Hi Jocko,

Love the work you are doing with UV and powders.

Now I am not at all sure here, so maybe an outdoor test with fire safety equipment would be a good idea, but I suspect that the powders

baking soda - salt - baking powered - sand

may not be as flamible as flour, sugar, saw dust, iron filings, etc.
So if you need to use high wattage bulbs again, maybe these would be the powders to try?

Be safe, be creative, and have fun!