Hot Box Issues?

[Michael Scott USMC]

Has anyone else ordred a kit from Bingham's and the thermometer doesn't work correctly with the hot box?  It gets up to about 175 degrees the first time you turn it on, then it shuts off, cools to about 120 degrees and only gets back up to about 160 after that...  I tried lowering the location of the thermometer since heat rises, but still no joy.  Does anyone have a clever fix for this?

[Michael Scott USMC]

And once it hits 160 it shuts off again and goes back down to 120.  I'd say it spends the majority of the time in the 130-150 degree range.

[macbow]

That is pretty much the way thermo switches work.
If you want to check it out further call Binghams. If it needs to have a,higher range they,should help you.

[Michael Scott USMC]

Does that temperature range sound like it would work?  I just don't know if that's too low for it to work properly.

[Trux Turning]

If you are using smooth on that will work (it will cure without heat in 24 hours). It does seem like a big drop in temp though-I'd give Binghams a call to see if that's normal for their switch.

[carpin'mark]

I have not used the Bingham thermostat so I don't know what range it may be set to go on and off, but I do know I had at least a twenty degree difference between the upper half and lower half of the hot box. I dropped in a small fan, run it on low and now it circulates the air and I can maintain a consistent 170F through the cure, had to play with the wattage a little to get it just right.
Hopefully Bingham will have a suggestion where to place it to get a more consistent read.

[Robertfishes]

I also built my oven using Bingham specs and snap disc thermostat. I drilled a hole thru the side and put a meat thermometer next to the thermostat. In summer temps I see it go up to 180 and hover around 160 most of the time..but during cold days it would stay around 145-160, I replaced the 100 watt bulbs with 200's and then it would shut off at just over 180 and come on at 150.. I keep thinking about putting a small computer fan in the oven, Radio Shack has them for cheap..my old computer in the shed may get parted out tonite...I have concerns about my oven temps too, the meat thermometer and placement of my thermostat may not be the best..

[carpin'mark]

I use a meat thermometer too, if it's a decent one I believe they are pretty accurate. I have two small holes drilled in the long side of the box, one about 1/4 from the top, and about a 1/3 from the bottom. For me, this gives the range right where my mold is sitting and I can check periodically.
Takes a little playing with bulb wattage, but once set up, it works pretty well.

[Robertfishes]

I also drilled a hole in the middle of the lid, between the 2 center light bulbs..I didn't notice much difference maybe 5 degrees hotter? Didn't check the bottom half, I assume the bottom of oven would be the least hot place like yours. The little fan you (carpin mark) are using should help even temps out..I need to  insulate my oven better..I have some 1/4 inch double foil foam left over from another project, if it will take the heat it should keep me up to 180 in the colder months with 100 watt bulbs

[Pat B]

I built my hot box from Binghams plans and added the thermostat they offered. The box stays about 168deg and would get hotter without the thermostat. I have insulated the box with 1/2" foil lined foam board and that helped plus added a small fan. I use a candy thermometer at each end on the box and they both read close to each other. I made this box to build a Bingham kit years ago but now use it for a drying box for selfbows. I added 2, 1" holes, one at the top of one end and one at the botton of the other end to allow the moisture from a stave a place to escape. I plug the holes for curing out glues when needed.

[Al Dean]

If you lined the box with foil, shiny side out it reflex heat just like light.  Your object being baked may be hotter than the air temps you are taking.

[goobersan]

American Science and Surplus has a 120V fan that I use. McMaster-Carr is where I got my snap-disc. 160-180 degree. with the fan, my box temp hovers around 174-176 degrees. PM me about the snap-disc. I may have an extra one

[canopyboy]

Same problems, going to try putting in a small fan and seeing if things aren't better.  I know that I have my binghams thermostat higher in the box than my thermometer, so makes some sense.