Bona Products yet again proven to be the most economical!
Bona has been telling its customers for 10 years that the use of a primer is not usually necessary under a good silane adhesive like Bona R850. However, some competitor products now require that a primer is used under certain silan-based adhesives even on normal cement and anhydrite.
When introducing the R860 and R850 10 years ago, Bona sparked a revolution in the wooden floor adhesives market. In particular, Bona R850 quickly replaced solvent adhesives for many floor layers due to its quick and easy handling. Whereas a primer always had to be used along with solvent-based adhesives in order to get good bonding, R850 could be applied directly to the substrate.
“I then questioned how important priming is when using silan-based adhesives” says Dr. Thomas Brokamp, at that time responsible for the development of adhesives, “all of our tests showed that our silan-based adhesives binded dust very well and that a primer didn’t improve the bonding strength. The use of primers has therefore been written only in exceptional cases, but not as a rule on good cement or anhydrite.”
While competitors also used this assessment for many years the situation is different today. For some months now a number of competitors have started to recommend the regular use of primers on cement and calcium sulphate based screeds under certain silan-based adhesives. There is now some confusion in the market and the Bona technical team is being confronted with an increased amount of enquiries.
What you need to know:
- Under R850, R848, R844, R860 and R870 on cement and calcium sulphate based screeds no primer is usually needed.
- In order to bind dust and work cleanly, absorbent and dusty substrates can be treated with the dispersion primer D501.
- On non-dry screeds it can be useful to use a moisture barrier such as R580, R540 or R410.
- R540 or R410 can also be used to solidify the screed surface.
Priming costs money. Not using a primer of course saves you from the work and the waiting time between the application of the primer and the adhesive, which can be up to 24 hours depending on the system. And don’t forget the material costs of the primer itself.
To summarize: gluing with Bona is quicker, more economical and safer!