Is KERDI-FIX actually waterproof?

Yes. Schluter rates it as a waterproof sealing and bonding compound, and it is the product specified for waterproofing pipe and valve protrusions in the KERDI shower system.

How long does KERDI-FIX take to cure?

It skins over in about 10 minutes. Full cure takes roughly 24 hours for every 3 mm of applied thickness, so thick beads need longer.

Can I use it instead of silicone on metal or glass?

It bonds well to metal, glass, stone, concrete, wood and many plastics, and it is UV- and weather-resistant. For joints that need a flexible, paintable seal it is a reasonable choice, but it is not a structural adhesive.

How much does one 290 ml cartridge cover?

Coverage depends on bead size. A thin bead along KERDI-BAND goes a long way, but sealing several pipe protrusions and corners can use a cartridge quickly, so buy spares for a full shower.

Is it only for Schluter products?

No. It is designed around KERDI membrane, KERDI-BAND and BARA balcony profiles, but it also works as a general sealant and joint filler on the materials listed above.

When is the best time to buy it?

The best new price on record is $29.74 at Home Depot as of November 4, 2026, with 4 stores listing it new. Compare those listings before a large order, since cartridge count drives the total.