Attaching solid wood panel to plywood?

[Juss1]

Making a tabletop and I want to use some the 4/4 lumber I already have instead of buying thicker stock.  So I was thinking of making a panel and building it up with plywood and edge banding with solid stock?  Can I just glue the panel to the plywood?  Expansion problems?  If not, how would you suggest I do it?

[mike4244]

Making a tabletop and I want to use some the 4/4 lumber I already have instead of buying thicker stock.  So I was thinking of making a panel and building it up with plywood and edge banding with solid stock?  Can I just glue the panel to the plywood?  Expansion problems?  If not, how would you suggest I do it?

Make the panel, attach from bottom with washer head screws in a slot thru the plywood. The screws in the center of the top can be tight , the other slots just snug the screws so the panel is flat but not hard tight. You should not have any problems with expansion done this way.
mike

[DogwoodTales]

If you’re just thinking about center support how about just making joists (so to speak) with the plywood to support the top? I’m thinking they will be hidden by skirting, so maybe that won’t work for your design. But it would decrease the overall weight of the table as well which may or may not be desired.

[WoodTinker]

Making a tabletop and I want to use some the 4/4 lumber I already have instead of buying thicker stock.  So I was thinking of making a panel and building it up with plywood and edge banding with solid stock?  Can I just glue the panel to the plywood?  Expansion problems?  If not, how would you suggest I do it?

Plywood is real wood glued up alternating the grain between sheets.  You can glue lumber to plywood and edge-band. Taking care not to show the plywood.

Better would be to glue veneer (same species as the 4/4 lumber) to the bottom side too, and then edge band after.

[Handplanesandmore]

Plywood is real wood glued up alternating the grain between sheets.  You can glue lumber to plywood and edge-band. Taking care not to show the plywood.

Better would be to glue veneer (same species as the 4/4 lumber) to the bottom side too, and then edge band after.

While plywood is also wood, it does not move (expand or contract) like regular lumber. Depending on the lumber and size of the panel (tabletop), if you glue it to a plywood and the lumber moves in response to humidity change, but not the plywood, there is gonna be a problem.

Size matters here. If you glue a lumber strip to a plywood base, you may get away with it, but not a 4' wide plank on a ply sheet in a non-humidity controlled setting.

Simon

[Alan S]

Wood tends to expand and contract crosswise to the grain, but not lengthwise.  You can constrain this expansion and contraction by glueing layers perpendicular to one another, as in plywood, within limits.  As each layer of solid wood gets thicker, the force of the expansion and contraction increases, as does the stress on the glue.  If the force is more than the glue can hold, it will tear apart: to be safe people generally stay at or below 1/8" thick, but much thicker layers can be constrained under some circumstances, as in solid core plywood. 

If the solid wood is only on one face of the plywood, it will tend to bend one way in humid weather, and the other way when dry.  Putting the same thickness of solid wood on each face, running the grain the same direction, balances these stresses so it should not warp.  But the thinner the layer of solid wood on each face, the lower the stress on the glue bond.

But why not just use the 4/4 stock for the tabletop, and make the edge thicker for looks? You may not need the plywood.

[FrankAtl]

But why not just use the 4/4 stock for the tabletop, and make the edge thicker for looks?  You may not need the plywood.

This was going to be my question.

[Willyou]

This was going to be my question.

I agree. You don't say how big your table top will be, but for a typically sized top, 4/4 lumber would be adequate. If you want it to look thicker then thicken just the edge. Saves wood. Saves $$. Saves weight.