Contractor Education Archives - Lägler North America

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Lägler Premium Abrasives

Most abrasives are produced for other industries or for stationary belt sanding machines. These machines are mainly used to sand raw wood at a set speed, RPM and pressure. Those abrasives are then converted to sand hardwood flooring.

Our approach is different.

We know that our customers face challenges with raw wood, factory prefinished wood, on-site refinished wood and endless types of finish. Our machines offer variation in pressure settings and individual machine RPM, as well as personalized walking speed, which affects the sanding pattern. For this very reason, only the best abrasives could be paired with our machines. The LÄGLER® team tirelessly researched to find the right backing, minerals for abrasive grain, coating bond and base bond for our abrasives to get consistently premium results for premium floors.

Abrasives Composition

Choosing the right abrasive is one of the most important decisions in achieving a premium surface. Proper matching of the backing, bond and abrasive grain is particularly important for a high quality abrasive.

Backing serves as the base for the abrasive grains and the bonding system.There are generally two backing variations- textile and paper. The greater the loading caused by the sanding process, the more resistant the backing needs to be. The bond fixes the abrasive grain to the backing. A distinction is made between the base bond, which anchors the grain on the backing, and the coating bond, which connects and stabilizes the grains together. Depending on the area of application of the abrasive, softer or harder bonds are used. Generally in the wood sector, synthetic resins are used as bonds, which have a very high resistance to heat.

Abrasive grain consists of hard cutting materials that ensure material removal. The size and dispersion of the individual abrasive grains, as well as the type of cutting material, play a critical role.

Abrasive Minerals

Aluminum Oxide (Red/Brown)

Aluminum oxide, also known as corundum, is hard and has a high temperature resistance. Due to its hardness, as machining time increases the cubic grain becomes increasingly round and relatively blunt. This process happens fairly quick, resulting in a shorter service life.

Zirconium Corundum/Zirconia (Blue)

Zirconium corundum is very tough and is also extremely temperature resistant. This gives it a very long service life, which in turn minimizes costs. Zirconium corundum has a self-sharpening effect owing to its microcrystalline structure. Due to this structure, during the sanding process small parts break out of the grain again and again. This results in new cutting edges which keep the grain sharp for longer periods. The microcrystalline wear ensures aggressive sanding and lasting sharpness, which in turn extends the entire service life of the abrasive.

Silicon Carbide (Black)

Silicon carbide abrasive grains are wedge shaped and pointed. They are sharp edged and very hard, making them extremely aggressive. Therefore, silicon carbide is used in the wood sector mainly for very coarse grit sanding. In fine sanding, silicon carbide is almost exclusively used for sanding screens. Since silicon carbide is relatively brittle, the individual grains wear away faster than other minerals.

Abrasive Dispersion

Abrasive dispersion affects the sanding pattern through the cutting and removal process.

The grain is usually applied with an electrostatic scattering process in such a way that the respective tips are all aligned upwards. This ensures a high initial cutting performance. In the production of abrasives, the respective grain size can be dispersed in different densities: open, semi-open or
closed dispersion. Abrasives with an open dispersion achieve a high abrasion rate, but exhibit a certain aggressiveness that can have a negative effect on the sanding pattern. In order to avoid the high, punctuated aggressiveness of the open dispersion and the associated sanding marks, the grains are placed close together on the abrasive. This means that the aggressiveness is no longer localized but instead evenly distributed over the entire abrasive surface.

In order to meet constantly growing customer demands, LÄGLER® prefers closed dispersion in the production of abrasives, especially on medium and finer grits. This ensures optimal aggressiveness while simultaneously leading to a uniform sanding pattern.

Want to try LÄGLER® premium abrasives for yourself? Click here to purchase.

Prevention of Sanding Marks

The last thing you want with a floor you’ve sanded and finished is to have sanding marks pop like neon signs in the night. If you can spot sanding marks
while standing at full height on the floor and looking only with ambient light, then something went wrong.

This final blog post that comes from Lägler’s “Sanding of Wooden Floors” manual (free download) lays out the reminders of how to avoid sanding marks ruining
your success on the job.

Tips to Prevent Sanding Marks

The wood flooring and expansion gaps or the staircases always should be thoroughly vacuumed immediately before each work step (every sanding step, gap
filling or surface treatment).

Here are some general tips to keep in mind:

The abrasive must be suitable for the respective machine and should not be damaged.
The abrasive must be correctly attached and fastened.
The wheels should not be soiled or damaged.
The V-belts should not be soiled, damaged or worn out.
The pulleys should not be soiled, damaged or worn out.
The machine operation must be uniform and adapted to the corresponding process.
The grit sequence must be followed.

Drum and Belt Sanding Machines

The sanding pressure setting must match the abrasive grit to be used.
The side wheels must be set so the sanding drum sands in the center.
The lowering rod must move freely and not jam.
The sanding drum should not be soiled or damaged.
The tension roller of the assembly should not be soiled or damaged.
The sanding drum must always be lifted from the floor before the machine is turned on or off.
The sanding path displacement always should proceed from left to right.
The displacement from one sanding path to the next should not be too far out.
The sanding direction must be selected to match the laying pattern of the wood flooring.
Excessive pressure should not be exerted on the sanding drum during sanding.
- No additional weight should be placed on the machine.
- The rear portion of the machine should not be lifted by the handle during sanding.
- The lowering lever should not be pressed down during sanding.
- As soon as it is determined that the subfloor or wood flooring tends to vibrate, the sanding steps must be executed as early as possible, using
  the three-disc sanding machine instead of a drum or belt sanding machine.

Edge Sanding Machines

The wheel setting must be adjusted to the respective attachment.
The two wheels must be set to an equal height.
The sanding plate should not be set too steep. Otherwise, digs can result.
The sanding plates overlay must not be damaged.
The abrasive must be firmly positioned in the center of the sanding plate.
The machine always must be tipped slightly back so that the abrasive is lifted off the floor before it is switched on or off.
The machine must always be guided with circular movements during sanding.
Excessive pressure should not be applied to the attachment during sanding.
To increase the abrasion of the machine, change the angle by adjusting the wheels.

Three-Disc Sanding Machine

The abrasives must be firmly positioned in the center of each sanding plate.
The three sanding plates must be identically equipped.
The sanding plates must be correctly installed and attached.
The flexible Velcro rings should not be damaged.
The flexible Velcro rings must be used with abrasives coarser than 60 grit.

Visible Sanding Marks After Surface Treatment

Brightness differences:

The finish coat was accidentally sanded through at certain spots during the intermediate finishing sanding, which later leads to differences in the brightness
on the completed finished surface.

An abrasive with a different grit and cutting material was used for the edge sanding as for the previous field sanding.

Cloud formation:

Glossy spots can be seen on the surface (cloud formation). The same abrasive was used for too long in the last sanding step that it became too blunt. Excessively
blunt abrasives burnish the wood surface.

The wood absorbs less finish on burnished spots. This causes differences in the brightness.

The abrasive must be changed frequently enough to prevent burnished spots.

Visible sanding marks:

The final sanding step was performed with an excessively coarse grit. Oiling requires finer sanding than finishing.

For the full rundown of how to get the most out of your sanding machines, especially if they are Lägler machines, read each post on this blog.

Or, better yet, download Lägler’s free PDF, print it out, carry it on your phone,
whatever will help you and your crew be the best you can be.

Hands-on training and instruction are available through Lägler’s one-day Premium Sanding Technology (PST^®) certification course, too. Call 800-848-6635 to schedule your session in Denver.

Tips for Finishing Wood Floors

The past several months we’ve laid out how-to tips for using the big machine, edger, multi-disc sander and buffer.

It’s a series of blog posts at your fingertips, but it’s also based on an industry-leading instruction manual written by Karl Lägler, “Sanding of Wooden
Floors,” which is available for download at laegler.com.

Now, let’s finish the floor.

Before you start finishing a wood floor, take these key tips into account. It’s the details that make the difference between getting a referral or getting
a call back.

Checklist to Prep for Wood Floor Finishing

The wood flooring should not have any defects or damages.
The field must be dry and free of oil, grease, wax, resin, cleaning agents, old coatings, and substances containing silicone.
Make sure all windows and, if possible, doors are closed and the air conditioning is turned off to prevent drafts.
Make sure everything in the room (e.g. door frames, window sills, heaters, wood flooring, expansions gaps) is thoroughly vacuumed immediately before
starting the finishing work. Don’t let dust kill your finish job.
Close the blinds, if possible. The surface must dry after every finish coat without being exposed to sunlight.

And it’s important to always follow the processing instructions in the finish manufacturer’s data sheets (e.g. coating quantity, method, processing temperature,
residence time, drying time).

Tips for Wood Floor Finishing Success

Use a small finishing roller or paint brush to finish the areas around the heater pipes, door frames, corners and similar points.
Then use a large finishing roller or applicator to evenly coat the remaining field working towards the door. Try to work with the light so that you
can observe your work and avoid unevenly applied finish and missed spots.
Finishing at excessively high temperatures (see the finish manufacturer’s data) is not recommended since the excessively fast drying can cause poor
distribution of the finish, visible transitions or trapped air. Do the work early in the morning or late in the evening with adequate artificial
lighting, if needed.
Make it super-clear to homeowners the wood floor should not be used until the finished surface is completely dry (observe the finish manufacturer’s
data).

Tips for Avoiding Customer Callbacks

Upfront communication goes a long way. As an expert in wood flooring, sometimes it’s easy to take for granted what the “basics” are and forget that homeowners
are relying on you to educate them through every step of the process.

Let your customers know:

The options in modern finishes, and the requirements (e.g. safety, drying time)
Differences in the absorbency of various wood species can lead to deviations in the brightness of individual elements after finishing
The industry expectations for evaluating a finished floor are to view it from an upright, standing position in normal, ambient lighting.

And remind your crew that clearly visible brush strokes or material accumulations can be costly. If the customer complains about such defects, it could
lead to resanding and finishing the job – and an unhappy experience for you and the customer.

Finishing Methods

After you have thoroughly vacuumed the wood flooring and expansion gaps …

Wood Floor Finishing Using a Primer

Most finishing systems consist of three layers. A primer is usually applied as the first coat. The primer ensures optimal adhesion between the wood and
finish, and reduces the side-bonding effect of the finish.

The surface is not intermediately sanded after the primer coating. Instead, the first finish layer is applied. The intermediate finish sanding step is
carried out after the first finish layer has dried.

Wood Floor Finishing Without Using a Primer

Three finish coats are required if no primer is used. Instead of the primer, the first finish coat is applied, and then the second and third finish coats.
In this case, intermediate finish sanding is necessary, following the first and second finish coats.

An additional intermediate finish sanding step can be carried out on heavily used wood flooring which was not primed before finishing. This is followed
by an additional fourth finish coat.

Each additional finish coat increases the total thickness of the finish and causes the wood surface to lose part of its natural appearance.

Finishing Floor Boards and Strip Flooring

Finish should generally be applied to floor boards and strip flooring in the lengthwise direction, since the finish can otherwise collect in the joints
or beveled edges. This leads to increased lateral bonding and stresses the wood flooring.

Intermediate Finish Sanding | Multi-Disc Sander or Buffer

The wood grains on the surface may become raised after the first finish coat. This makes the surface rough. It must be smoothed out by the intermediate
finish sanding step. Multi-disc sanders and buffers, each with sanding screens (generally using grits 100 to 150), are particularly suited for this.

Using a sanding screen with driver pad is less aggressive than hook-and-loop sanding discs. Since the surface only needs to be smoothed, the machine must
be moved quickly and at a low sanding pressure (without additional weight).

The edge areas where the finish coating is not yet sanded following the usage of the multi-disc sander or buffer should be sanded manually with a sanding
block or an orbital sander, and only at low pressure.

The same sanding screen – same material and grit — must be used for the intermediate sanding of the field and edges. Different degrees of roughness in
the field and edges otherwise lead to differences in the brightness. That creates a visible transition from the field to the edge area of the finished
flooring.

Ensure the finish coat is not sanded through. That will cause the sanded through spot to stand out as darker areas after additional finish coats.

The use of a used sanding screen is recommended to reduce the risk of sanding through the finish layer during intermediate finish sanding.

The wood flooring and the expansion gaps must be thoroughly vacuumed after every intermediate finish sanding step.

Airborne dust must be minimized otherwise it deposits on the freshly finished field and can lead to embedded dust.

To learn more, or to get more information to share with your crew, look through the Lägler North America blog.

Also, download Lägler’s free “Sanding of Wooden Floors” manual.
It’s written by the leading floor sanding expert in the world.

Tips for Final Sanding Wood Floors

We’ve been rolling through Lägler’s “Sanding of Wooden Floors”
manual bit by bit. We’ve talked about how to pull the best work out of your crew and your machines using the big machine, edger and multi-disc. But
the formula for wood floor sanding success isn’t done ’til you nail the final sanding step.

5 Tips for the Final Wood Flooring Sanding Step

1. The grit of the abrasive used for the final sanding step depends on the wood species and how you sanded the floor up to that point, what grit sequence
you used to get there.

2. Wood flooring generally must be sanded with a finer grit when oil or wax is being used. The grit sequence must run accordingly to include finer grits.

3. The deeper the sanding marks, the more oil or wax can penetrate and make these indentations appear dark. Deep sanding marks are much more visible than
with finishing sanding. The usage of colored oils and stains will even reinforce this effect.

4. An even and fine surface structure of the wood flooring is particularly important for colored oil or stain. The deeper the sanding marks, the more
color pigments can deposit in them. The sanding marks therefore appear even darker than with normal oil. A surface treated with colored oil or
stain is therefore generally sanded with one grit number finer than with other treatments.

5. But it is up to the contractor to make the call on whether the surface quality following the final sanding step is suitable for the planned surface
treatment. Make sure to follow the finish manufacturers’ instructions.

6 Points to Consider After Completing Sanding (Before Finishing)

1. No more cracks or joints should be visible. Otherwise they need to be closed by using filler.

2. No more sanding marks from the coarse grits should be visible. With the help of a flash light, existing marks will become clearly visible. Such
faults will stand out after the subsequent surface treatment, due to differences in the brightness of the field. This can result in customer complaints.

3. Differences in the roughness of the wood surface between the field and edge sanding lead to different brightness levels after the following surface
treatment (“picture frame”).

4. No more damage or the other defects should be visible on the surface after the final sanding.

5. The surface should be inspected for foreign particle residues (e.g. iron filings, plaster residue). Small iron particles can lead to brown spots
(rust spots) in the finish coating, especially if the floor is coated with water-based finish.

6. No contaminants such as oils, greases, wax, resin, cleaning agents or substances containing silicone should be present on the surface. These substances
can impair the bonding of the wood surface with the finish, oil or wax and lead to complaints by the customer.

These tips are printed in Lägler’s sanding manual. You can download a digital version of the manual at no charge at laegler.com.

We also cover the how-tos and what-not-to-dos in-person in Denver, during Lägler’s one-day Premium Sanding Technology (PST^®) certification training.
Call us if you dare (800-8-HUMMEL / 800-848-6635).

How to Use a Lägler TRIO

Those who don’t know call the Lägler TRIO a buffer. Only those who don’t know.

The way to feel what’s what is to get your hands on the TRIO and do some work – and to make sure you’re using it the right way.

That comes with getting some practice laps at the source: Lägler’s Premium Sanding Technology (PST^®) certification training.

Next best? Read what’s below. It’s based on Lägler’s “Sanding of Wooden Floors” manual (download free PDF).

How Best to Use the Lägler TRIO

The TRIO is designed with two functional advantages:

Produce a flatter surface than a belt sander when using the same grit abrasives
Sand in any direction, from wall to wall

Fine sanding using the TRIO generally begins with hook-and-loop sanding discs starting at 60 grit. You can sand with the TRIO up to 150 grit, depending
on the wood species and the subsequent surface treatment.

If you want to take it one step further, use sanding screens after the final sanding step. Use screens at the same grit as the sanding disc used in the
final sanding step.

One difference between the TRIO, the industry’s original multidisc sander, and a buffer is it packs the power for pre-sanding, too. You can use 40 grit
to smooth out minor over- and under-wood.

Fine Sanding with the Lägler TRIO

To create high-quality surfaces when using the TRIO for fine sanding:

Do not skip more than one grit number when pre-sanding with a belt sander
Do not skip any grit numbers when fine sanding with the TRIO

If you want less aggressive cutting with the TRIO:

Remove the additional weight
Attach two flexible Velcro rings to each sanding plate

These methods especially give you an advantage when sanding uneven engineered flooring, helping to prevent the top layer from being sanded through.

To increase sanding abrasion with the TRIO:

Remove the Velcro rings from the TRIO sanding plates
Decrease walking speed while sanding

Warning: Excessively slow walking speeds or continuous sanding in the same spot creates too much heat. That can cause burn marks on the wood flooring and
clogging of the abrasive. If a spot requires extra sanding, make sure to repeat sanding at appropriate time intervals.

The wood species and the surface treatment to be carried out after the fine sanding determines the grit number of the final sanding step.

Intermediate Finish Sanding with the Lägler TRIO

The TRIO can be used for intermediate finish sanding with sanding screens.

The application of a used sanding screen and the removal of the additional weight is recommended to reduce the risk of sanding through the finish layer
during intermediate finish sanding.

Sanding pads also can be used on the TRIO for the intermediate finish layer.

When sanding cork:

Never sand with abrasives coarser than 60 grit
Always remove the additional weight from the TRIO
Sand without the flexible Velcro ring on the sanding plates

Check surface quality and perform additional sanding steps depending on the result.

Last note: Clean the filter cartridge regularly.

Adding the TRIO to your roster of equipment is a next-level play. It’s for craftsmen who raise the bar for quality and give themselves the opportunity
to command a next-level place in their market.

We know it takes real commitment to the investment. We welcome you and your crew to join us for a one-day Lägler PST training class. Test drive the TRIO
and get started the right way.

NWFA Sand + Finish Training at Lägler N.A.

Guest Post by Brett Miller, NWFA VP of Education & Certification

For those of you who think you don’t have time for training, think again. Certainly, there is no better feeling than being “too busy” to take time off
for career development, but what if you could learn new skills that could make you more efficient, more valuable to your customers, and most of all,
more profitable? All of that is possible with National Wood Flooring Association (NWFA) training.

NWFA offers the most well-rounded, unbiased training available for wood flooring professionals. NWFA training provides attendees with the opportunity to
try a wide variety of products and equipment in a risk-free environment. Lägler North America will host the NWFA’s Intermediate Sand & Finish class
October 3-5 at its training facility in Denver.

This three-day event provides extensive hands-on sand & finish training for those with at least one year of experience. Attendees will learn:

How to approach different situations in the sanding process
How to refine scratch patterns
How and why it is important to produce a profile on the flooring surface adequate for the finish being used
Proper use and maintenance of tools
Repair techniques
Maintenance coats on existing floors
Select finishing techniques that will yield top-quality results

Other specific techniques will include board replacements, hand-scraping, repairing finish imperfections, and recoating/refinishing factory finished floors.
Techniques for working with the arid environmental conditions unique to areas like Denver, which impact the finishing process will be one of the unique
features of this class as well.

If you want to step up your game even further, and have the opportunity to be ranked at the top of our consumer website search, NWFA Certified Professionals Sand & Finish Certification
will be offered as well. Earning NWFA Sand & Finish Certification requires a hands-on test and a written test, as well as three years of sand &
finish experience.

[NWFA Sand & Finish Certification can be doubled with Lägler Premium Sanding Technology (PST) Certification,
in the same hands-on test.]

NWFA member Joe Avila, owner of Huggins Wood Floor Specialist in Westfield, NJ, shared the value of his NWFACP certification: “Many customers say they
found me on the NWFA Find-a-Professional search feature and hired me because of my certifications.”

Take the next step in your wood flooring career. Get hands-on with NWFA at Lägler North America. Space is limited. Sign up today.

How Best to Use the Lägler FLIP

It seems to be something like an open secret that the Lägler FLIP^® is engineered for versatility. The information is out there, in Lägler’s “Sanding of Wooden Floors”
manual and in some pieces already on this blog.

But we know how it goes. We haven’t read many manuals either – not for connecting a new device, assembling the kid’s new Hot Wheels race track, or whatever.

So, we’re laying out the essentials here on how you can get the most out of the FLIP.

The edger uses a 6” (150 mm) disc. It can be used to cut
aggressively, finely or on a medium setting, all adjustable with the turn of the rollers.

Sanding attachments can be “flipped” to swap out lengths and diameters, from everyday edging to reaching under radiators and cabinets, to sliding into
tight spots like corners and between spindles.

Versatility.

3 Tips for Using the FLIP

1. Sand clockwise. The FLIP is designed for edge sanding clockwise around a room. The sanding disc rotates clockwise, cutting at the 12
o’clock position. The fiberglass cover of the FLIP’s attachments has a cutout directly over the sanding zone, optimizing its dust suction capability.
(What the super-short video of the FLIP being used to vacuum a pile of dust, and you’ll see what we mean.)

What happens if I sand in a counter-clockwise path around the room? Moving counter-clockwise around the edge of a room will not damage the FLIP.
It will give you a more aggressive cut as you move the edger against the clockwise rotation of the abrasive, which, of course, also means deeper scratches
you will need to work harder to remove later. It also will decrease dust collection, because the clockwise rotation and the suction are designed to
work optimally together.

2. Take it easy. Do not press down. The FLIP’s design takes ergonomics into account. It’s built to make edging a
bit easier on your body. If you press down or lean your weight onto the machine, it will decrease the sanding plate speed and give you uneven sanding,
including burn marks. It also will put unnecessary stress on the machine.

So, take it easy. It helps you, the machine and the floor.

3. Choose the right grit abrasives at the right time. If you just sanded the field of the room with your big machine
using a 40-grit belt, use 40 grit on your edger. If you just edged with 80 grit and you’re moving on to your single-disc or multi-disc sander, use
80 grit with that machine.

The last thing you want is for the homeowner to walk in and be able to see a band around the edge of the room where it doesn’t match with the field. Successful
floor sanding is one of those mysteries you get to keep to yourself and let them wonder how you made their floor look so awesome. If they can see how
the magic is made, it ain’t being made well.

Bonus Tip: The white wheel that is screwed onto the top of the short/standard and long FLIP attachments is your wall roller. Notice the
track it sits in allows you to set the position of the wheel. Just loosen the screw, adjust the wheel to let you closer or farther from the wall, tighten
the screw.

How to Use the FLIP Corner Attachment

Don’t let the name of the FLIP corner attachment fool you. It’s not just for corners.

In fact, when this attachment is at its most valuable to you probably is not in the corners. It’s sliding between spindles, around tight spots with radiators,
getting around pipes, and anywhere else a 6” disc isn’t the machine for the moment.

The corner attachment has a 2 3/8” (60 mm) diameter. And it rips fast, with RPMs cranking almost two and a half times as fast as the FLIP’s short and long
attachments you do most of your edging with.

3 Tips for Using the FLIP Corner Attachment

1. Sand counter-clockwise. Yeah, that’s opposite of what we are saying above when sanding with the short
and long attachments. But, in general, you’re quick-hitting small spots where you’re not going to be running along the wall, right? Not much room to
run between spindles. So, this is just a heads-up, letting you know how the attachment is designed to be used.

2. Use the flexible Velcro ring. Always. Sand with the donut between the abrasive and the sanding disc.

3. Use the finest grit possible. Like a boxer, you want to minimize your time in the corners, don’t you? And keep
the bonus tip in mind, too …

Bonus tip: The speed of rip of the corner attachment sanding disc heats up the abrasive pretty quickly. Tip #3 above spotlights fine grits,
which will reduce some of the need to change paper, but when it’s time for a new abrasive, be aware the heat can melt the abrasive to the donut.

How to Avoid the Paper and Flexible Ring Sticking Together

1. Take a water break. Set the FLIP aside for a brief cool down period before pulling the abrasive off the machine.

2. Tag team. Keep a second donut and abrasive ready to go. You can swap in the fresh set keep grinding while the first set is cooling
down.

All this information is in two of Lägler’s manuals: “Sanding of Wooden Floors” and “FLIP Operation, Maintenance, Safety.”

Both are available for free download at laegler.com.

It’s also part of Lägler’s Premium Sanding Technology (PST^®) certification training.
You can schedule that for you and your crew with us in Denver, or make a European vacation of it by heading to England or Germany.

Sanding With A Big Machine

A lot of floor sanding pros probably are confident in their “how to sand with a big machine” knowledge. Many of you should be. Yet here we are talking
about it, so hang with us …

We talk with flooring pros everyday about basic techniques and why they are the best way to go. In Lägler PST^® training, when contractors and distributors
call us (800-8-HUMMEL, if you need it), at NWFA Expo,
answering questions via social media DMs – everywhere.

So, it’s worth double-checking your know-how and, at the least, you can send the new guy on your crew to this post and the many others we’ve put up on
the Lägler North America blog.

To help, here’s a list of the big machine blog articles we’ve posted in the past year:

If you have a copy of the Lägler sanding manual,
that’s the good stuff we base blog posts like this one on.

Choosing the Starting Abrasive Grit

We know when you start a job and get the big machine on the floor, you’re ready to rip. But how do you decide what grit abrasive to start with?

That decision right there – what grit to start with – can make or break efficiency on the job. It can lead to spending more time and money than you want,
if you don’t nail it.

If you start with too coarse an abrasive, you’re cutting deeper scratches that will take more effort to remove. If you go too fine, you’re creating more
work for yourself to go over it again.

Q: How do you know what grit you to start with?

A: Test sanding

Make your best guess of what grit belt to put on the drum to start the test, but go as fine a grit as you think will work. If the first grit you try isn’t
the one, move to the next grit you think is best. Testing doesn’t take long to do, and not nearly as long as the alternatives. It will save you headaches.

Always sand with as coarse a grit as necessary and as fine a grit as possible.

Below are two images from the Lägler manual, “Sanding of Wooden Floors.”

The first one shows how to approach grit sequence when using a multi-disc sander in your lineup.

The second one shows grit sequence when using the conventional setup, that is without using a multi-disc machine.

Learn more about best methods for using a big machine, multi-disc sander and edger. Read the Lägler N.A. blog and subscribe to the Lägler N.A. monthly email newsletter.

How to Test Floor Flatness with a Big Machine

Besides getting awesome Instagram shots on the job, of course, getting the floor flat is the most important part of sanding wood floors.

But that’s harder to get just right if you don’t take a few minutes to figure out the flatness situation before you get started. You’ve got to know what’s
out of whack with the floor so you can game plan how to make it the level of flat you – and the homeowner — want.

We know you know the feel of unevenness when you’re sanding, and sometimes it’s easy enough to see. But taking some minutes to mark out the uneven spots
will make the job easier.

Here’s a simple flatness test you can do with your big machine, before you start sanding.

Check Floor Flatness Using Your Drum Lever

Use these quick and easy steps to help you mark out high and low spots of uneven wood flooring. It will make those areas easier to see when you’re sanding.

1. Put a fine-grit, used abrasive belt on your drum.

2. Make sure your machine is turned off.

3. Lower the drum to the floor.

4. Roll the big machine at an angle across the boards, paying attention to the drum lever’s movement. If the lever moves up, the floor is rising. If it
moves down, the floor is sloping downward.

5. When the drum lever moves more than a little bit up or down, mark the area as high or low with a pencil.

If you do that to the whole room, you’ll be able to step back when you’re done marking out the spots and see the game plan laid out in front of you. High
here, low there. Low right over here, high over there.

These kinds of prep steps save you hassles later in the process. By doing everything you can to knock the floor flat upfront with your big machine, the
fine sanding steps will go much better. If not, the unevenness will continue through each step, making you have to work harder all the along the way.

Learn more about work-smart sanding techniques in Lägler’s “Sanding of Wooden Floors” manual. Download the full manual for free at laegler.com.

Want a chance to improve on a practice floor with Lägler at your side? Call us to set a date for you and your crew to get Lägler certified: 800-848-6635
(800-8-HUMMEL).

Learn more about Lägler Premium Sanding Technology (PST^®) training on
our blog, too.

Big Machine Sanding Direction, Speed + Pressure

Sanding wood floors is a science. Knowing that science is what sets you apart from DIY homeowners who want to save a buck and try their luck.

In fact, when a lifestyle blogger reached out to us a few days ago wanting some tips for an article on “refurbishing” wood floors, this was our answer:
Hire a professional. Then we laid out some truth on what it takes to be good at sanding floors, how someone who is inexperienced is virtually certain
to jack up his/her floors. Hire. A. Professional.

That said, even pros aren’t gifted at birth with knowing the science it takes to perfect a floor. Learning is a process that never ends.

For example …

1. We see photos on Instagram everyday showing people running big machines. Some are moving left to right across the room. Some are moving right to left.
Some run parallel to the straight-laid boards, and others cut at a slight angle across them.

Do you know … What’s the best way to sand a wood floor: moving from left or right, and parallel or at an angle? What might be exceptions to the rules?

2.Your big machine has variable pressure settings. For the Lägler HUMMEL, there are three – coarse, middle and fine – that can be chosen by use of a simple
lever. Other big machine models have their own adjustment mechanisms.

Do you know … Which big machine pressure setting should you use for what situation, and when?

3.Then there’s speed. How slow or fast you walk when using the big machine relates to the pressure setting and abrasive grit you’re using. How hard or
soft the species of wood you’re sanding has an impact, too.

Do you know … How fast (or slow) should you dance with your big machine? And what speed with what grit abrasives?

Sanding Direction: Left to Right vs. Right to Left

The HUMMEL’s eight-inch sanding drum is positioned at the right edge of the machine. The lateral wheel that trails the drum always rolls on the freshly
sanded surface.

Because the drum is on the right side of the HUMMEL, the left wheel runs on whatever surface – sanded or not yet sanded – the left side of the HUMMEL passes
over. Forward and backward.

By sanding left to right across the field of the room, all wheels of the HUMMEL will run on the same sanded surface. The machine will be level and you’ll
get optimal flatness as a result, avoiding waves. This benefit carries out in a domino effect for each sanding step in the process.

The exception to the rule is in tight or awkward spaces where common sense tells you to throw a change-up.

Big Machine Sanding Angle

If you sand with the direction of straight-laid floor boards, you are maintaining what has happened to that floor over time. You’re giving it a new look,
no doubt. But the flatness …

When you sand at an angle, you are:

Cutting across imperfections from floor movement, damage and neglect
Avoiding the vibration of loose boards that cause chatter
Avoiding waves rolling down the length of the boards

Until recently, Lägler recommended in its sanding manual to sand at an angle except for the final pass.

When sanding at an angle, at first, the scratch pattern will be more noticeable than when you cut with the direction of the floor boards. But as you sand
with increasingly finer grits and, especially, if you use a quality multi-disc sander in the process, you will remove those scratches.

Lägler now recommends to sand at an angle for all passes with the big machine.

The exception to this rule is when dealing with cupped boards of a straight-laid floor. On the first run across the floor, knock those
edges down with a head-on attack. Then go to sanding at a slight angle.

Adjusting Big Machine Sanding Pressure

Sanding pressures with the big machine are tied to abrasive grits. The finer the grit, the less drum pressure you should use.

The wood species matters, too. Softer woods should be sanded with less pressure, so not to cut too deeply into the floor.

The chart above, from Lägler’s “Sanding of Wooden Floors” manual, lays out grits related to pressure settings. Clear cut. Common sense.

When you have an extra-rough floor or one that’s damaged or coated with a hundred years of nasty, get mean with that first run. If you’re using 16 grit,
you know it makes sense to put on the coarse drum pressure to make the most of it.

Big Machine Walking Speed

To minimize sanding marks and save time in the process, pace yourself. Not too fast, not too slow. No matter how many years you have at the lever, this
relationship has to move at a steady pace. Keep in mind the grit and drum pressure. Overall, consistency is king.

For softer species, a little quicker walking speed will keep you from cutting too deeply into the floor. Or maybe it’s just that you need a slower speed
for harder species. You’re the pro on the job. If you’re getting worse scratches than you want, change the music you’re groovin’ to and adjust your
dance moves.

Learn more about the fine details of floor sanding craftsmanship. Participate in Lägler’s one-day Premium Sanding Technology (PST^®) certification course.

And download the Lägler “Sanding of Wooden Floors” manual online. It’s free.

Tag Archive for: Contractor Education

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