Paint as Primer for plaster of Paris

[Jnunu]

Hi. Can I use a Matt black acrylic spray paint as a primer for a plaster of Paris base or do I need “proper” primer?

 

 Thanks 

[Black Knight]

No, you'll be painting forever. The paint will soak in.

I'd recommend a few coats thinned PVA glue to seal it. If you add Klear or similar to the PVA it becomes waterproof and quicker drying

[RJP]

It depends on the finish you want to achieve.  If it's a porous-looking surface you want, give it a try.  You might get away with a spray because the paint will be nearly dry when it hits the surface but that seems to leave a lot to chance.  For something smoother, or shinier, why not a basic primer?  In any case, a primer will ensure a uniform surface to work on.

 

I just finished renovating my house, including patching many small dings in plaster walls and sheets of new drywall whose joints had to be mudded.  In all cases, a coat of primer was necessary to achieve an invisible patch.  If I hadn't done that there would be obvious porous spots. No big problem to do it, just neatness and patience.

 

I found that a small tub of pre-mixed drywall joint compound worked out cheaper than hand-mixed spackling and was a lot more convenient.  Perhaps that's an option.  And craft stores sell various products for finishing cast plaster figurines and doodads.

[Jnunu]

Thanks all. Going to stop over thinking it and go for a black primer.