Plaster retarders

[Georgeone]

Hello all!

I am having difficulties to make a good plaster mix.
What I do, I mix 1 bucket ( 1 bag 25 kg plaster and some water ) make a nice creamy mud put it on the spot board and I just try to put it on the wall as quick as I can, by the time I run out of mud my help is ready with the second bucket of mud for the second coat, the problem is sometimes first coat sets too quick or it could be even worst if I am on my own and I have to wash the bucket , drill and whisk, and finally to start putting second coat, so by then the first coat on the wall is so hard so I have to give it a good trowel and flating before I can put a second coat meanwhile the mud is just started to set so you can imagine how hard is to work with it.

I think if I use some retarders or I dunno, i might be doing something wrong , anyway I was a chef for 10 years before I started to do plastering for a living so my experience is just a few months patching and a few small walls and ceiling done by my self.

Any bits of advice will be appreciated

P.S. I do apologize for my bad English, it's my 3 language

 

[JerryD]

You're possibly using the wrong plaster type for the background you're plastering?

High suction backgrounds need Hardwall or Browning whereas low suction backgrounds need something like Bonding. (Top coat is the same regardless of the background, try Multi Finish)

If you're using Bonding on a high suction background it will shrink and craze.

Some blocks need wetting prior to plastering, this stops the immediate suction and gives you more time.

Use clean (drinking quality) water for mixing, dirty water speeds the set time.

Turn off all heating in the building at least 24 hours prior to plastering.

Perhaps you are just too slow? My plasterer uses a bucket of plaster in about 60 seconds, his labourer is mixing full pelt!

 

[wreckedit]

Hi,
I want to have a go at plastering sometime and bought some for the great day but my mate said that plaster even unopened lasts only a short time before it goes off. That is it sets more quickly. I have no idea if this is true so would like to know if this is true or an old DIY'ers tale. It might help!!!!!

 

[legs-akimbo]

.Quite so! if you buy it then use it, keep it longer than a month and its past its best and will indeed set faster. A splash of regular washing up liquid in a skim mix acts as a retarder and gives a longer working time, have not tried this myself but picked it up from another plasterer on a forum.

 

[chappers]

could the salts in the washing up liquid not cause problems as in using it as plasticiser in mortar.

 

[-dj-]

don't know about fairy liquid but i have heard that normal mortar plasticiser will slow it down, also peeing in the water will slow it. i personally don't use anything, i've never had call to, remember gypsum don't reccomend it but that doesn't mean to say they don't work.

dj.

 

[JPL_Plastering]

If you are plastering on a dry background then always wet it down to slow drying time and improve workability, also if your are skimming on to old masonry then always apply a coat of watered down PVA and if you are really slow let that go tacky and give it another coat of slightly stronger PVA that will give you plenty of time to get the finish on also make sure your bucket is absolutely spotless for the next mix otherwise your next mix will have the same drying time as the first! Its sounds weird I know but its true I have been plastering for 11 Years now
The other thing is that you will get quicker it just takes time like anything but dont try to take on a wall that is too big for you try to break it up in some way and dont worry too much how your 1st coat of finish looks just get it on quick as you can you can always do much more with it when it us just starting to go. Then you can clean your bucket and tools get yourself a fresh water bucket then mix a smaller fresh mix of finish say about 20% of the original in size and just "lay the plaster down" with this new mix which basically involves flattening the first coat down more or less putting it on and pulling off the excess.
I remember my old gaffer Don used to say to me when I was younger "Wax on Wax off" just like the Karate Kid
Hope this helps you or someone else.
Cheers
Paul

 

[MANDATE]

Hi JPL! Does your advice regarding wetting down or applying watered down PVA also apply to the skimming of plasterboard.

 

[jbonding]

no you dont have to wet or pva plasterboards before skimming unless your skimming moisture resistance boards which are mainly used in shower rooms and bathrooms, when i mix i make sure ive got two skimming buckets with enough water for two mixes and a cleaning out bucket, mix your first mix, put it on your spot board making sure your spot board has been soaked for a while or this will send the plaster off quicker. clean your bucket and whisk using a sweeping brush head and empty back into cleaning out bucket now your set up for your next mix.

 

[JPL_Plastering]

Pretty much as he says mate you dont need to PVA Plasterboard apart from aquapanels but i dont even PVA them sometimes
Also another thing I meant to say in my original post was for you ppl who are struggling to get a mix used before its gone off I would suggest not using a spot board at all and investing in a bucket trowel about £5 or even get a brickies trowel and cut it down square, that way you can get your plaster as you need it out of the bucket. This will let it hang on a bit longer as a spotboard especially a wooden one (even soaked) will still take the moisture out of your mix quicker. Another thing to remember is not to have doors or windows open with a breeze blowing directly on to your wall as that will also dry it quick. Thats about all I can think of to help begginers but there really is no sustitute for timed experience.
Cheers
Hope this helps

 

[-dj-]

Pretty much as he says mate you dont need to PVA Plasterboard apart from aquapanels but i dont even PVA them sometimes
Also another thing I meant to say in my original post was for you ppl who are struggling to get a mix used before its gone off I would suggest not using a spot board at all and investing in a bucket trowel about £5 or even get a brickies trowel and cut it down square, that way you can get your plaster as you need it out of the bucket. This will let it hang on a bit longer as a spotboard especially a wooden one (even soaked) will still take the moisture out of your mix quicker. Another thing to remember is not to have doors or windows open with a breeze blowing directly on to your wall as that will also dry it quick. Thats about all I can think of to help begginers but there really is no sustitute for timed experience.
Cheers
Hope this helps

and don't have your central heating on, you will regret it!!