Do I need dust extraction and why should I dry sand?

27th March, 2014

Author: The National Collision Repairer


The process for dry sanding and dust extraction explained


The hard truth according to Paul Maclean, Business Development Manager at Festool Automotive Systems is yes to both questions! In this article he covers what he sees as a simple four step process for the best working practice and efficiency in the shop.

We so often see features and articles on dry sanding and dust extraction talking about the tools and the abrasives for use in this area, but it is not very often that the correct process for using these products are discussed.

Festool’s Paul Maclean states that in this day and age of best working practices it is essential that the time taken to complete a job in the panel shop or paint shop is carried out in the quickest time possible without losing quality. Yet when we visit a large majority of shops most have already got the right equipment and consumables but a large portion of them are not using it as either the panel beater or painter does not want to use it. They would prefer to use a sander without extraction or wet sand, but why?”

Generally a shop does not get paid for cleaning out a car full of body filler dust, they do not get paid for polishing cars and no paint company in the world recommends wet sanding, yet there are still a lot of end users doing all of the above. This all comes down to TRAINING, showing someone how to carry out the right process in the correct manner will result in higher efficiency’s. It is also the ability to want to change for a Faster, Easier, Better working process.

Effective paint surface preparation in only four sanding steps

In all workshops, it is essential to produce an optimal surface for paint application. Is it possible to achieve the required surface quality any faster and more effectively? Using a simple 4 step process this can be achieved.

Detailed mode of operation: P80 – P180 – Panel

For removing OEM paint and initial sanding of filler, Festool recommends using Granat P80 together with the Multi-Jetstream sanding pad. Their Granat abrasive is a grain blend of hardened aluminium oxide and ceramic, this will ensure long service life and high material removal capacity. The durability is a particular advantage when the abrasive comes in contact with metal during sanding of the repair filler, as the abrasive remains sharp. The concept of the Multi- Jetstream pad is to help with fast extraction of dust, reduction of heat on the pad which in turns reduces the clogging on the abrasive.

For the second step, which is basically feather edging the repaired area Festool recommends Granat P180. This grit enables excellent coarse sanding. Both these processes are used with the new LEX3 150/7 or 5mm air sanders which are hooked up to the new IAS 3 light hose (Intergrated Air System) and used with a CT26 or CT36 dust extractor.

Both the Lex3 air sander and IAS hose play an integral part of the system solution approach that Festool employs , the main advantage of the hose and sander to a Bodyshop owner is that the sanders cannot be used without being hooked up to an extraction unit. This in turn forces the operator to use dust extraction and keeps the general area in which they are working “dust free”, therefore eliminating the dust at the source.

P280 – P400 – Paint

This is where some operators say that are not going run a machine over a repair they have done, again if this is shown how to be completed properly it is a far more efficient and cleaner process than what is sometimes taking place.

Once the guide coat is applied to the primed area you then use the required sized hand block with Granat P280, once this process is complete you should always prep solve the area, this actually removes any fine dust that is sat in the P280 scratch mark pattern. The guide coat is then applied again, the final stage is to use the LEX 150/3mm with a thin interface pad with a Granat P400, and this is to solely remove the P280 scratch marks.

For those areas that are hard to reach (i.e. – around door handles, etc.) this is done by hand using the Granat Hand Pads, these range from P120-P800.

Blending of adjoining panels

This is one of the main areas where most shops can come unstuck, there is a large no of shops that carry out some form of dry sanding process but when it comes to blending they go over the area sanded with some form of prep paste, water and an old scourer. This creates a lot of mess, unnecessary clean up, time wasting and does not give a uniformed finish.

To significantly speed up this process Festool recommend using Granat P800 grit on the LEX150/3 this will reduce the film build on OEM paint, sometimes if the film build is not reduced in can result in the color looking darker when refinished. Finally you can go over the whole area using a Platin2 P2000 disc with the Festool Finish cleaning solution (493 066), the cleaner is misted onto the panel to be sanded and also the disc to keep it moist, this will give a complete even scratch pattern that will never show through when using a gold or silver colour for a fade out and will result in no re-work.

More Throughput

By changing to this blending process can save you 15mins per job, if an average shop is producing 25 cars per week, this can save you approx 6 ½ hrs per week ! There is an opportunity to put 3 cars more per week with the same amount of staff. These are the reasons why switching to an efficient dust extraction dry sanding process is the right decision.

System Solutions – Mobile v Boom Arms v Centralised Turbine

Every shop is different in layout, staff and procedures, but what Festool can offer is a very easy 4 step process that can be adapted by all operators, this can actually eliminate excessive stock holding and consolidation of various other consumables products.

Depending on the size of the shop, quality of air supply and if a ring main is installed will depend on whether an air tool system or electric system is more to suited to the shop.

Various systems are available from a basic dust extractor with an electric sander to a Centralised Turbine system complete with 6M Boom Arms. What works best for your shop ? This will always depend on the space available, is it an existing building, a new shop design or is it a small shop where you would like everything of the floor.

There are many contributing factors as to what system you should install, they can all achieve the same result but it comes back to how efficiently that result can be achieved with minimal mess. Pictured below is various options that are available between mobile, energy boxes , Boom Arms and Centralised Systems.

Festool Training / Demonstrations

Festool has numerous Technical Service Consultants (TSC’s) based in each state across the country that can carry out demonstrations and assist with training. Call our customer service line on 1300 063 900 to arrange a demonstration in your area.

The National Collision Repairer Magazine Editor: With most shops under more and more pressure to become more efficient and profitable, we thought that this was a timely article with some sound advice and ideas.

 

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