Frequently Asked Questions

What is the difference between Thioflex 600 GG (gun-grade) and Thioflex 600 PG (pouring grade)?

The difference is in the consistency (viscosity) of the mixed sealant and the application method. Thioflex 600 PG is a self-levelling low-viscosity formulation designed for horizontal floor joints — it is poured from a disposable spout or container directly into the joint from above, and self-levels to fill the joint width and depth by gravity. Thioflex 600 GG is a thixotropic non-slump formulation designed for joints in any orientation — it is applied using a caulking gun and holds its position in the joint without slumping, allowing it to be used for vertical, inclined, and overhead joints. The underlying polysulphide chemistry, curing mechanism, and cured-state performance of both grades are very similar.

How should the joint be prepared before applying Thioflex 600 GG?

Joint preparation is critical for adhesion and long-term sealant performance. The joint faces must be dry, sound, and free of all dust, laitance, oil, grease, curing compounds, old sealant, and primer residue. Mechanical preparation (grinding or wire brushing) of the joint faces is recommended. A closed-cell polyethylene foam backer rod must be installed in the base of the joint to control the depth of sealant and ensure the correct depth-to-width ratio (typically 1:2) — too deep a sealant body increases stress in the sealant during movement. A Fosroc polysulphide primer (Thioflex primer) appropriate to the substrate (concrete, metal, or glass) must be applied to the joint faces and allowed to become tacky before the sealant is applied. Application without proper priming will result in adhesion failure at the joint face.

How long does Thioflex 600 GG take to cure and when can the joint be put in service?

Thioflex 600 GG cures by a chemical cross-linking reaction between the base compound and the activator. At 25 degrees C, the mixed sealant achieves a surface skin (tack-free) within 4 to 8 hours and full cure within 5 to 7 days. At lower temperatures, curing is slower. In Indian summer conditions (above 35 degrees C), curing is accelerated and pot life (working time after mixing) is reduced — it is important to mix only the quantity that can be applied within the pot life and to keep the unmixed materials cool before use. The joint should be protected from traffic loading and movement until the sealant has reached adequate cure — typically at least 48 hours at 25 degrees C before light foot traffic and 7 days before heavy traffic or water exposure.