Quick Answer

Apply densifier after the coarse metal bond grinding (around 50-100# equivalent surface) and before the fine resin steps. Let it cure fully before polishing. Densifying too early seals in contaminants; densifying too late means the fine grits polish a soft, porous surface that will not shine.

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Why Timing Matters

The densifier reacts with free lime in the concrete to harden the paste. If the surface is still dirty or coated, the reaction cannot reach the lime. If you wait until the floor is already polished, the fine grits have cut a smooth skin that the densifier cannot penetrate deeply.

The Standard Window

• After coarse grinding (surface open and clean)
• Before the 200#-400# resin steps
• On a vacuumed, dry floor

Curing Time

Most lithium densifiers need 1-4 hours to react; some systems recommend overnight. Follow the label. Polishing before cure locks in soft pockets that appear as dull spots later.

Common Mistakes

• Densifying over a coated or dirty floor
• Densifying after the final polish steps
• Polishing before full cure
• Skipping the densifier entirely to save time

Frequently Asked Questions

Q: Can I apply a second coat?

A>Yes, a second light coat after the mid-polish steps is common on porous floors.

Q: What if I already polished without densifying?

A>You can densify and burnish again; the gain is smaller but still real.

Q: Sodium or lithium densifier?

A>Lithium reacts faster and polishes brighter; sodium is cheaper and works on porous slabs.

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Conclusion

Densify between grinding and polishing, on a clean floor, and respect the cure time. It is the step that turns a hard floor into a glossy one.