Can you use a grenade to make foam walls?
Yes, iron foam grenades
Do remember that fluorosurfactant + water creates foams for chemicals that you adds along side in the grenade payload
While foam agent (not flurosurfactant) + fluoro acid + iron with the ratio of 1/1/3, can creat an area of foam turning into iron walls
Chemical foam grenades with iron will only add chemical iron inside people or animals who got caught inside the foam
And foam agent with iron will trap people inside and crushing them + suffocating people inside the iron walls if they didnt escape in time
If you want to make a wall or intentionally shaped walls, you can try “molding” by creating walls that hollows out a shape you want your foam to cover and shape. (It looked very ugly, I tried it)
Iron foam grenades are rarely used for engineering or building uses due to how bad it is for repairing breaches since it blocks more passages that holes it patches
Because of how iron foams can denies entry and exits in very big areas with minimal time and effort plus slowly killing anyone trapped inside the foam, its mostly used by antags to either bogging down security or escaping mobs