Filling mdf skirting

[Screech20]

Hey guys,

I've just skirted a room with primed mdf skirting. I've had to drill and screw as the walls are so out!

I've got a 2 part filler for the screw holes and mitre joints, and caulk for the scribed corners.

Question is, does the filler go best onto the bare mdf (where countersunk) or should I spot prime the holes then fill?

Cheers

 

[Burnerman]

In with the filler first, sand then prime over the top. Job done!
John

 

[Screech20]

Great, thanks john. Guess what I've been doing today

Oh and when I said spot prime, didn't quite think I need this much lol



Cheers

 

[Screech20]

PROBLEM!

I've just cracked open the primer and started priming the door frame after days of prep, ran my hand over the skirting thinking I need to get that done too, and all the filler has sunk!

I thought this stuff was meant to be crank and shrink free!

Any ideas why this has done that and where to go from here!

I was really proud of all this when I done it, but now if I paint it it will standout like a sore thumb!

Cheers