Medium Density Overlay, MDO
Found in hardware stores, this sign painter’s material provides proven stability.
Although you can draw or paint directly on the MDO panel with oils, watercolors, or dry drawing media, we recommend a barrier for most applications.
When painting with any acrylic paint, medium, gesso, or ground, we recommend applying 2 or more coats of Gloss Medium first to reduce support induced discoloration.
For oils, apply 3 or more coats of Acrylic Gesso to reduce oil absorption.
Grounds (including those for drawing media and watercolors), gels, and pastes can be applied to alter the surface’s absorbency, durability, or texture.
Video: Support Induced Discoloration (SID)
Article: Medium Density Overlay
Tech Page: Surface Preparation
Absolutely loved this deep dive into painting on MDO! As someone based in New Zealand, where our weather can be quite unpredictable, the insights on MDO’s durability and moisture resistance are particularly valuable. It’s great to know that MDO, with its resin-impregnated overlay, offers a stable surface for both acrylic and oil paints, making it a reliable choice for outdoor projects .
Your recommendations on sealing and priming are spot-on. Given our high humidity levels, especially in coastal areas, ensuring proper edge sealing and using high-quality primers is crucial to prevent moisture ingress and potential delamination. The tip about applying multiple coats of Gloss Medium to reduce support-induced discoloration is also very helpful .
I’m inspired to experiment with MDO for some upcoming outdoor mural projects here. Thanks for sharing such comprehensive information—it’s a fantastic resource for artists looking to ensure the longevity and quality of their work in challenging environments!
Thanks for your note, Zeolis. Just as you say, if one plans to use MDO outdoors, they should take steps to seal vulnerable edge grain. Cover/fill the entire edge grain with a high-quality filler and sand it smooth. Soften all sharp edges of your panel with sandpaper to ensure a consistent paint film during application. Then, prime the entire panel with a high-quality outdoor-rated primer before application of your paints. A varnish or clear topcoat is recommended for greatest durability.
Best of luck out there!