Greetings!

My E-100 Project is currently going through the phase where I'm detailing the surface including such tasks like adding weld lines using Tamiya Epoxy Putty ( Quick Type ).
This will basically be a first use for me but from what I've learned while watching a bunch of Uncle Night Shift YouTube Videos it appears that water is the key to preventing it from sticking to surfaces I do not want it to stick to while I'm working with it.

My guess though is this technique is having some short time limitations? 🤔

Reason I'm asking is because of the removable Panels on my E-100 that would normally have a welding seam going all around their perimeter like with the in the below picture Turret Top Armor ( loosely placed on top of Turret ) and Chassis Top Armor ( recessed flush in position ) most likely requiring a substantial amount of time to complete the Weld Seam all around probably negating the repellant behaviour of the water?:

Both Armor Panels have a Stepped Boarder that will create about a 1mm Gap around them with their neighbouring Front / Rear / Side Armor Panels.
The idea is to fill that gap with the Putty, sculpt it into a Weld Seam all while it only sticks to the stepped Top Armor portion but not the neighbouring Armor Panels.

Any suggestions about if and how this could be achieved? 🤨