So, the adhesion primer test results are in, and they are very surprising to say the least. First, I will explain what we did and how we did it. We painted samples of Tikkuril Otex, Tikkurila Otex Akva, Caparol Haftprimer, Johnstone’s Advanced Multi Surface Primer and Teknos Aqua Futura Primer on 5 different samples.
The Adhesion Primer Test
We had bare wood, previously painted with oil-based gloss, ceramic tiles, steel and galvanised steel. They all had 1 coat of the respective adhesion primer and were left for 10 days. I also had enough of the previously painted wood, steel and galvanised steel samples to do a test on these with Zinsser Cover Stain and Zinsser Allcoat Primer and Finish.
I then gently scored a small cross on every sample with a blade and put a piece of cellotaph over the cross, stuck it firmly down and left it 10 seconds before removing it. As you can see from the photos at the bottom of this blog, some of the primers adhered better than others. We repeated this process 3 times in different spots on the samples to get a clearer picture of which were the best performing adhesion primers.
My lad Matt and I checked all the samples and the cellotaph and he marked them in the order of best to worst, without knowing which was which because the names were written on the back of the tiles.
Of the 3 samples we did using Zinsser products; they all performed worst over previously painted wood.
Coverstain was second and Allcoat was last for steel.
Coverstain was last and Allcoat was 5th for galvanised steel.
So, they weren’t very impressive. The list for the others in order of best to worst is as follows.
Bare Wood
- Johnstone’s Advanced Multi Surface Primer
- Otex Akva / Teknos ( too close to call)
- Haftprimer
- Otex solvent
Painted Wood
- Johnstone’s Advanced Multi Surface Primer
- Teknos
- Haftprimer / Otex / Otex Akva
Ceramic Tiles
- Johnstone’s Advanced Multi Surface Primer
- Haftprimer / Teknos
- Otex Akva
- Otex
Steel
- Haftprimer
- Zinsser Coverstain
- Johnstone’s Advanced Multi Surface Primer
- Teknos /Otex /Otex Akva
Galvanised Steel
- Johnstone’s Advanced Multi Surface Primer
- Haftprimer
- Otex Akva
- Teknos
- Otex
Johnstone’s Advanced Multi Surface Primer was the best performing primer followed by Haftprimer, Teknos Aqua Futura, Otex Akva and, unbelievably Otex solvent based at the bottom. The only conclusion I can draw from this is that the solvent-based adhesion primers cure quicker originally, but the water based primers are better once cured.
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