Activators and primers
Surface preparation that decides whether the bead holds: K-901 activator, K-801 primer.
K-901
Activator
Surface activator for glass, metal, ceramic and painted substrates.
K-801
Primer
Black primer that builds the adhesion film under PU and STP sealants.
Compare the models
Typical values from the catalogue; the batch record carries the measured result.
Choosing one
Buy the preparation with the adhesive, not after it. K-901 cleans and prepares the frit; K-801 builds an adhesion film where a primerless grade cannot bond. Both ship in 5 ml to 1 L cans with a six-month unopened shelf life, so order against a production date rather than holding stock.
Where it goes wrong
Most "primerless" failures are contamination, not a missing primer. Silicone residue from a previous bead, mould release on a trim, or handling oil on a frit will defeat any activator. The primer is the fallback, not the first answer.
Five millilitres is a sample and one litre is a production pack. The shelf-life clock starts at filling, not at opening, so a can without a production date is a can you cannot plan a line around.
Decision table
| If | Then | Because |
|---|---|---|
| New frit, cleaned and dry | K-901 only | the activator removes handling oil |
| Unknown substrate or a previous silicone repair | K-901 plus K-801 | the primer builds the adhesion film |
| Bare plastic trim | K-801 after a coupon test | some plastics need a specific primer |
| Stock has no production date | reorder | six months unopened shelf life, not indefinite |
Read before you specify
Other families
- Automotive glass bonding — Windscreen, side and rear glass adhesives — 310 ml cartridges, sausages and 200 L barrels.
- Body and sheet metal — Seam sealers for body panels, doors and container joints — sandable, paintable, four colours.
- Construction joints — Concrete, tunnel and drainage sealants — 550–615% elongation, elastic recovery up to 80%.
- Industrial and STP — Silyl-terminated polymer sealant for metal, plastic and glass — primerless and paintable.
- Wood and glulam — One-component PUR for engineered timber, glulam beams and sandwich panels.