I wonder if anyone can help. I have quite a large wll to finnish plaster on my own. Does anyone out there know how to stop the plaster setting so quicky, is there anything I can add to it? I have heard that Lime Putty works, but not sure what the finish will be like or how long it gives you. Would like to hear some thoughts....... I am jst skimming with finnish plaster.
Does anyone know how to stop plaster setting so quickly
- Thread starter Building66
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And what do you call too quickly?
Is it board or multi finish, you are using?
What is the base coat you applying to, is still damp or dry?
If the plaster is going off, is it out of date?
Also plan your areas to give best usage and time allowances.
Is it board or multi finish, you are using?
What is the base coat you applying to, is still damp or dry?
If the plaster is going off, is it out of date?
Also plan your areas to give best usage and time allowances.
If you are skimming over new board no problem, if its over existing sound plaster, give it a coat of pva day before, then another coat prior to skimming, wait until tacky then get your first coat on, you should have enough time to flatten out, wash you kit ready for second coat.
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I am plastering an area of about 2.5m high and 10m long with no breaks. Using multi finish. Going straight over the top of existing plaster ( has been painted, but have keyed it up). I could do it in two halves, but i was wondering if there was anything out there that would delay the existing setting time of multi finish, a bit like plastisiser for mortar.
If you cant manage it on your own, get another spread to give you a hand for a couple of hours.
This is probably the best idea. Without the PVA the existing plaster will suck the moisture out. Putting the pva on will provide a seal between the two surfaces retaining the water in your new coat for longer.
Plaster is chemical cure & although we’ve hade several threads/theories about delaying cure in the past (including ****ing in it), I know of nothing that works.
You can kill the suction by applying an initial sealer coat of PVA the day before (but never plaster over dry PVA). Applying the regulation two coats will give more time as the second coat will stay workable longer. Make sure conditions are good, no excessive heat or draughts. Ensure the plaster is in date & has been well stored, not in a builder’s merchants grotty damp tin shed, especially this time of year; I always get mine from BNQ. Only fresh water & keep your tools very clean, particularly between mixes.
Even so, your never going to get more than 1 ½ hours start to finish which means you must aim to get it all up there in around 40 minutes if your going to have enough time to flatten off, trowel up & polish before it all goes off on you. I work alone & usually plan my day around 4 two hour sessions allowing time to clean up, have a breather & mix up the next batch. Don’t be tempted to use loads of water; it won't bring it back sucesfully & you’ll probably end up with a white mush sitting on the surface in hollows all over the wall.
If your speed isn’t up to 25 sq/m in one hit, you’d do better to break the wall into two sections using a thin coat stop bead; plaster up to the edge, not over the mesh! Remove the bead just as the plaster has set & plaster the second half of the wall with a new mix immediately after you’ve finished the first. Done well you won’t see the join & it shouldn’t crack as long as you follow on with the second half straight away; also stick some reinforcing tape to the wall under the join line. I’ve used this trick a few times on 4 ½ metre high conservatory gable walls, large ceilings & occasionally when it’s been necessary to leave a part of a wall unplastered due to further building work.
You can kill the suction by applying an initial sealer coat of PVA the day before (but never plaster over dry PVA). Applying the regulation two coats will give more time as the second coat will stay workable longer. Make sure conditions are good, no excessive heat or draughts. Ensure the plaster is in date & has been well stored, not in a builder’s merchants grotty damp tin shed, especially this time of year; I always get mine from BNQ. Only fresh water & keep your tools very clean, particularly between mixes.
Even so, your never going to get more than 1 ½ hours start to finish which means you must aim to get it all up there in around 40 minutes if your going to have enough time to flatten off, trowel up & polish before it all goes off on you. I work alone & usually plan my day around 4 two hour sessions allowing time to clean up, have a breather & mix up the next batch. Don’t be tempted to use loads of water; it won't bring it back sucesfully & you’ll probably end up with a white mush sitting on the surface in hollows all over the wall.
If your speed isn’t up to 25 sq/m in one hit, you’d do better to break the wall into two sections using a thin coat stop bead; plaster up to the edge, not over the mesh! Remove the bead just as the plaster has set & plaster the second half of the wall with a new mix immediately after you’ve finished the first. Done well you won’t see the join & it shouldn’t crack as long as you follow on with the second half straight away; also stick some reinforcing tape to the wall under the join line. I’ve used this trick a few times on 4 ½ metre high conservatory gable walls, large ceilings & occasionally when it’s been necessary to leave a part of a wall unplastered due to further building work.
I Guess I will be a lot thinner by Monday .Cheers for the help. I may try the lime putty on a small area and let you know how it goes.
As mention in previous posts, PVA prime the walls.
And three shredded wheat
And three shredded wheat
Cream of tartar you can usually buy it from a local shop (England)...............i used to work with a brilliant plasterer that used to use it in the summer..........I think he used to put a half a teaspoon in per mix.......hope this helps 
It would have deffo set by now.Cream of tartar you can usually buy it from a local shop (England)...............i used to work with a brilliant plasterer that used to use it in the summer..........I think he used to put a half a teaspoon in per mix.......hope this helps
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