Tooling pushes sealant into full contact with both bond faces and the backer rod, drives out air pockets and forms the concave hourglass surface. It must be done before the sealant skins. A good tool line is smooth, slightly concave and clean at the edges. Untooled beads often look fine but have voids and poor contact at the sides.
You're gunning too far ahead, the tooling's dragging, it's already skinned on that run.
Tool in one continuous stroke where possible; stopping and restarting leaves laps and thin spots in the bead.
Also heard as
- tool
Related terms
Dry tooling
Tooling sealant without water, soap or solvent on the tool, as most manufacturers require.
Spoon
Caulker's word for a tooling tool, often an actual bent spoon or a spoon-shaped steel blade.
Skin time
How long after application a sealant forms a surface skin, which ends the window for tooling.
Hourglass profile
The ideal cross-section of a sealant joint: thick at both bond faces and thinner in the middle.