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Main Boards => The Bowyer's Bench => Topic started by: No beard on December 20, 2016, 09:57:00 PM

Title: Hot box - heat source
Post by: No beard on December 20, 2016, 09:57:00 PM
Hey guys,

I'm getting ready to make my oven and was thinking about the heat source. I have portable halogen work lights i could put inside. This would avoid wiring, etc. has any one ever tried this and had it worked?

Thanks,
Matt
Title: Re: Hot box - heat source
Post by: Robertfishes on December 20, 2016, 10:15:00 PM
They might get too hot and/or the heat might not heat evenly. I'm still using 4 100 watt light bulbs along with a 180 degree snap disc. In the warmer months the four 100 watt bulbs usually get about 165 degrees..
Title: Re: Hot box - heat source
Post by: LittleBen on December 20, 2016, 10:44:00 PM
If it is a box totally sealed to light all that should determine heat is input wattage since all the light is converted to heat eventually, as long as it doesn't escape the box.
Title: Re: Hot box - heat source
Post by: mikkekeswick on December 21, 2016, 03:18:00 AM
No they will give you hot spots.
100 watt light bulbs are great and a small oil filled radiator work perfectly.
Title: Re: Hot box - heat source
Post by: BMorv on December 21, 2016, 09:33:00 AM
I use 2 cheap portable clamp lights with 100 watt light bulbs.  I use it to dry out wood and those 2 bulbs get my hotbox to 120 deg.
Like you mentioned I didn't feel like wiring anything, and I had those laying around.  
IMO, Halogen lights get pretty hot and I wouldn't feel safe using them next to the combustible materials of a hotbox.
Title: Re: Hot box - heat source
Post by: die_dunkelheit on December 21, 2016, 10:18:00 AM
I use 4 heat lamps and a water heater thermostat. I place a heat shield along the bow on both sides so there is no direct path from the bulbs. It heats up super fast because the lamps are capable of a hell of a lot hotter than 180. This keeps me from just waiting and it stays right around 180 pretty much regardless of external temps because the thermostat just kicks it on/off.

I used the high heat wire you see under an electric stove top and 4 ceramic bulb mounts. The thermostat I'm using is also meant for high heat so the system is pretty much going to be good forever except the bulbs themselves. For the box I use the aluminized mylar backed flakeboard with the mylar facing the inside and when I'm doing a lot of work and want a more permanent box I add some 1/2" foam panels on the outside.

I seem to do a lot of random fiberglass or other composite work and use this setup for all of it so I get more out of it than an occasional bow.
Title: Re: Hot box - heat source
Post by: No beard on December 21, 2016, 10:57:00 PM
Thanks Guys. I'll wire it up to be on the safe side.
Title: Re: Hot box - heat source
Post by: Pago on December 22, 2016, 01:10:00 AM
I use a cheap space heater vented on both ends of the box, and a DIY controller.  Even heat throughout, auto temp and auto shut-off.
Title: Re: Hot box - heat source
Post by: goobersan on December 22, 2016, 07:40:00 PM
add a fan
add a fan
Title: Re: Hot box - heat source
Post by: Krasus on December 22, 2016, 09:38:00 PM
I use 4- 250 watt heat lamps. I have it wired up to digital control relay with high/low temperature settings.  I also have a small fan I put in as well to turn it into more of a convection oven so there are no hotshots but good even heating.