Materials for Skimming
There are many finish plasters available and they all have different characteristics. One of the easiest finish plasters for a beginner to use is – 'Thistle Multi Finish'. Being used my most professionals it is widely available and can be used on any surface.
The plaster should be mixed in a bucket with a whisk attached to a drill. Always put the water (clean, cold tap water) in the bucket first. If you want a full bucket full of plaster then the bucket will need to be half filled with water. By the time the plaster is added it will almost have doubled in volume.
'Multi Finish will set within 1½ hours - but remains workable for application for around 3/4 hour. You should aim to have applied the plaster during this time. It is always advisable to clean the bucket as soon as it has been emptied.
Old plaster or dirty water can bring the setting time down to as little as 5 minutes. Any unused plaster in the bag should be properly sealed and if not going to be used within a few weeks - placed in a secondary plastic bag to keep the moisture out.
Clean water must be used for mixing - especially not water that may have old plaster in it from cleaning tools previously. If during the skimming process another batch of plaster needs to be mixed then it should be kept separate from a previous mix – as they will be setting at different times.
If you are skimming on to plasterboard then all joints should first be taped up with plasterer’s jointing tape (sometimes referred to as 'scrim'). This will stop the joints cracking. The tape is self adhesive. If you have any big gaps then sometimes two layers of tape may be beneficial.
No matter how good your technique is - if your trowel is not prepared properly them it can be impossible to be successful with your plastering finish.
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The author cannot accept liability for the use of any of the materials or methods recommended in this manual or for any consequences arising out of their use. The author cannot guarantee the suitability of any recommendations made in this manual and shall not be under any legal liability of any kind in respect of or arising out of the content of this guide.