Hi I am considering building a "hot box".  Trying to heat a double garage with an electric heater to 25c and maintain it there for some time would cost a fortune in electricity so I am considering making a heated box into which I can place my parts to cure off.  I am currently trying to figure out the best way of making such a box. 
My current idea is to make a box from MDF, approx 900mmx900mmx1200mm and line it inside with 50mm Kingspan board.  In the front make a small window with a piece of standard 4mm window glass.  For heating I was thinking of using 4 50w halogen downlighters mounted to the top of the box and a fan mounted centrally to circulate the air.  For controlling the tempreture I have seen a digital thermostat on ebay http://www.ebay.co.uk/itm/Digital-STC-1000-All-Purpose-Temperature-Controller-Thermostat-Aquarium-w-Sensor-/181006904049?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item2a24da2af1
As a safety measure I am considering also using a thermal fuse in series with the lights, in case of failure of the digital unit, such as this: http://www.ebay.co.uk/itm/Temperature-operating-Thermal-Fuse-71C-NEW-pack-of-4-/231069891434?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item35ccd6bb6a

What do you think?  The main thing I am worried about is burning my workshop down.

Hi!.