How long between bonding coat and skim?

[finniman]

Hello plasterers, I have done a fair bit of skimming but don't have much experience of base coats/rendering.
I am going to be skimming a wall this weekend but I think it will need a bit of levelling in places to make it good. The base is a mixture of painted plaster, render and filler that has been painted with a damp proof paint. It will be coated with Wickes plaster bonding agent to give it a good key before I start.

If I use bonding coat as a base coat to build up the low areas (up to about 6-7mm in places) how soon can I skim onto it? Or can I make up this depth with skim coat? I want to get it done in a day if I can. Also, what is the best plaster to skim with, multi or board finish, I have read mixed views on multi and also that you can use board on any low suction background?

Many thanks

 

[PrenticeBoyofDerry]

You can plaster on to your base coat as soon as it has stiffened up, does not need to be dry.
As to which finish is better I stick to the multi for based walls and the board finish for you guessed it
Make sure any loose plaster and paint is removed from wall and any dirt or grime too, before PVA is applied.

 

[Richard C]

If I use bonding coat as a base coat to build up the low areas (up to about 6-7mm in places) how soon can I skim onto it?

Skim the same day whenever possible, as soon as the Bonding has gone off; usually an hour or so after mixing.

Or can I make up this depth with skim coat? I want to get it done in a day if I can.

Use Bonding; you can easily finish it in one day as above.

Also, what is the best plaster to skim with, multi or board finish, I have read mixed views on multi and also that you can use board on any low suction background?

Mixed views on Multi I use board finish occasionally but only ever on PB; I generally use Multi over base plaster/render & plasterboard, more for convenience than anything else but it will also give you a little more time over boards. Board finish will go off too quickly for you over Bonding.

 

[wozza56]

You could always use Wikes onecoat plaster,it doesnt quite give as smooth a finish but would be done in one hit and is easy to work with

 

[youngroughcaster]

leave the bonding till it starts to go dark then apply 2 coats of multi finish.If you put your skim coats on while the bonding coat is to wet you will get blisters in the skim coats which are hard to get rid of.


youngroughcaster

 

[Happyplumber]

to make the bonding go off a little quicker when you are doing patch repair ,just add a bit of multi finish into the mix

This way you are gurunteed to let it set and skim the same day

 

[letinman]

old post i know but i wondered why the advice is different or am i reading wrong

do you skim when the bonding (hardwall) is damp but stiff ie thumb proof but not finger nail proof , or do you wait till it is proper hard ?

thanks in advance

 

[huddsspread]

IMO i like to bond one day and skim the next. Unless the bonding goes rock hard in an hour or two. If its still wet, you get blisters and you have to keep troweling till its ROCK hard, the blisters wont go in the skim till the very last few seconds.

If you can, bond and skim as far apart as you can, say 3 hours. Or just skim it the next day if you have a load to do.

Thats what i'd do, but others may and will be different.

 

[stevethespreader]

ive just come off a site where there was a lot of price work the pace was fast, whole rooms was getting float and set in 1 day by 1 spread
i was there on day rate but there was others there on price work and they were floating and setting a whole room in a day "each" they were floating in the morning and then they would skim the room all in one go, the rooms was average size and they wasent waiting for it to go dark either ,(yes they did get blisters but are experienced enough to deal with them)
to the op i would take youngroughcasters advice

 

[letinman]

thanks Guys

I skimmed wall it was firm but not dark, first skim was good and flattend of nice had a few spots to sort , did 2nd skim and i put it on thinner and wetter , left it a bit long and it was well hard to flatten off so although looks ok was not great unfortunantly , i have left it slightly lower than the plaster either side ( have fixed large area on chimney breast)
so a real spread can skim the whole wall for me at a later date, overall it was good and i think with some tuition i could be a reasonable spread
thanks for the advice

 

[huddsspread]

if it was well hard to flatten, you were b@lloxed really. If you left the first coat too long, you will never bring it back. That is why i put the first coat on, and then put the second on straight away. I flatten the first coat with my 2nd coat, i just push all the bumps out. But i can do this as ive been a plasterer for more than 5 minutes, and not been on a course. ( thats not having a dig at you, you've had a go and done your best ).

In the future, to make it easier, first coat, wait 5 minutes and second coat. In the five minutes the first coat will pickup a bit, so your not just pushing the first coat around.

Again if you leave the first coat too long, you may as well hack it all off, or wait till the next day and start again.

 

[letinman]

if it was well hard to flatten, you were b@lloxed really. If you left the first coat too long, you will never bring it back. That is why i put the first coat on, and then put the second on straight away. I flatten the first coat with my 2nd coat, i just push all the bumps out. But i can do this as ive been a plasterer for more than 5 minutes, and not been on a course. ( thats not having a dig at you, you've had a go and done your best ).

In the future, to make it easier, first coat, wait 5 minutes and second coat. In the five minutes the first coat will pickup a bit, so your not just pushing the first coat around.

Again if you leave the first coat too long, you may as well hack it all off, or wait till the next day and start again.

hi thanks for the reply
I dont think i left the first coat too long as it flattened of well ,it was the second coat i left too long, but i see what you are saying
dont bother flattening the first seperatly just do it together with the second

ps
i have not been on a course and do not think i am a spread , i am a spark and have worked in the building trade for 15 years i am just trying to sort out the wall so that we dont stare at bricks etc until the wall is extended at which point i will pay a real spread to do the whole lot.

 

[huddsspread]

At least you have some tips for next time.

You can always skim it again! It'll be better 2nd time round.

 

[letinman]

At least you have some tips for next time.

You can always skim it again! It'll be better 2nd time round.

true
if i skim again how long roughly is it to wait before flattening of and should i use a bit of water to lubricate the trowel ?

 

[dawsonplastering]

if i skim again how long roughly is it to wait before flattening of and should i use a bit of water to lubricate the trowel

This comes with experience mate trial and error i tend to flat and fill straight after ive put second coat on getting the coat as good as it possibly can be. this makes the next few trowels easier water isnt really needed till about
third trowel or if its drying quick second trowel trick is to try get your wall flat before it goes off then the rest is easy