down is if i use brads or pins, but for obvious reasons, that's less than ideal. how do other people handle this? thanks.

-- dz

[John TenEyck]

I put a couple of pieces of blue tape on the bottom veneer at both ends and wrap it up over the substrate and top veneer before sliding it into the bag. The veneer and substrate sit on top of a carrier board with a piece of heavy duty window screen in between, and it all goes into the bag as one unit.

John

[Kevin Jenness]

I have less trouble since moving from a bag to a frame press. Centering the layup in the press helps. I normally oversize the cores and/or the veneers and top platen slightly and can't remember having enough movement to be a problem in ages. Sketch faces can need more precise placement, but tape, trimming after layup and prayer is all I can offer. Blocks pinned to the base platen or temporarily adhered to the blank might help if sized to allow for veneer expansion from glue moisture.

[Richard Coers]

I always make my panels oversized and also use blue tape. A little shift is fine because it is oversized

[Tom Bender]

Possibly use a little less glue and roll the veneer down prior to bagging it. This may spread the glue more evenly and give it a chance to tack up a bit.

[Mel Fulks]

Old timers used a few grains of sand to stop sliding.

[johnny means]

It's important to make sure there is slack membrane all the way around the panel. The veneers won't slide if pressure is only pressing inwards. It's when the bag starts being pulled and stretched into voids that you get lateral movement. It also helps to surround the panel with sticks of about equal thickness to fill in the voids around the panel.

[Thomas McCurnin]

I apply the glue by roller, and press onto the substrate, let the glue set for a minute or two, then clamp. It is less likely to move if the glue starts to set. In extreme situations, I have also applied the veneer, let it set, then removed it and reapplied it, then clamped it.