Table project finishing

[Harry Niemann]

Making a parquet top coffee table to be used in West Palm Beach FL (High humidity area).Is it best apply finish to the underside of the top or leave it unfinished to allow breathing. Red oak on plywood.

[scott vroom]

Making a parquet top coffee table to be used in West Palm Beach FL (High humidity area).Is it best apply finish to the underside of the top or leave it unfinished to allow breathing. Red oak on plywood.


A description of "red oak on plywood" would be helpful. What type of plywood and how thick will the red oak layer be? Will the table be attached to an apron? Water or oil base finish?

[Harry Niemann]

Red oak parquet 1/4" on 1/2"" plywood poly finish

[Wade Lippman]

About half advise to finish all parts the same so it absorbs or gives off moisture evenly. The other half say it doesn't matter and you can ignore the bottom.
Personally I finish the bottom; doesn't seem like it can hurt.

With humidifiers in the winter and A/C in the summer, it doesn't much matter what you do. 10 years ago I ran a drawer front the wrong way because it looked better; figured I would fix it if it mattered. Looks and acts exactly the same all year round.

[scott vroom]

Red oak parquet 1/4" on 1/2"" plywood poly finish

Still not clear on what you're doing. Are you making your own parquet by laminating 1/4 oak onto 1/2" ply is this a sheet good product that you've purchased?

Laminating a thick layer of hardwood onto a sheet of plywood for use as a table top can be a disaster...the hardwood will move seasonally and cause the stable ply to warp. Also, what table design? Are you attaching an apron to the underside?

You also didn't clarify if WB or solvent base poly.

[Harry Niemann]

The project is a 4' square coffee table with 150 + !/4" red oak parquet pieces glued to 1/2" plywood with polyurethane construction adhesive. There will be a 4" apron around the edge. The finish will be oil based polyurethane. Should I finish the underside of the plywood?
I will make all of the parquet pieces.

[Howard Acheson]

Do you mean you are planning to glue hardwood blocks to a plywood substrate? If so, you will end up with splitting and/or warping. You can firmly glue solid wood to a composition substrate. The solid wood will want to expand and contract with changes in relative humidity. However the composition material substrate will not move with relative humility changes. This will cause stresses in the panel leading to damage.

Applying a finish will not negate the propensity for damage.

I suggest you re-think you plans.

[Dave Egan]

Harry,

I was planning on doing a similar project for my daughter. I was going to do a herringbone pattern but everyone told that the 1/4 wood would move too much. I am now thinking about doing it with veneer using yellow glue and a hot iron. I am still working on testing with the veneer. My first attempt was not good but an instructor told me it would be a good application for this veneering technique since I do not have access to a press.

Dave

[Kent A Bathurst]

I suggest you re-think you plans.

+1. This won't turn out well after one seasonal cycle of humidity. The plywood will not expand/contract. The 1/4# wood will move - and there is nothing you can do to stop it. If you get down to veneer thickness - like 1/16" - then you can win that battle.