What is 'laminating' and how is it done?

[Pakaderm]

I keep reading about 'laminating' sheets of MDF together, or other materials, but I don't really know what it means. Is it simply face-gluing two sheets of material together or something more involved.

Could someone explain exactly what it is, and the proper techniques/materials for 'laminating'?

Thanks,
-Pak

[ssmith1627]

Yes, basically face glueing. Put two or more layers together to make one thing.

Often it's done for curves. One piece of 3/4" thick material isn't going to bend very well. But take 3 layers of 1/4" stock and you can bend them to a certain shape. Put glue on them, bend them to a form and clamp them in place and when they dry they'll hold that curved shape.

Veneers and counter tops are laminated as well. The more pressure the better the hold the two layers together evenly. For veneers, a lot of people use vacuum bags because you can get tremendous pressure that way. A layer of plywood for example with a layer of veneer glued to it and then a layer of MDF (no glue) to press the veneer firmly to the plywood. You want that pressure there so it bonds evenly all around.

Steve

[crokett]

Laminating is face-gluing two pieces of material together.

Proper technique somewhat depends on the glue being used but is mostly about ensuring adequate glue coverage and clamp pressure. You want to get the glue onto both surfaces so that it completely covers them. For contact cement, you would wait till both were tacky, then stick them together. For a white/yellow glueup, you would stick them together then clamp them. Clamping methods vary - vaccumm systems, clamps/cauls or I've even used heavy weights. If I were laminating sheets of MDF chances are one side would be hidden so I'd glue it up then just put screws in.

[DonHo]

Yes it is just face-glueing two sheets of material together. Usually when one is doing this it's for the purpose of making either a work bench top or router table top. If that's the case one side (the botton side) won't show so the easy way is to use dry wall screws from the bottom side to pull the two pieces together and you won't have to use clamps for the glue up. If you are going to use the glueup for a router table make sure not to up any screws in the area where you'll be cutting the opening for the router plate. Also when screwing two pieces of MDF together, sometimes the screw will pull up fibers from the bottom piece which might cause problems with getting the two pieces pulled together tight. You can avoid this by clamping the two pieces together (no glue) and driving the screws or drilling pilot holes thru the top piece far enough to mark the bottom piece. Then seperate the pieces and countersink the holes in the bottom piece to allow room for the fiber without causing the problem.
DonHo

[Pakaderm]

Great guys, thanks for the input!

-Pak

[Slik Geek]

Extending this thread...

Any suggestions on clamping curved laminations? I saw one idea that had numerous rubber bands stretched across the form to hold the laminations in place while the glue dried.

Also, do you usually do one layer at a time (glue and set), then another layer... or do you do a bunch of layers (working quickly because the curve isn't right until all layers are in place and set)?

[cabinetman]

Extending this thread...

Any suggestions on clamping curved laminations? I saw one idea that had numerous rubber bands stretched across the form to hold the laminations in place while the glue dried.

Also, do you usually do one layer at a time (glue and set), then another layer... or do you do a bunch of layers (working quickly because the curve isn't right until all layers are in place and set)?

That would depend on how thick each layer is and the degree or complexity of the curve. On very thin sections they may have the tendency to slip around. As they get thicker they may be less "bendable" necessitating one or two at a time. In the case that there are "add ons", the last one to be clamped up should be cleaned thoroughly to give the next layer a good smooth surface to adhere to.

But to answer your question, it can be done either way, as long as they are held in place to the form, by either clamping, taping, banding, or vacuum methods.
.

[BrazosJake]

Extending this thread...

Any suggestions on clamping curved laminations? I saw one idea that had numerous rubber bands stretched across the form to hold the laminations in place while the glue dried.

I just use the waste cutout from the form as a caul to clamp down on top. Another method, if your form is wide enough, is to drill holes big enough to take the end of a clamp so you can clamp the lamination down to the form.

Rubberbands and even spring clamps will work for gentle curves, where you don't need a lot of pressure to make the lams bend to the form (bowyers commonly use them). Face laminations are all long-grain to long-grain and don't need tons of clamping pressure.

[JR]

Check out how David Marks does bent-wood laminations here:
http://www.diynetwork.com/diy/shows_..._26962,00.html