MATERIALS - How To Make A Drying Box
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Description: Oil paintings cure through oxidation rather than evaporation (as in watercolor and acrylic). Sometimes waiting for an oil painting to cure is a frustrating experience - and applying new layers and varnish too soon is a very risky business, leading to lifted sections, beading, and difficult paint handling. Our friend Marsha Piper offered us this clever solution, an age-old process for accellerating drying time by using ultraviolet light. At the bottom of the post, see the letter from George O’Hanlon of Natural Pigments, when asked about the safety of this method.
- Get a large box, like a shipping container, and line with heavy duty aluminum foil. The box should be at least 27″ on a side - slightly larger than the lights in step 3. Marsha’s box is 30″ x 38 1/2″.
- Make a lid for the box, also lined with foil. The lid should be sturdy enough to handle the attachment of the light fixtures. Marsha used beadboard. Make sure the lid can be propped up with a dowel or similar to allow heat to escape.
- Purchase 4 UV light fixtures, 22″ or so, available at any hardware store. Attach 2 to the lid, top and bottom, and 2 to the inside of the box, side to side. There should be a light on each of the 4 sides.
- For ease of use, gather the 4 cords together and attach to a single switch-controlled power strip.
- Place a painting inside, turn it on, prop the lid an inch to allow heat to escape, and voila! Paintings cure overnight with no wind, no dust, no bugs!
Here is George O’Hanlon’s letter explaining he uses a similar method:
Dear Marsha,
I constructed a similar type of box to accelerate the drying time of oil varnishes on paintings, except that my light box contains four 40-watt actinic lamps, which are fluorescent lamps that have the same color spectrum as sunlight. These lamps are similar to those used in professional marine aquariums. I am sure that these lamps put out much more UV light than the ones you use in your light box. However, I have placed many different types of paintings and exposed them to this light for hours, being careful to watch the temperature inside the box.
Unless you are exposing your paintings to days of intense light, I cannot see why this would pose any problem to your painting. The only caution is to not let the temperature inside the box exceed 100° F for a long period and to avoid excessively long exposure. Of course, if you use fugitive pigments, their lightfastness may become compromised with long exposures.
George O’Hanlon
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Does it actually cure the painting to the point where you can varnish it?
That’s a cool design. I built one, but it is just a large wooden box with a glass top that is hinged. It works during the day, outside rain or shine, there always being UV rays.
Your design is a 24/7 version. I think I might build one of those.
Mine worked best when using amber in my medium, which is really affected by UV rays. However, I’m not using amber anymore. I’m wondering how well the UV rays work on non-amber’d paint?
I personally can’t do without my drying box, now.
No matter what medium I’m using, I put the panel/canvas in the box overnight - ready to work on the next day. The only medium that’s taken longer than overnight to dry to the touch, is stand oil - like stand/turps. Great medium and just takes a day or two longer than usual to dry. I even put my painted Munsell spheres in there, along with value/chroma sticks - works like a charm!
One of the biggest benefits besides the drying part, there is no dust flying round inside the box - I made my lid a bit bigger than the box itself, so no errant dust particles could enter.
Keep in mind I paint in fairly thin layers - so not sure how long heavy impasto work would take.
I see that Gregory also asked this but I’d like to confirm the answer. I’ve read that it’s recommended that a painting be allowed to dry for at least 6 months before varnishing it. Does the drying box allow curing to the degree that varnish can be applied within a few days?
I remember reading something about the old masters warning against drying paintings in direct sunlight as it could cause cracking of the paint film.I wonder if a device like yours could cause similar damage.Anyhow, you’ve presented an interesting solution to an age old problem.