Oven or reflector with infrared

[Travst]

This probably doesn't belong in the regular powder coat forum, so I stuck it here. As I posted before, I'm having trouble curing powder with the 1500 watt infrared lamp. I purchased the lamp instead of getting an oven because I wanted to do a few larger parts and didn't want to give up real estate in my garage. However, I can't get the parts up to the proper temp for curing.

I'm considering building an oven or a box to contain the heat from the infrared lamp. Has anyone done this? I did some searches and didn't come up with much. Specifically:

1. What design for a reflector would work best? I've looked at aluminum sheet, which would be easy to work with.
2. Would the addition of a reflector or box bring the parts up to the proper temp? Right now, my temp is about 220F and I don't want to waste time and money building something that won't work.

Right now, I'm leaning towards bending an arc of aluminum sheet and attaching the the edges to two parallel steel 1" x 1" bars that hold the lamp at the bottom, facing up. I've also considered putting in a spit or carousel to turn the part inside. I am also weighing the time and trouble spent on this vs. buying a cheap oven and modding it. I just hate to lose the money I spent on the lamp. Your thoughts?

[woody103]

A 1500 watt heat lamp is not enough. I have 2 2000 watt heat lamps and still have problems. I tryed the building a box thing with both heat lamps and it did not work that well. Took a long time, and alot of electric to get up to temp, and then still was not good heat.

If you are building a box or enclosure for heat lamps, you might as well go and build the oven for not much more.

JMO.......

[Travst]

Thanks for sharing that info. I suspected as much... I wonder why these units are sold for curing powder?

[sdold]

I've wondered the same thing. People go to a lot of trouble to make the temps inside ovens uniform, with fans, fancy thermostats, etc. all designed to get the entire part to a certain temp and hold it there for a certain time. Then they offer these IR heaters to coat big items, as if getting the part hot on one side and warm on the other (and on the edges) will be good enough. They might be OK for helping to cure wet paint, but I don't get how they could possibly heat anything big evenly enough for a good cure job without some areas being under cured and some over cured. Maybe someone here has done it, if so, I'd really be impressed. I have never heard of any PC business using them.

Putting an IR curing lamp inside an oven makes no sense to me because ovens need convection heat inside, not IR. The air needs to be heated. Maybe it would work in a half-assed way if the inside of the oven was lined with mirrors.

[Travst]

I did a bit of experimenting last night. I took aluminum foil and lined a box with it and put the parts in it. I noticed no significant difference in temp with the box. I'll probably just use the lamp for curing painted items.

Now I have to fuss with buying/building an oven. I'm looking at taking an oven and removing the top since the range isn't needed, and adding a box on top to extend the unit. Sort a "pregnant upwards" direction rather than "pregnant outwards. This seems like something that would be relatively simple perhaps with a few substitutions like a PID for more precise control.

Geez, I've been hanging out here too long... the term "PID" just came out sort of naturally like I really knew what I was talking about. Seriously... my head hurts from all this meditation on ovens and the like. I want to get back to restoring my Jag.

[glennpd]

I have been toying with the idea of two galvinized garbage cans. One 50gal and one 30gal. Set the 30 inside the 50 suspended with some firebrick. line the airspce between the cans with oven insulation (J. E. S. industries) Use the two heat gun method through hole cutr through both cans, us a remote oven thermometer. use a hanging wire run through the inner (30gal) lid to suspend the item. Line the inner (30gal ) can with HD aluminum foil. Seems like this should work for a lot of parts.

[Travst]

I bought an old oven last night for $25, so I'm moving forward. The next step is wiring the garage for another 220v circuit. Unfortunately, the breaker box in the basement is full. On the plus side, the main breaker is attached to my garage. I'm going to consult with my mentor Freddy to figure out the best way to wire up my double oven setup I described above.

I'm wondering if I actually need two 220v outlets if I stack two ovens. As I plan to remove the top of one and the bottom of the other to stack them, I'm considering leaving the top element in the top oven (broil) and wiring them into the same temp switch... in other words, using only one of the oven control units or even substituting a PID. Wouldn't one 220v outlet work to support two elements? I'm going to look at the various calculators to try to figure it out.