Quick answer: Clean a loaded sanding belt by holding a belt eraser – a block of soft crepe rubber – against the running belt for a few seconds. It pulls the packed dust, resin, paint and metal out of the grain without wearing the abrasive, and can extend belt life by up to 50%. Use it as soon as the belt starts to load, on any grit and any grain. To slow loading in the first place, run a grease stick on the belt before you start on metal. Replace the belt when the grain is dull rather than clogged – an eraser can't bring back a worn belt.
Loaded or worn?
A belt stops cutting for one of two reasons. It's loaded – the spaces between the grains are packed with dust, resin, finish or metal, so the grain can't reach the work – or it's worn, with grain that's dulled or gone. Loaded belts look glazed or caked and often still feel sharp at the edge where they haven't touched the work; worn belts look bald and feel smooth everywhere. Cleaning fixes the first. Only a new belt fixes the second.
| Sign | Loaded | Worn |
|---|---|---|
| Appearance | Shiny, caked, dark streaks | Bald, grain visibly rounded or missing |
| Feel | Smooth where it's caked, sharp at the edges | Smooth everywhere |
| Cut | Drops off suddenly, burns | Fades gradually |
| Fix | Belt eraser | Replace |
How to clean a sanding belt with a belt eraser
- Run the belt at normal speed. Wear eye protection – it throws the debris.
- Hold the belt eraser firmly with both hands and press it lightly against the running belt on the platen or contact wheel.
- Move it slowly across the full width of the belt. You'll see the caked material come off and the color of the grain come back.
- Five to ten seconds is usually enough. Stop when the belt looks clean; longer doesn't help.
- Do the same on discs, drum sander wraps and wide belts – hold the eraser against whatever is spinning.
The crepe rubber is soft, so it doesn't shrink the belt or wear the grain – it just grabs what's stuck between the grains and pulls it out. It works on aluminum oxide, zirconia and ceramic, in every grit, on cloth or paper. Cleaned belts cut better and leave a better finish than loaded ones, and you'll get up to 50% more life out of them – which, on a rack of belts, adds up fast.
Cleaning belts by washing
Cloth belts on a polyester or poly-cotton backing can also be washed – power-washed or scrubbed with warm water and a little detergent – to strip sap and resin out of the grain. Hang them to dry completely before use. Don't wash paper belts, and don't soak any belt's joint for long. Washing is a good reset for a badly loaded belt; the eraser is for keeping a belt clean during a job.
Stop the loading before it starts: grease sticks
When sanding metal – especially aluminum, brass and other soft, gummy metals – run a grease stick across the running belt before you start and whenever the cut fades. The thin film of lubricant keeps swarf from welding into the grain, reduces friction and heat, and makes the belt cut cooler and cleaner. Applying it to a new belt before first use is the single best thing you can do to stop loading. Grease sticks are for metal; on wood, use open-coat belts and good extraction instead.
Habits that make belts last
- Clean early. Erase the belt the moment the cut fades, not after it's burned the work.
- Match the belt to the material. Open coat on softwood and paint, closed coat on hardwood and steel – see open vs. closed coat.
- Don't press harder. Pressure loads and burns. If the belt won't cut with normal pressure, clean it or change it.
- Run extraction. Dust that's pulled away can't load the belt.
- Store belts dry, hung or flat, off the floor. Damp belts load faster and their joints fail – see why sanding belts break.
- Rotate belts. On multi-grit jobs, keep a cleaned belt of each grit ready instead of running one until it dies.
Get a belt eraser and a grease stick for the shop, or browse sanding belts.
