Once parts are brought into contact, the adhesive begins to skin over or cure. Closed assembly time is the window during which these mated parts can sit before they must be fully clamped or pressed to ensure a proper bond. If clamping is delayed beyond this limit, the adhesive may cure in a non-uniform state, leading to a weak joint or a thick bondline.
We need to get these panels into the press fast, the closed assembly time is only ten minutes.
Exceeding this time often results in a starved joint or pre-cured ridges that prevent the parts from seating properly.
Do not mix it up with
- Open time: Open time is how long the adhesive can sit exposed to air before mating, while closed assembly time is how long mated parts can sit before clamping.
Related terms
Open time
The longest gap allowed between applying adhesive and closing the joint while it can still wet the second part.
Pot life
How long a mixed batch of two-part adhesive stays usable before it thickens too much to apply.
Cure
The chemical reaction or physical change that turns a liquid adhesive into a solid that carries load.