Should I let bonding dry out before applying a finish coat ?

[MrTeeny]

or am I OK to apply the finish coat when it's started going off ?

Only an area of around a couple of square metres where I removed a fireplace

Thanks

 

[noseall]

if bonding is applied in the morning, you can skim it in the afternoon.

it does need to 'darken' first.

 

[roughcaster]

If you put the finishing coats of plaster onto bonding coat before it has SET, you will end up with an area full of blisters and "bubbles" that are very difficult to get rid of,as Noseall said,"it needs to go dark"in colour,then you know it has set.When you put your finishing coats (2) on,it too will go dark when it has finally set.

Roughcaster.

 

[noseall]

If you put the finishing coats of plaster onto bonding coat before it has SET, you will end up with an area full of blisters and "bubbles"

....yeah and they are a ba$tard to get rid of too.

 

[onion]

If you put the finishing coats of plaster onto bonding coat before it has SET, you will end up with an area full of blisters and "bubbles"

...

.yeah and they are a ba$tard to get rid of too.

newspaper

 

[roughcaster]

I have used newspaper before on areas of concrete floors to soak up excess moisture that has come up to the surface.We would put dry cement on top of the paper to give it extra "draw",works great. Somehow,I don't think that would work on Bonding coat plaster.If the float coat of plaster has set properly, there is an amount of suction on the wall which draws the moisture from the finish coat back into it,so any blisters etc are minimal. Bonding coat plaster can be notorious for being slow to set.The worst case scenario is when you put the finishing plaster on too early and it goes off (sets), but the bonding coat underneath, in places, has not properly set.You will get a surface of the moon effect,and no matter what you do,you only push the blisters down in one place and they come back twice as big in another. Let it set properly underneath, then no problems.

Roughcaster.