Mixed incorrectly could lead to the need for rework, additional
costs or even the formation of structural damage. Mixing done right – a
“how to” guide from Festool
Efficient
and reliable mixing is the ideal basis for processing plaster and filler
The
importance of correctly mixing materials in powder form is often
underestimated. Philipp Stahl, master painter and application engineer at
Festool, describes why this process in particular is so crucial. The
combination of stirrer and stirring rod also plays an important role in mixing
and stirring and needs to be tailored to the relevant material on a
case-by-case basis.
Painters
encounter a multitude of different materials in their everyday working life: Various types of plaster, filler, paint, wallpaper paste,
clear coat, reinforcement adhesive, varnish and two-component coating systems.
As a rule, these materials each require a different choice of stirring rod.
In everyday work, painters often use the same stirring rod for different
materials. The result is that the materials are often
mixed incorrectly. This could lead to the need for rework, additional costs or
even the formation of structural damage. What is particularly aggravating
is that the material manufacturer’s warranty could also be rendered void due to
incorrect application. For the painter, this usually ends in substantial
follow-up costs and potential compensation demands from the end customer. This
risk can be easily avoided by simply using the correct stirrer, stirring rod
and settings in accordance with material manufacturer specifications.
Of paramount importance: Surface preparation
In demanding work processes – such as laying floor coatings
using epoxy resin or PUR – the material is made up of two components. During
mixing, it is especially important to ensure that the quantities and proportion
of components A and B are carefully and accurately balanced, that the timings
specified by the manufacturer are kept to and that the components are mixed
properly. If this is not the case, damaged areas may form on the coating and
adhesion issues with the underlying surface may crop up. During mixing, it is
recommended to peruse the component manufacturer specifications on the
designated data sheets and to keep exactly to the specified quantity
proportions and mixing speed. “If the components are mixed at too high a
speed, the mixture heats up faster. This means the material sets too quickly,
impairing adhesion with the underlying surface and reducing the processing
time,” explains master painter Stahl. He continues: “When using
liquid resins, we recommend a so-called disc stirrer which ensures that the two
components are mixed in the ideal way.”
Self-levelling filler for the floor
Painters are increasingly using self-levelling filler when it
comes to flooring in order to create an even underlying surface for the
decorative floor coverings, laminate or prefabricated parquet which are to be
added later. Mixing self-levelling filler incorrectly could make it form lumps.
This results in a residue of dry material – usually at the bottom of the
bucket. Using a classic stirring rod that is spiralled to the right could also
introduce an excessive amount of air into the material. This would result in
the material not mixing into a homogeneous mass, even after long periods of
stirring. This leads to damaged areas with some material remaining in powder
form or air bubbles on the surface – these appear when too much air has been
introduced to the mixture. “For this reason, it is recommended to use a
suitable stirring rod and to ensure that the speed and stirring duration remain
in accordance with manufacturer specifications. For this particular job, we
recommend using the whisk as its special design lets hardly any air into the
material and reliably forms a homogeneous mixture,” says Stahl.
Firm filler and plaster for walls
“In order to mix viscous reinforcement materials and
plaster, we recommend using a stirring rod that is spiralled to the right and
which mixes the material from the bottom to the top. This ensures that all the
material is mixed evenly,” describes Stahl. In order to agitate clear
coats, dispersion adhesives, wallpaper paste or thin materials, the application
engineer recommends using a stirring rod that is spiralled to the left and mixes
the material from top to bottom.
It’s all down to the perfect stirrer
For the vast majority of mixing materials, both in liquid and
solid form, Festool recommends a stirrer with at least 1200 W and two-gear
transmission with variable speed settings for mixing lightweight and medium
materials. “In addition, thanks to the patented ErgoFix height adjustment
feature, our stirrers can be individually adapted to the height of the
operator. This makes a natural, upright and effortless working position possible.
At the same time, the ErgoFix adapter, with its classic M14 tool reception,
makes it possible to quickly change stirring rods (FastFix function) without
the need for tools,” Stahl adds.
Heavy, compact materials should be stirred in first gear
since the high torque means that the maximum stirring force is readily
available. Meanwhile, liquid materials should be stirred in second gear at the
appropriate speed (see manufacturer specifications). If the wattage of the
available stirrer is too low, it requires a lot more effort to mix the material
perfectly since the missing power often has to be compensated for with physical
input.
Correct mixing enables painters to achieve the desired
working result as well as avoid unnecessary hassle and the consequent expensive
rework.
Philipp Stahl (master painter and application engineer at
Festool Germany)
Top tips
Before acquiring a professional mixing system, think about
what requirements you encounter in your work and which materials you generally
need to mix
Match the suitable stirring rod to each application/material
Observe manufacturer specifications
Adapt the speed as required and keep to specified mixing
times
Product list: recommendations from Festool
MX 1000/2 stirrer
Stirring rod: HS 2 R with ring (for
mixing firm filler and plaster)
Stirring rod: HS 3 R with ring (for
mixing plaster, screed, filler and adhesive mortars)
Stirring rod: HS 3 L with ring (for
mixing thin materials such as paint and varnish)
Stirring rod: WS disc stirrer (for
mixing paint and liquid epoxy resin)
Stirring rod: CS whisk (for mixing self-levelling filler)
For more
information about the unique Festool products contact Vermont Sales on
0113147711 or visit their web site www.vermontsales.co.za Festool is
available from leading specialist outlets country wide for information on your
nearest outlet call Vermont Sales, or go to
www.festool.co.za and click on
dealers
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