Buttering both faces makes sure each surface gets wetted by fresh adhesive instead of relying on squeeze to carry it across. It is common with thick pastes, porous parts, structural core bonding and when one surface is hard to wet. Contact cements must be applied this way. The term comes from spreading butter with a knife and is shared with tile setters and masons.
Butter both faces on the core splice, a single bead won't wet that foam properly.
Also heard as
- butter
- double spread
- back-buttering
Related terms
Contact cement
An adhesive applied to both surfaces and left to dry before they are pressed together for an instant bond.
Wetting
How well a liquid adhesive spreads over and makes intimate contact with a surface.
Starved joint
A joint left short of adhesive, with bare patches or voids where the glue soaked in, squeezed out or never reached.
Squeeze-out
The excess adhesive that oozes out along the joint edges at clamp-up, read as proof the joint is full.