DIYbanter - One Strike Filler

On Thursday, 16 May 2019 15:55:20 UTC+1, Andrew wrote:
On 14/05/2019 17:54, Jim K.. wrote:
Andrew Wrote in message:
On 12/05/2019 11:48, tabbypurr wrote:
On Saturday, 11 May 2019 20:43:32 UTC+1, Andrew wrote:
On 09/05/2019 19:34, alan_m wrote:
On 09/05/2019 17:51, TMH wrote:
On 08/05/2019 18:10, Andrew wrote:

Keep a bag of out-of-date Wickes fine surface plaster and use
that. It sets within minutes and unlike gypsum plaster it can
be scraped flat (with a steel ruler) and also sanded.

I'll check that out. Does it have to be out of date?

I presume it's like very out of date gyssum plaster that sets hard
within 5 to 10 minutes of mixing. When renovating my house 30+ years ago
I used some out of date plaster as a grip fix adhesive for installing
electrical back boxes in rather irregular holes in the walls. Being
quick set a few blobs of old plaster would hold the boxes firmly in
position with 5 minutes with enough time to make sure that they were
horizontal and flush with the rest of the wall. Fresh plaster was used
for making good afterwards. I used cheap disposable plastic cups to mix
enough for one back box at a time.

Out-of-date gypsum plaster goes off and sets too hard to allow any
remedial work, short of messay power tools. The Wickes fine surface
filler does allow some 'shaping' with a decent scraper like a steel
ruler after it has set but before dry (unless they have changed the
formulation since I last did so, a few years ago).

Don't fill so badly that you need to remedy it. Why do people do that?

NT

Because the whole point of using some 'old' plaster/fller is because
it will set quite quickly (sometimes a necessity), but on occasions
sets a bit too quickly while trying to get a nice flat smooth
finish.

If time was not an issue then use fresh stuff.

Hang on, you sound like someone who's actually done it? Or are you
another "## merchant" to keep an eye on?
;-)

DIY, I used it a lot a few year back as I decorated each room in turn.
Back in 2009 it came in 5 kg packs, in tough plastic bags, which
is fairly convenient, less wastage.

My 1976 house has very crumbly sand/cement basecoat plaster with a wafer
thin skim of grey gypsum, needing a lot of patching.

Drilling holes would typically result in a hole about an inch across
as the plaster just disintegrated !. I soon noticed that particular type
of filler tended to set fairly quickly once it was 'old' so handy for
fixing these holes or for example, like when changing a single socket to
a double, needing a small amount of filler that set quickly but could
(if necessary) still be mechanically smoothed.

Aye. FWIW I long ago did a cheap fix to avoid replastering when it was all crumbly. Dilute PVA _very_ weak & slosh lots onto the wall in one go, as much as it'll absorb. Soak it. When it eventually dries out the result was glued together enough to survive another 20 years before needing any work. It's not as strong as new plaster but quite good enough. The key is getting good penetration, so it needs to be very weak & saturated as near as you can.. People have also used multiple coats of lime water this way.

NT