Making a cure oven, advice requested.

[Reuben Contineli]

Hi,

I am moving my shop, Virginia where it snows often, and will need to paint my designs outside and cure them outside under a roofed pourch area. To help compensate for the weather I am thinking about building a curing oven and can use some advice.

My designs are ~12" x ~12" to ~10" x 24", plywood, painted with rattle can spray paint.

For the oven, I am thinking about building it 2' wide, 2' deep, and 4' tall, with two shelves, with four heat lamps per shelf facing down into four quadrants, made of 3/4" plywood, lined with tinfoil. This will allow to cure eight smaller designs at once.

The bulbs I am looking at are 125w infrared heat lamps. (http://www.ebay.com/itm/Westinghouse...item27e53df2a8)

There will be one foot between the design surface and the heat lamp.

Will this oven work in most weather? Is this enough heat? Is the spacing between the design and bulb too much or too little? Do I need to add a layer of insulating material around the main structure? Any other thoughts are welcome!!!

[Art Mann]

My opinion is that you need to cut waaaaay back on the amount of heat you are putting into that little box. Even one 125W bulb will eventually heat the interior to dangerous levels. In addition to heat, you also need a fan for circulation to purge the hydrocarbon vapors.

[Scott Holmes]

Heat does not normally cure rattle can paint (Unless you are using a specialty paint that uses heat to cure). Most oil based finishes cure over a period of ~30 days. Warmth and air flow will speed curing. Oxygen is the most important ingredient for most oil-based products "curing". I would say, once the paint is dry to the touch; one bulb for heat and a good fan for air flow would work very well..

[Reuben Contineli]

Thanks guys. I will cut the heat back down to two 125w bulbs, one for each shelf. With your advice, I will add an internal fan for air circulation. Also, I am thinking I will add a set of fans in a push pull configuration and a Arduino controller that will clear the air out of the box every 15 minutes or when the temperature reaches a set point.

[Scott Holmes]

Seems like a lot of extra setup; a fan blowing across it with fresh oxygen and a reasonable temp would be fine. Virginia is not that cold all year, is it? Most finishes like 72° or more; anything much north of about 95° may cause other problems. I would opt for the fresh (oxygen rich) air, over the temp.

NOTE: depending on the finish you are using; acrylic for example may not even be a finish that "cures" many of the water-based finishes are coalescing finishes. Different animal all together

[John TenEyck]

I run my 9' x 3' x 4' drying kiln at 110 F with 3, 100W incandescent light bulbs, though it does have 1" exterior foam insulation. So, as others said, you won't need very much heat at all for the little box you want to make. I would be more inclined to change your design to include a single light bulb at the bottom and a vent hole at both the bottom and top, with a shutter on the top one so that you can control the amount of convection passing through the box. That will satisfy your need for fresh oxygen to get to the finished parts in the simplest way. If you insulate the box, I bet a 60 watt incandescent bulb will be more than enough, probably too much. Hang a thermometer through the roof, too, and change light bulbs, if required, until you get the temp. in the correct range, say 70 - 90F.

John

[Reuben Contineli]

Solid advice guys, saved me some time expensive mistakes in my project, thank you.

I like the idea of allowing natural convection to occur and controlling it with a simple shutter. I will try this design first. My goal is to be able to cure my items in a day or two for ASAP shipping even when it's snowing outside.