How Improperly Sealed MDF Fails

[rcnewcomb]

Occasionally there are questions regarding if MDF can be used for an outdoor sign. I thought I'd post an example of how MDF fails. The following was made a few years ago as our shop sign. It receives full sun during the first half of the day. Obviously moisture and bugs are contributing to the failure. From the highway it looks OK but we will be replacing it soon with a new design and better color-contrast choices.

[myxpykalix]

This is not the typical mdf we use on our tables is it? That i didn't think could be used no matter what.

I saw something a long time ago and don't know if anything came of this but someone showed where they powder coated some wood or some material not metal and wondered if that would be an alternative for you?

[Big-Tex]

Even coated MDF would not be my choice. I just don't think it is good material for exterior usage.

[coach]

I make oak aquarium stands and the store that purchases them sells MDF powder coated stands. They are not real happy with them as they do not last. They look great though.

[frankwilliams]

If you want to see the extremes of how mdf takes on moisture, leave a small piece of 1/2" thick stuff out in the rain for a day. The next time you look at it, it will be 1 1/4" thick. Swells like crazy!

[Big-Tex]

You should see how MDF is made.
It starts with 12" of fiber and they compress it to 3/4".