A finish plaster only earns its keep if it sets evenly and closes down cleanly. For supervisors, ThistlePro DuraFinish needs particular attention because it is specified for harder-wearing, high-traffic areas and must be applied at 2mm to achieve its stated performance .
Start with the Right Mix Discipline
Treat consistency as a quality-control item, not a plasterer’s preference. Thistle plasters should be added to clean water using clean mixing equipment; contamination from previous mixes can affect setting time and strength . On site, that means checking buckets, whisk paddles, spot boards and water before the first gauge.
Use a slow-speed, high-torque whisk and stop once lumps are dispersed and the plaster has reached a smooth, workable consistency. Over-mixing is a common cause of trouble: it can affect setting times, reduce workability and make it harder to achieve a flat finish .
Reading the Mix on the Wall
For DuraFinish, supervisors should look for a mix that spreads firmly without slumping, tears or excessive drag. Too wet, and the plaster may hang open, slide on angles and delay trowelling. Too stiff, and the team will fight the wall, risking fat edges, poor closing-in and uneven suction marks.
Common mistake: adding extra water late to “bring it back”. Corrective action: reject the gauge once it has started to tighten; do not re-temper. Common mistake: using a dirty bucket to save time. Corrective action: wash out immediately after each mix, as small amounts of set material can accelerate fresh finish plaster .
Set Time Expectations
ThistlePro DuraFinish has a minimum setting time of 105 minutes, longer than standard Thistle MultiFinish at 90 minutes . Build this into bay sizes, labour allocation and inspection timing. If the set is racing, check for contamination, warm backgrounds or poor suction control. If it is dragging, check cold conditions and over-wet mixes.
Safety and Site Conditions
Maintain ambient and background temperatures above 5°C until DuraFinish is fully dry . Keep walkways clear around mixing stations, control trailing leads from whisks, and wear eye protection and suitable respiratory protection when handling dry plaster. Wet plaster is alkaline, so gloves and prompt washing help reduce skin irritation.
