PVA mixture where feathering

[shd1970]

I’m about to attempt my first skim directly onto some new plasterboard
I’ve always wanted to have a crack at it, so now is the time
The plasterboard butts up to some existing that is emulsioned, so I’m going to need to feather out the edges onto the existing.
I plan to use some scrim tape around the edges to stop the plaster cracking but I wondered if someone can confirm that I need to PVA the decorated wall for approximately 6 inches around the edges, and if so what PVA mixture I should use please ?

Thanks in advance

 

[Wayners]

Read on the PVA the ratio to mix but it's not critical. 4-1 I guess although most of the time I guessed and just added water to PVA then lashed on..
If you want the PVA to seal better you can use 2-1 but it's much thicker.
Give emulsion a coat of 4-1 and let it dry.
You could PVA in the joints and fill then let that set.
PVA the board and wall, give it 15mins then tape and skim.

Dispite what you hear feathering in edge will need sanding and filling. It's never invisible, I prefer to skim the entire wall to avoid problems.

 

[shd1970]

Thanks for the reply @Wayners
It’s just a patch up job as I’ve had to do some new piping for a new radiator so it’s fine for the edges not to be invisible although it’s not fine to do the whole wall as it’s 9 m long which would be a bit crazy for this, but I’d see what you’re saying (see photo)

It’s only a small area of 1000 x 400 so to go around the the existing for let’s say ~200mm is easy with a paint brush and I can be very accurate so from what you’re saying if I mix up some 4:1 and apply to the existing wall and give it a couple or 3 coats of that to seal it, it should be fine, yes ?

 

[Wayners]

Yeah. That's will do it.

Any residue of PVA is unlikely to effect emulsion when painted.
In all my years excess PVA hasn't caused any issues if that's what you are worried about