Thursday, March 5, 2009

Hazards of Masonite

I just ran across the following article in Robert Genn's older weekly letters. I have been painting on gessoed, tempered masonite, and noticed that others are painting on masonite as well (not sure if it's tempered or not), so I thought you may be as interested as I was in this article.

Untempered Masonite is indeed fading from
shelves. Further, the quality varies--corners can crumble away
like oatmeal cookies. Sealing and reinforcing with something
like acrylic medium doesn't always do the job. Some painters,
driven to tempered Masonite, have seen other alarms go off.
This support, while harder, is simply loaded with acids that
gradually seep through several layers of gesso. After a few
years the painting surface will certainly be foxed. The estate
of a deceased painter friend was mostly ruined by tempered

Glad I didn't sell most of those paintings. May have a couple of redos in my future!


  1. Wow, I didn't know this about 'tempered'. I was just about to buy some, so thanks - I think I will stick with canvasboard and gallery stretched.

  2. Hi Vern,

    When you say "tempered masonite" - how is that different from non-tempered masonite? As you can tell, I am not in the know when it comes to building materials! :-) Many artists use "gessoed ampersand" - is that the same thing?

  3. Pattie and Joanne, I just did a little research on this and found that ampersand is indeed a tempered hardboard, but their more modern process eliminates any of the acidic problems. They use vegetable based oil, and very little before they bake the sheet. It is generally accepted to be museum quality. It is the construction grade masonite that I am concerned with.

  4. Thank you for the info, Vern.
    I have "tagged" you!

  5. Thanks for the info, Vern. I've heard that you have to seal all the surfaces with acrylic paint; otherwise, the board crumbles in time as you mentioned.

  6. Thanks Edward. You honor me!

    Hi Akiko, thanks for that info. I will do that in future. I have used acrylics in the past, but perhaps not as thick as needed.

  7. Thanks from me too! Glad I switched to Ampersand when after I sold a few paintings with Home Depot masonite! I won't be tempted to go back to save money!!!!

  8. Very interestng! Although I think the untempered (usually lighter in color ) is okay, still, right?