Plaster Primer for Auro Paints

For bare lime plasters and bare clay plasters:

If you are painting with one of the standard wall emulsion paints such as the top selling Auro 555 Natural Wall Paint over bare lime or clay plaster, we advise you to paint a coat of Auro 301 plaster primer first.

For bare gypsum plasters

Use a mist coat, 10% water to 90% paint. (So if you are using Auro 555 as you main top coat, this is what you would also use, water thinned AS your mist coat / plaster primer)

When using Auro paints over bare gypsum plaster, we don't suggest using the Auro 301 actually! 301 plaster primer, which by its very name, should be recommended for bare plaster - but we tend to only recommend 301 for more absorbent plasters such as lime, and clay, not on a gypsum skin finish.  301, in our experience, doesn't always produce good results on a gypsum skin finish (the 301 tends to form slightly shiny film on the skim surface that the emulsion doesn't always stick well to, so we think a mist coat of paint is better on gypsum skin).

What are the Auro grip coats for?

The easiest, universal choice!

The Auro grip coats (Auro 505 Fine or Auro 506 granulated) are the most modern offering for plaster and primers, acting as a universal 'does everything'!

1) Mineral substrates like all plaster, clay, concrete, lime-sand bricks, and brickwork.
2) Gypsum plasterboard, cement fiber boards, and damp room boards.
3) Woodchip, vinyl wallpaper, and glass fibre fabrics.
4) Adhesive and wettable old coatings, including interior latex paints or lacquer coats

Summary
Grip coat 'fine' is the best/fail-safe wall primer, but then again 301 is the cheaper option (if that's a consideration!)

Plaster Primer for Graphenstone Paints

For painting over bare plaster with Grafclean Premium, use the plaster primer Nevada Ultra Primer, which is the recommended choice for Grafclean Premium matt and Grafclean Eggshell paints.

Plaster primer for Earthborn paints

If you have bare gypsum plaster walls and want to paint with an emulsion such as Earthborn Claypaint or Earthborn Lifestyle Paints, these are fine just to water thin and use as is. Once your plaster is perfectly and fully dry, you can mix your Earthborn paints 20% water to 80% paint which you can use as your mist coat / plaster primer. Once that has dried, paint top coat as normal.

Plaster Primer for Edward Bulmer Paints

If you are painting your bare plaster with Edward Bulmer paints, we also advise you to paint a coat of Auro 301 plaster primer first. Edward Bulmer paints are made with Auro base paints, so the Auro 301 plaster primer is perfectly compatible.

Read more: Do I even need primer on plaster?