InsideDarkWeb.com

Is sealing wood with urethane or the like enough to avoid wood movement?

Will a solid wood table top still move if it is finished from all sides with polyurethane or some other water resistant finish?

Does that depend on temperature as well? Assuming temperature differences are big enough comparing to when wood was finished (furniture left outside for example).

Is that calling for trouble in case of incomplete seal or when finish gets inevitably breached by normal wear and wood starts to take up moisture again?

Woodworking Asked on July 14, 2021

2 Answers

2 Answers

Will a solid wood table top still move if it is finished from all sides with polyurethane or some other water resistant finish?

Yes.

You can, in theory at least, completely seal off wood from the elements but it's really only possible using epoxy and even with that it must be applied at a substantial thickness with no pinholes or gaps in the finish.

Does that depend on temperature as well? Assuming temperature differences are big enough comparing to when wood was finished (furniture left outside for example).

No.

Wood doesn't expand and contract much with changes in temperature only (not enough to care about).

The reason temperature generally matters is that higher air temperatures often go hand in hand with higher humidity, lower temperatures with lower humidity, and it is its internal water level that makes wood change dimension.

Is that calling for trouble in case of incomplete seal or when finish gets inevitably breached by normal wear and wood starts to take up moisture again?

That would depend on if you designed the piece so that wood movement isn't allowed for :-)

It's an attractive idea, that we can seal off wood from moisture in the air to make it as stable as possible, but in reality it's a PITA to do and it's just not necessary. Only where it hasn't been allowed for is it an issue..... such as in cheap furniture built from dimensional lumber using bad plans provided free on the Internet -_- It's worth remembering that virtually everything that's ever been built from wood expands and contracts and it's not a problem because allowance has been made for it.

Where you want or need to make something that doesn't change dimension you shouldn't use wood, not solid wood at least. MDF or plywood are very good options to make something that looks like wood but is more dimensionally stable and of course there are now a wealth of synthetic materials to pick from as well.

If you need pointers on how to allow for movement see this previous Answer:
What general considerations do I need to take into account for wood movement?

Correct answer by Graphus on July 14, 2021

A finish is not a hermetic seal. It may slow wood movement; it will not prevent wood movement.

Humidity matters much more than temperature.

Answered by keshlam on July 14, 2021

Add your own answers!

Related Questions

How do I calculate a miter angle?

1  Asked on March 27, 2021 by mr-mascaro

     

What is the mimumum bend radius for 6 mm Medite Tricoya Extreme MDF?

0  Asked on March 25, 2021 by petaspeedbeaver

   

What grit sandpaper should I use on my drumsander?

1  Asked on March 24, 2021 by wizlog

 

Track hardware for hanging plywood panels

1  Asked on March 10, 2021 by fakeer

 

Finish for MDF Worktable

4  Asked on March 7, 2021 by azulshiva

       

Remove and replace inset wooden handle

4  Asked on March 7, 2021 by daniel-k

   

Levelling off a surface for veneer

4  Asked on March 4, 2021

   

Using a 5/8 dado stack on a “30mm” arbor

2  Asked on February 28, 2021 by ryanjdillon

   

Ask a Question

Get help from others!

© 2021 InsideDarkWeb.com. All rights reserved.