Planning on doing some filler work on the Demon today. I will turn the heat on in the shop to get the air temp up to comfortable 55-60 degrees but was wondering if I could apply filler to the cold metal (30 degrees)?

its not advisable, but can, and is, done. You can use a little more hardener to accelerate the process, but you're also creating a more brittle filler OR risking an incomplete cure.

Couldn't you at least blow a hair dryer on the areas you're going to fill for a few minutes first?

I will turn the heat on and wait awhile for the metal to heat up (I can apply spot heat like you mentioned too).

Thanks for the advice

Set one of these up next to the spot your working on. They release a lot of heat and will keep the metal plenty warm enough. Any hardware store should have them and they are dirt cheap.

http://ecx.images-amazon.com/images/I/518XWMAZFML._SL500_AA280_.jpg

I got some of those red heat lamps and put them in a clamp on drop lamp socket. I used it to warm the metal and help dry the bondo. You can clamp them to the car, chairs, sawhorses etc to position them just right.



Plus this




Is cheap and works great.

heat the metal up first or you risk the chance of condensation forming between the filler and the cold body panel as the filler set's up.