Prime with a Zinzer BIN. It is shellac-based rather than latex. It sands
well. An oil-based primer would probably work well too, but it would require
more time to cure before sanding.

-steve



"sploo" wrote in message
news
Hi all,

I'm trying to achieve a smooth painted finish on MDF.

I have a project where I'm cutting rings out of 3/4" sheets (each ring
has a 17" external, 15" internal diameter). The rings are then glued
together to create a tube.

My previous experience of finishing MDF was priming (with a brush) a set
of loudspeakers, sanding down and then spraying them with tins of paint.

I had huge problems with the primer (International MDF Primer) as it
never seemed to dry properly - attempting to sand it would result in
dragging off tiny rolls of primer and it clogged the paper. I even
bought a second batch, thinking the the first was contaminated, and left
the piece to dry for a week. It still wouldn't sand.

As I don't have a HVLP spray setup, could anyone recommended a primer
that I can paint/roll onto the outside of these rings, that will sand
well, so I can produce a perfectly smooth finish that I can spray paint?
I'm in the UK BTW.

Many thanks.