The Tool Gun

Weld, rope, camera, no-collide: the tool weapon, and Elipcee tools.

Picking a tool

Equip the Tool Gun (often slot 1 or 2, or Q → Tools). At the bottom or in Q, pick Weld, Rope, Hydraulic, Balloon, Camera, Remover, No Collide, Stacker if it is there, etc.

Left-click applies, right-click is often the reverse, R reloads or restarts depending on the tool.

The most useful Sandbox tools

Weld
Welds two props. First click on A, second on B.
No Collide
Two objects pass through each other. Useful for doors or details.
Rope / Hydraulic
Physical links. Machines start here.
Remover
Deletes a prop (yours, in principle).
Camera
Place a camera, then F11 or the tool to look through it.
Colour / Material
Color and texture of a prop.
Stacker
Duplicates a prop in one direction, for straight walls.

Elipcee tools (admin)

In the Elipcee Tool Gun category: capture points, PvE zones, info boards, leaderboard screens, quest boards. Staff tools. A normal player does not need them to play.