Tools required: Large bucket, gauging trowel, Electric Mixer Drill, Spot Board, Finishing Trowel, Hawk and 1' and 4' clean paint brush. Materials: Bag of Board Finish Plaster or Multi-Finish Plaster, Clean Water.
1. Having applied scrim tape to the joints and nail heads of the wall that you are about to skim, mix the correct amount of plaster to a smooth creamy consistency. Having pre wet the spot board pour the plaster on to the spot board.
2. Having also wet your hawk and trowel, now load the plaster on to the hawk. To transfer the amount of plaster from the hawk to the trowel pass the trowel over the plaster on the hawk and 'squeeze' the plaster onto the trowel creating a 'sharp' wedge of plaster on the edge of the trowel.
3. Dividing the wall into three horizontal sections is a easy way when learning to apply plaster to the wall, start plastering at the top left (Note: if you're left handed start at the top right) of the top 1/3 of the wall moving across to the bottom right of the top 1/3 of the wall. Apply an even coat of plaster across the area of about 3mm in depth. Once you have covered this top 1/3 move down and repeat the process on the middle third. Once this is covered repeat on the bottom 1/3. This process or 'pattern of three' will enable you to maintain control of the wall and predict the way in which the plaster will go off. It also helps you to know where you started using a new mix if you run out of plaster half way through a wall. Now smooth this first coat so that edges and corners are 'sharp' using the wet small brush or edge of the trowel. Also, now smooth the wall following the 'pattern of three' to a relatively smooth finish.
4. Now make a second mix of plaster and apply. This is the laying down coat. The first coat was called the roughing on coat. Follow the exact same 'pattern of three' and this time aim for a smoother finish but without delaying the process of getting the entire wall plastered. Always remember that plaster will only remain workable for between 10 and 20 minutes prior to putting it on the wall.
5. Once you have covered the wall you can now do a first trowel on the wall to get it smooth. Again follow the 'pattern of three',making sure holes are filled in and lines flattened. This is really your last chance to get the smooth finish that you require removing large lines and holes.
6. The next step is to trowel the wall in three sets of three trowels. The first set of three trowels is when the wall is becoming firm and you should trowel the wall with single stroke of the trowel three times. Up to 15 minutes later and using a moist 4' brush, brush the wall ahead of the trowel during the 2nd set of three trowels. This will help to lubricate the passage of the trowel over the drying plaster and prevent dragging.
7. Now up to 40 minutes later when the wall feels as hard as it does when set you can use the same technique as the 2nd trowel above to give a final finish to the plaster. This set of three trowels is done in the 'pattern of three' and enables you to maintain a consistent finish across the wall. The final finish should be dull in appearance yet smooth to the touch.