drying to quick

by Stephen

Have applied pva and skim onto plasterboard (old) butwent off in half an hour making it impossible to Finnish. . Help.

Hi Stephen,

Did it set or dry within half an hour?

If it set this quickly - the plaster must have been old or dirty water used. In which case - easily rectified.

If it was drying too quickly then the following may help:

1. Suction. The suction on Plasterboard should be fine as it is relatively low suction - but as you say - if it is old and providing
High suction it can be controlled with PVA. It is not unusual on very porous surfaces for 3 coats of PVA (the dilution increasingly thickened) to be applied. The PVA should stay wet for at least 20 minutes, if it becomes tacky with 10 minutes then another coat may be needed.

2. Plaster consistency. The peak test will ensure that the plaster is not too thick. When the whisk is pulled out of the plaster - it should leave a peak of about an inch.

3 Environment. Ensure the room is not too hot - or a breeze is not drying out the plaster.

Workability time. The finish plaster should stay workable and possible to apply to the wall for at least 30 - 40 minutes.

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