Mix setting too quick to use

by Chris K
(Derby England)

Hi I am using a multi finish plaster and mixing to the correct mix as per bag. 25kg to 11.5li of clean water. I have tested a 5kg mix with 2.3litres of water but the mix is solid within a couple of minutes before I can get it on the wall. What am I doing wrong. Thanks

Hi Chris
You should have about 40 minutes working time to apply, unless it is very warm. I have no idea how much water per quantity of plaster, Just go by feel, when mixing - pull the whisk out and it should leave a peak of an inch or so, as described in the mixing plaster video.

The plaster can set quicker due to:

old plaster (check use by dates, also if stored in damp conditions it may be no good)

Warm water, or dirty water

Or is it firming up, as opposed to setting:

Is plaster mix being tipped out onto a surface that draws the moisture out of mix. Use either a non porous surface or if using a wooden board, ensure it is soaked down first.

Hope that helps

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