Decorators Caulk V Polyfilla

[Prudie]

Just to expand my education when do you use caulk rather than filler? I filled some small screw holes in plaster with decorator's caulk (because it was all I could find in the cupboard) but it was useless and have had to remove it all. It won't sand and comes off in curly rubbery bits (and now successfully job done with regular polyfilla) however now I'm wondering why we even had it, what is caulk used for?

[The Builder]

You're right with filler for your screw-holes Prudie.
Caulk is flexible. Used mainly for small cracks which need to be able to move around a bit through either movement or expansion/contraction.

Filler= solid
Caulk = flexible.

[Buenchico]

An informative thread:
http://www.ultimatehandyman.co.uk/forum1/viewtopic.php?t=70561

[Old_Geezer]

I agree that caulk doesn't sand down easily as I found out after I did my usual trick of not pretending to be an expert and overfilling. It will cut with application of a workknife blade though, but that's tough on the fingers and you have to be careful not to pull it back out of the wall.

For screw holes you need filler.

[royfromaus]

Caulk for skirting boards because there will be movement and caulk is flexible.
Filler for plaster because you can sand it down.

[royfromaus]

If you find a filler that sands down easy, remember what it is called. There's some fillers out there that become harder than diamond and the only thing that sands down is the original plaster.

[Prudie]

Thank you all, I have learnt something today :-)

[theshedman]

If you put caulk where wood meets plaster ie skirtings, door frames etc and where plaster meets plaster like at the top of walls where they meet ceilings and use filler for most other things you wont go far wrong.