Stephen wrote:
Hello,

As you may have read in my other post, I have been rollering a
ceiling. The ceiling was plastered and allowed to dry and then I
painted it with Blue Hawk plaster sealer from B&Q and allowed that to
dry. When I rollered the ceiling 99% went on fine but in one or two
patches I got some tiny blisters.

I made the mistake of scraping the blisters but this made them worse
because they kept blistering at the edges so I scarped back more and
got bigger and bigger bald patches!

I left some blisters alone and to my surprise, when the paint dried,
they disappeared completely.

What caused the blisters and how can I avoid them in the future? Was
the plaster not sealed adequately; I've never seen them on any other
ceiling I have painted.

I have over painted the craters that I scraped out and they are
staring to look more hidden but they can still be seen when the light
hits them from a certain direction. What's the best way to remove
these: some filler?

Thanks.

I've had this problem with gel type emulsions. Some are thick enough to
stand your brush in.
I think a fine surface filler applied with a plasterers trowel is
probably your best bet, trying not to leave any excess that would need
sanding.