Plaster skim flaking

[sueonmull]

We have recently plaster boarded a room and had a plasterer in to put on two coats of multi-finish plaster. The room is warm and ventilated and now, after nearly a week, we want to finish off putting in the back boxes for the electrics. Having a problem getting a neat edge using a dry wall saw as the the top coat of plaster is chipping/flaking cleanly off the first coat. I’m hoping there's a better technique and not that there’s a problem with the plastering. Any advice would be appreciated please. Thanks.

 

[Micilin]

Any chance of pic ?

Can you get a knife in between and seperate in flakes easily or is it just a bit as you cut out for the boxes?

 

[sueonmull]

Thanks Micilin, on the small bits we've tried you can get a knife and separate the layers.

 

[Burnerman]

Here's me wondering (as the worlds worst plasterer, bar none ) that maybe the base coat wasn't dry before the top skim was applied?
Lets here what the others say.....
(J'adore Mull, moi).
John

 

[sueonmull]

I think the second coat would have been put on the same day, he seemed to go round and do the room in sections, certainly the ceiling was all done and finished on the first day.

 

[loply]

Here's me wondering (as the worlds worst plasterer, bar none ) that maybe the base coat wasn't dry before the top skim was applied?
Lets here what the others say.....
(J'adore Mull, moi).
John

Wouldn't it be the opposite? The second coat applied after the first one has hardened too much, so they didn't become homogenous...?

 

[sueonmull]

We have managed to put in all the back boxes and eventually devised a method that worked for us - we cut through the plaster with a stanley knife at a slight angle so that when the plasterboard saw was used it didn't have to rub against the edge of the plaster. As usual only got the knack when we'd nearly finished! Anyway all done now and thanks to all for your help. Wallpapering next