Do I need primer before Touprelith F?

[Merlin5]

Hi guys. A few questions if you don't mind. I've got maybe half a dozen small and very shallow patches (like about a millimetre depth) of bare masonry stone where I've taken off flaking paint. I've bought a box of Touprelith F filler. Can I spread the filler straight onto the masonry or do I need a primer? If no primer needed, do I need to first wet the areas to be filled? And I believe I've got to allow Touprelith F two to three days to cure before painting? And can I paint Sandtex masonry paint straight onto the Touprelith without a primer?

 

[opps]

I normally apply dilute SBR. Why? If the paint over the Touprelith F fails I do not need to worry about moisture ingress. It also helps to seal the sand stone. In many cases though it probably isn't necessary. If the surface is sound then a light mist of water may help.

Touprelith F is a great filler. I normally apply a dilute coat of masonry paint the next day if only using a thin coat of filler.

Try to over fill rather than under fill. If, for example, you fill a very large area, sand it back and notice that you need to apply more, when you sand back the second coat of filler, you will see a very slight ridge where the two meet. When sanding large areas, I apply a dilute coat, followed by a full fat coat and then apply more filler as required, taking care not to sand through the paint.

 

[Merlin5]

Thanks opps, good advice. Actually, yesterday and today I already went ahead and did my filling. I moistened the areas to be filled with an old toothbrush dipped in water. I made too much mixture the first time. I'm using a small 3 inch square plastic container and had only put about half an inch of water in it but realised it took a fair bit of powder to get a nice cement consistency paste. Today I used a lot less water and powder so that I only mixed up what I needed before it went off. Then made another a final small amount to finish off.

It's really nice to work with and easy to sand. I read somewhere that it mustn't be painted for 48 to 72 hours otherwise it can react with paint. It can effervesce I think it said. But obviously you've not had that issue. Yes, I slightly overfilled to make it proud of the cratered areas.
I used 120 grit and I also used a sponge sanding pad which is much finer though I don't know what grit it is.
This photo shows most of the areas I filled. Along the very top of the masonry as well.


Here are some horizontal cracks I filled. I opened the cracks a bit. Third photo shows after I sanded but looks like I didn't quite sand it enough and need to smooth it further.



This top corner shows exposed foam and was tricky to stuff filler into. But after sanding I've managed to shape it a little.

 

[opps]

looking good. Well done.