A drum and belt sander uses an abrasive belt to sand the floor. Replacing this belt usually requires opening a drum access panel, then inserting the belt and closing the access panel. Operating a such a device requires a bit of practice beforehand in order to get a good feel for the device and how it behaves. As previously suggested, it is strongly recommended that you test the machine on a plywood board before tackling a floor, to avoid unpleasant surprises and damaging your floor before you even sand it.
To operate this sander, make sure the drum is not in contact with the floor (the sander usually has a lever or mechanism that allows the drum to be raised and lowered). Then, make sure that the device is turned off, plug it into an electrical outlet, and before turning it on, make sure that the power cord is not in the path of the machine. You are now ready to sand! When sanding with a drum and belt sander, it's important to always sand in the direction of the grain of the wood (except during the first sanding or when it comes to determining the starting grain, as explained below). Begin pushing the sander in front of you while gently lowering the drum to the floor. As you approach the wall, you'll want to raise the drum before stopping. Once the drum has been raised and the device is at the end of its path, you'll sand the same surface again, but this time by moving backwards. Again, you will lower the drum gently as you begin to reverse and raise it before you get to your original starting point. Congratulations, you have completed your first sanding "pass", which is considered a "round trip" on the same floor area.
Once a pass is done, move the sander sideways, with the drum raised, without moving the appliance more than half the width of the belt or the drum, and proceed in the same way until the the entire surface is sanded. It is important to overlap each "pass", and to never stop moving the sander forward or backward when the drum is in contact with the floor, otherwise you will leave sand marks on the floor which may be difficult to remove, as excess material will have been removed.
Belt and drum sanders require a special sanding procedure. The first sanding phase should be done at a minimum of a 7 to 15 degree angle to the length of the boards, so as to allow the floor to be flattened / leveled. In cases where a floor has moved a lot over time, or in cases where the floor is made up of very wide boards, a much more aggressive angle (up to 45 degrees) may be used to succeed in putting the floor back to level. The more uneven the floor, the steeper the angle of the first cut should be. In the event that a hardwood floor has curved/warped boards, the sander should be used by following the wood grain during the first sanding, and then sand again, this time at an angle varying between 7 and 15 degrees.
Finally, if the first sanding is done at an angle greater than 15 degrees to the length of the boards, the next sanding must be done with the same grit, but at an angle opposite to the previous sanding, in order to remove the sanding marks and level the floor properly. If the starting angle of the first sanding is less than 15 degrees, the second sanding phase should be done with the next grit, again in the opposite angle as the previous sanding, so as to remove the sanding marks. Each successive step should be carried out following the length of the boards (following wood grain), and aim to remove the sanding marks caused by the previous sanding. If the result is not satisfactory, repeat the previous step.
Depending on the type of floor and its previous finish, you can expect a drum and belt sander to sand an area of about 100 to 400 square feet before the sandpaper belt needs to be replaced. Remember to empty the dust collection bag regularly throughout the sanding process.
Travel speed when using a drum and belt sander should be slow and constant. Coarser or harsh abrasives usually require a slower speed than finer abrasives.
Parquet floors, marquetry, and end-grain wood flooring
Note that this way of sanding a hardwood floor using a belt sander does not apply to parquet and end-grain floors, which require a different approach. These should usually be sanded at a 45 degree angle to the grain of the wood, followed by the opposite angle in the next step, and so on. If in doubt, or for another type of flooring such as cork or bamboo, contact your flooring professional before starting a sanding project.
Operating an orbital / vibrating plate sander
The orbital or vibrating plate sander is much easier to operate than a drum and belt sander and is ideal for sanding floors in good or medium condition. Some models even allow you to sand the edge of the walls without damaging the moldings, as well as more confined spaces, eliminating the need to rent an edger to sand these areas. If in doubt, ask your equipment rental center professionals when you're ready to begin your project.
The first thing to do before sanding is to attach the sandpaper to its base. First make sure that the sander is not plugged into an electrical outlet and that it is turned off. Gently lay the device on its back to gain access to the underside of the device. You will first need to affix a stabilizing foam pad to the sanding plate, then affix a sheet of sandpaper (usually 12 X 18 inches, but your experience may differ), the abrasive part facing out. With the sanding sheet in place, raise the unit to an upright position. On some models, all you have to do is put on the foam pad and then place the device on top of the sheet of abrasive paper that has been placed on the floor. You can then plug in the device and refer to the manufacturer's instructions to familiarize yourself with the controls. Most of these devices have an adjustable handle that must be unlocked to allow you to operate the tool in a comfortable position. Make sure the power cord is out of the way. You're now ready to sand!
You can now turn on the sander. Keep in mind that since this is a random orbital sander, it performs random sanding patterns. Therefore, there is no need to sand following the direction of the wood grain, as opposed to using a drum and belt sander. You can sand in any direction, letting the machine do all the work. Make sure, however, to always keep the unit moving when it is running, to prevent the sandpaper from getting clogged with dust or old finish.
Depending on the type of floor and its previous finish, you can expect a vibrating plate sander or orbital sander to sand an area of 100 to 400 square feet before the sandpaper belt needs to be replaced. Remember to empty the dust collection bag regularly throughout the sanding process.
Operating an edger
To sand along walls or in tight spaces where the aforementioned machines cannot reach, the edger is your tool of choice. It's a tool with a relatively simple design, but its power can be daunting at first. Before connecting this machine, put on the appropriate abrasive disc. Most edgers use a mechanism allowing the abrasive disc it to be affixed with a nut, which must not be over-tightened. Your device might have a different mechanism, so check with the equipment rental shop beforehand.
To operate the edger, first make sure that the machine's power switch is OFF before plugging in the power cord. Then tilt the appliance so that the sandpaper is not in contact with the floor. You can now start using the sander by gently lowering it to the floor to begin sanding. The abrasive disc on this machine rotates clockwise. For this reason, you'll want to sand from left to right, since this is the direction in which the sander will naturally move. An edger is a fairly powerful and aggressive device: Therefore, it's not necessary (neither advisable) to lean on it and put some weight on it to "help" with the sanding process. Just let the device work by itself. Adding additional weight or pressure to this type of sander risks damaging the unit in addition to leaving nasty sand marks on the floor.
Sand over an area of 1 to 2 square feet at a time, moving the sander back and forth in a Z pattern, getting a little closer to the wall with each pass. It is also important to overlap the sanding passes and to blend in the areas previously sanded with the sanding machine used on the rest of the floor to ensure a uniform finish. Note that you must always use the same type of sandpaper on the edger as on the sanding machine that you used on the rest of the floor during the previous step. The edger should always follow the same grit progression as the drum and belt or orbital sander. For this reason, you should always determine the perimeter of the room with pencil marks in order to properly assess your progress and make sure that you have sanded everything. It is sometimes difficult to maintain a consistent sanding pattern and cover everything, and it is not always easy to identify certain areas of the surface that have not been sanded.
Depending on the type of floor and its previous finish, you can expect an edger to sand an area of 10 to 40 square feet before the abrasive disc will need to be replaced. Remember to empty the dust collection bag regularly throughout the sanding process.
A warning to woodworkers: You'll want to sand the contours of the part using your belt sander, but even the largest and most powerful belt sander cannot do the job as efficiently as it does. 'a contour sandblaster. In short, sanding the edges of the walls with a belt sander is the equivalent of digging a well with a trowel: it is possible to do it, but be patient! You will also want to polish the furrows and sand marks using an orbital sander, but be warned: these sanders can overpolish the wood so that the finish does not give the same effect on those overpolished surfaces. Sandblasting flaws by hand is much slower, but avoids this kind of complication.
The polisher / buffer: an optional step to finish like the pros or to eliminate the remaining defects.
At this stage, it is important to use a buffer equipped with a pad / screen in order to remove the remaining sand marks. Using such a tool will even out the surface between the surface sanded with the contour sandblaster and the one treated with a roller / drum / belt sandblaster, and polish the scratches. This step can be done using a polisher / buffer or using a sanding pole (same as for sanding drywall). We recommend that sometimes on oiling errors, but for preparation sanding it's p-e too much). In all cases, the abrasive to use is 100-120 grit depending on the type of finish that will be used in the end. It is this step that makes the difference between an “amateur” floor and a “professional” floor. Expect the buffer to swing left or right depending on how you position the grip of the device, buffering large arches along the floor for a smooth surface.
The annoying corners!
There are a few spots that even the edger won't be able to reach. In the corners of walls, around door frames, etc. you will want to use a paint scraper, using constant pressure and scraping in the direction of the wood grain. After scraping, you can use a sand block and sandpaper of the same grit as used in each sanding step with electric sanders.
Conclusion
There you go, your floor is sanded and clean, the weekend is over, your arms and back are aching, and you are half deaf (have you used the ear protectors?). but hey, you are ready to receive your world for a party, you have a great story to tell and you will really appreciate the professionals who will do the work next time!
Ardec would like to underline the collaboration of two technical experts who were of great help to us in the preparation of this series on sanding floors, namely Mr. Luc Pelletier and Ms. Sylvie Plasse. We warmly thank them for the time they gave us in preparing this article. Any technical errors in this article should not be attributed to them; this responsibility rests entirely with Ardec.
