Aside from the reduced working time (45min) and setting time (60min), Thistle Bonding 60 has a different smell and feel to it compared to other Thistle Undercoat plasters. The additional polymers and additives needed has given the plaster a unique texture to work with, often compared to older formulation products in how it feels to work with.
The reduced performance timescales does mean some changes to established site practice – for example Thistle Bonding 60 will set on the edges of tools if left too long before cleaning down. Also, we would strongly recommend using clean water and a clean bucket for mixing up in if you want to avoid inconsistent performance.
We would recommend the use of Thistle Bonding 60 on medium to lower suction backgrounds, in renovation and refurbishment applications.
All backgrounds need to be clean, sound and free from dust.
No pre-treatment is needed for;
- Medium-density blocks
- Engineering bricks
- Metal lathing
We would recommend pre-treatment with;
- Dense blocks
- Cast-in-situ & pre-cast concrete
- Painted/tiled surfaces
What about backgrounds not listed here?
We suggest users try a small test area before the larger job.
At the extreme high suction end of the range, suction control is needed, e.g. with Thistle Bond-It or PVA. Otherwise, crazing or shrinkage might be seen after application of the first coat. If this happens, stop and control the suction before carrying on.
When suction is high but not extreme, suction control may still be advisable sometimes, but is not usually necessary. For example a small high suction patch in an otherwise low suction wall, or a large area of high suction that must be finished in one operation. When suction is low or moderate, or if a smaller high suction area needs finishing, then pre-treatment is not needed.
Thistle Bonding 60 does what it says on the sack; set in 60 minutes. We recommend planning for a 45 minute working time, and waiting until 75 minutes before skim. Please note that like other Thistle Plasters you will see set-time performance changes based on the suction of the background and the method of control you apply.