How To Use A Wood Sander On Floors

Using a belt or disk sander on hardwood floors involves renting the equipment, prepping the surface and making several passes to remove the old finish.

There are two different methods of sanding any surface- bring the project to the sander or the sander to the project. Small woodworking projects can be easily sanded with a small electric sander or with sandpaper aided by elbow grease. Hardwood floors, however, require a specialized sander which must be brought to the site. These sanders usually come in two forms- a belt sander which resembles an upright vacuum cleaner and a disk sander which resembles a floor buffer. Both machines can be rented from a local outlet or a home improvement store, along with replacement sandpaper belts or disks. It's important to treat these accessories carefully, because the rental agencies tend to charge a premium for excessive usage.

A belt sander is better for sanding floors with a definite grain and lots of exposed areas. Belt sanders follow a straight line, which means they can reach into corners better than a disk sander. If appearance of the finished floor is vitally important, a belt sander will help maintain the grain pattern. A disk sander, on the other hand, is better for covering large areas in less time. Several sanding disks work in unison to sand the area under the unit. Disk sanders cannot reach sharp corners, but a manual sander can finish the job. Because the disks spin in circles, they may not follow the grain of the wood as well as a belt sander. If the finished floor will be largely covered by an area rug or furniture, then the disk sander will finish the job faster.

The staining process may reveal the circles created by a disk sander, but it shouldn't be objectionable for most needs.

Here's how to use a belt sander to remove varnish or other treatments from hardwood floors:

1. Prep the area thoroughly. Floor sanders require a clear path in order to work at their best. This is not an operation you can perform around furniture or existing carpeting. Clear out the room completely, then examine the floor for exposed nails, adhesive residue, warped boards, heavy soiling, etc. Use a scraper to remove dirt or other residue. Either remove exposed nails or pound them deeper into the boards. Sweep the floor thoroughly before bringing in the sander. Be sure to wear a protective face mask, because a belt sander created a significant amount of dust and the onboard collection bag doesn't catch it all.

2. Plan out a route to follow. A belt sander works in one direction only, so avoid sanding yourself into a corner. Work in small sections, starting from the area farthest from the exit door.



A belt sander works much like a powered lawnmower, but is held much like a vacuum cleaner. Plug in the power, clear the cord from the area and switch on the motor. Some sanders also have a hand-operate clutch to disengage the belt. Place the sander on the first section of flooring and press the clutch to start the sanding process.

The idea is to allow the machine to do most of the work, but you must keep it moving steadily. Don't try to remove all of the varnish and stain in one pass- allow the machine to grind off a thin layer. If you don't keep a belt sander moving, the sandpaper will occasionally snag on the floor and create deep gouges. If you move too fast, the sander will not make much contact with the floor and the results will be noticeably uneven. It may take a few passes to determine a proper pace, so watch the results as the sander passes over a new section.

3. Always follow the grain of the wood, even if the floor changes directions. Some hardwood floors feature designs which change direction from time to time, so you may have to stop the machine and physically move it into a new position. Continue sanding until directions change again. One thing you cannot do under any circumstances is back up. Pulling a working belt sander backwards will cause severe damage to the floor and possibly tear up the belt itself. Replacing a belt on a sander involves several steps, so make sure you get proper instruction from the rental agency. Generally, the old belt must be released from a clamp holding it to the motor unit. One end of a new belt is secured under the clamp, then the belt is looped over a holder. The other end is then secured under the clamp and the sander should work again.

4. Sweep and/or vacuum excess dust between passes. Once a few sections have been sanded, it's a good idea to use a good broom or shop vac to clean up the dust. The project will not be done until the final cleanup, but it pays to stay ahead of the game. This is also a good time to look for trouble spots such as warped or water-damaged boards. Belt sanders tend to lose belts when passed over high spots and cracks. If you don't feel good about a particular area, don't try to sand it with a floor sander. Wait until you can use a hand-held sander or find an assistant to work on the problem areas while you continue to use the sander. Time is money, so get the most use you can out of a rented floor sander. If an area is a little uneven, tackle it later with your own sanding equipment.

5. A disk sander works basically the same way, but you may have a little more freedom of movement. Floors which change direction won't necessarily affect the work of a disk sander, but watch the results anyway. Again, this machine WANTS to do more than it really should, so you must keep it under control. Allow the machine to flow over the area, but go slowly enough to get as much of the varnish and stain removed as possible. If you pace yourself properly, a disk sander shouldn't leave heavy circles. The only thing a disk sander can't do is reach sharp corners. You can get very close to the edges, but the corners will have to be sanded by hand for best results.

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