Wow Roy, I expected you to say you guess it is OK.
Clint, I get 85-90 F and 20-30% Humidity this time of year when it is 35-40 F and 60-70% most of the time outside of the box (in the attic). That is with 3 40 watt bulbs. That is with the end pieces vented just a bit, about a 1/2" space. If I want it hotter, I throwz a moving blanket over it and keep the ends closed up. Then it reaches 100. Changing bulb wattage would give you higher temps yet, if you wanted. I dont use a thermostat, but it stays surprisingly stable when slightly vented.
I had a couple particle boards given to me. I hate particle board because here in the northwest the moisture kills it in no time. But then I looked at the pre-sprayed lines on the thing and thought hot box! I figured the particle board would hold up for a long time as long I kept the box in steady use. This was made from one 8x4' particle board, a broom handle, and some 2x4 and 1x1 scrap. I got the fixtures and wire for next to nothing at second hand building supply store.
In the pics I have a 2x4 as a baffle (resting on the three pegs) I switched to a 3/4" x 6" wide piece of pine running the length of the box and it suits the box much better.