Removing tile primer

Hello dear community,

we have a few stains from the primer ([Kaliwasserglas]) on the tiles. They cannot be removed with a scraper. Is there any product that works? I have already tried all cleaners. Does paint stripper work?

I would be very grateful for any help!

Best regards

I join the question with interest. I wasn’t paying attention during the renovation and primer got on the window panes and the sill. So far, it cannot be removed by anything.

Recently tried to clean an old spray bottle filled with dried-up primer. Soaked everything in water... after a while (overnight) it became kind of rubbery and you could rub it off. The idea would be: Maybe you can stick a damp kitchen towel/paper towel to the window overnight and the stuff will soften and can be rubbed off.

...that’s not going to work. Water glass/silicic acid forms a crystalline bond with the mineral substrate (silicification). It becomes one with the substrate. I use it for mural painting with mineral pigments on a mineral substrate. If you accidentally mix too much, it hardens by the next day because the formation of crystals has begun. Silicification takes 2-3 weeks to complete in summer weather.

You have to come to terms with that; it won’t come off anymore.

Many primers have an acrylic base, which you can remove more easily. It’s not a pleasure either, and if the substrate was porous, you won’t be able to reach everything. Acrylic is easily destroyed with acetone; I have already obtained it in pure form at the pharmacy. Acrylic is not completely waterproof; it absorbs a small percentage of water and then becomes milky and loses its strength as long as it contains water.

Best regards
Gabriele