Hi there adeep42,
I've used Hammerite, Rustoleum gloss and Rustoleum Hammered finish on various components of Bottlehead Kits over the years. I've never had a problem with a soft finish with any of them, but generally, work and other to-do's have allowed a week or two for curing of paint. Deluk's suggestion is a great one; I've painted onto plates warmed by the sun and let plates sit in the sun after painting to accelerate curing.
I just last week painted parts for my Kaiju with Rustoleum Hammered finish (top plate, transformer bell) and Rustoleum gloss black (transformer, tube socket retaining rings). The top plate and bell were painted outside on a sunny day, whereas the gloss black parts were painted in the garage on cloudy but not cold (about 65 deg F) day.
I'd say the top plate and bell were ready for assembly within a day or two (after my patented 'sitting on a box in the living room for a day or two' cure process), but the gloss black parts needed a few more days to get from a palpably soft state to a ready to assemble state.
Curing of most paints can be accelerated by applying some heat. It doesn't take a lot; say about 100 deg F or so. Sun heating of a dark (say, gloss black) part will likely be warmer than that but seems to work fine (at least here in the Grey Northwet, aka Great Northwest, of the US). I've also used ovens, though not all will accurately run at low temperatures, and of course, don't use a microwave.
Good luck!
