Just got off the phone with Ross from NZ Fibreglass Ltd.
He’s pretty amazing - and keen to give adivce.
Gelcoat probably isn’t what we’re after, but it sounds like he’s got multiple other products that would be ideal.
Apparently he’s supplied a lot of stuff to film/prop makers - started talking about coatings for movie weapons and fibreglass armour and the like.
The 1:1 silicone sounded like it’d be good (can be sprayed or painted).
They have gravity-fed spray guns for $95 that can handle latex (and things like silicone) - just hook up to a compressor.
I’m gong to go down there at some point (June at the earliest) and bring him one of my swords that I’ve made, plus one of the commercially purchased ones I have to show him the difference and get his thoughts.
Really, really good customer service on this guy’s part.