Imagine this scene: you’re working on making a series of cabinet doors. They all seem to be coming out of the wide belt sander with raised lines. You check your belts and realize they’ve been loading very quickly lately, and there seems to be a lot of dust around. What could be causing this? You wrack your brain… and then walk over to the machine, touch it, and ZAP! The static electricity that has built up shocks you. These are just a few of the issues that can occur when your wide belt sander is not properly grounded.
What’s going on with the static and the sander?
We’ve all been there… it’s winter. The air is dry. The heat is running. We walk across the carpet in our socks and touch a doorknob. ZAP! Ah! There it is, the static shock.
This is essentially what happens inside the wide belt sander. The static electricity, or the imbalance of electric charges within or on the surface of a material, builds up from the friction produced during sanding, as well as from when the conveyor rubs across the metal bed plates. In a similar way to when your hair stands on end from static charge, the dust particles that are created from sanding stick to the work piece, the belt and all over inside of the machine, rather than being sent through the dust extraction system. With the heat inside of the machine and excess dust, the sanding belt can become loaded and gummy, very quickly. Additionally, the dust on the workpiece tends to get caught in the cross-grains, meaning, your sanding has become that much less efficient – as cross-grain sanding can already be a challenge to do well.
The Telltale Signs of Static Issues
If you’re not sure whether your wide belt sanding issues are due to static, here are the main issues that you could indicate this issue.
Issues with the Machine & Belt:
- Sanding dust everywhere (especially vertical surfaces): If you have sanding dust inside the sander – stuck to the machine, stuck to the sanding belt, stuck to the work piece, stuck to the rollers, the platen and all the other internal components of the machine, including the tracking eyes … you likely have a static issue.
- Conveyor issues: When dust sticks to the conveyor, the pores of the rubber accumulate dust, causing your conveyor to become slippery prematurely.
- Off-tracking of the belt: Dust inside the machine leads to build up on tracking eyes, causing belts to mis-track and potentially break.
- Dust Extraction System Clogged: The dust that is collected will also have a static charge, which will cause a build up inside the dust collection system.
- Burned Belts: If dust is sticking to the work piece and the sanding belt, then you’re sanding dust with dust, which will lead to burns.
Issues on the Workpiece:
- Raised lines on the work piece: Static raised lines generally skip spots instead of being a continuous line that goes from one end of the work piece to the other; they resemble a raised “dashed line.”
- Shiny line on the length of the workpiece: Sometimes static can cause a shiny line on the workpiece that follows the oscillation of the belt.
- Cross-grain sanding is harder than usual: it could be due to excess dust building up on the grains, due to static charge.
The Solution: Grounding Your Machine
In order to dissipate the static charge that is built up, we need to “ground” the machine. This means, connecting the machine to the ground, literally, the earth, using a rod – or electrode – preferably made of copper, though any metal will do. Grounding works to remove excess static by moving electrons between the charged object and the earth. No more electrons – no more static charge! Great, so, how do we do this on the wide belt sander?
First, you will need to get your grounding rod – as previously stated, preferably made of copper – and then, you will need to attach it to the sander and drive it into the ground, beneath the concrete floor.
How to ground the sander
Part 1: Attaching the Grounding Rod to the Sander
Using a copper wire which is at least 3/8” thick, attach the rod to the metal conveyor bed of the sander, preferably on the side of the machine closest to the platen, if you have one. Remember to attach the wire from the grounding rod to the bed of the machine; this will only be a few inches away from the rubber conveyor on the side. The difference between attaching the wire to the bed instead of a plate on the frame of the machine is significant.
Tips for optimal results:
- DO: Make sure to attach the ground wire to the actual bed and not a plate.
- DO REMOVE PAINT: If the bed is painted, then the paint around where you attach the wire should be removed.
- DO LEAVE SLACK: Make sure to leave enough slack in the wire to allow your bed to move up and down.
- DO NOT: Attach the ground wire to the foot of the machine.
Part 2: Attaching the Grounding Rod to the Earth
Once the rod is connected to the sander, you’ll insert it through the floor and into the ground below, about 3-6 feet deep.
Tips for optimal results:
- DO: It is critical that the rod be connected to the ACTUAL, natural ground, so if fill dirt was used, you’ll need to dig a little deeper to make sure to connect to native soil.
- Dry soil? Go deeper into the ground.
- VERY dry soil? Try pouring some water around the grounding rod.
Part 3: Still having static issues?
If static is still an issue, hanging tinsel over the belts and running another wire to the grounding rod will help.
Conclusion
Static charge on your wide belt sander can wreak havoc on your machine and workpiece. With static comes an excess of dust – everywhere – and very likely, burned belts, raised lines on your work piece and waisted time and money. These issues can potentially be resolved by grounding the sander into the earth using a grounding rod. Grounding the sander will cut back on wasted belts, resolve your dust collection issues and improve the quality of your sanding results. If you need advice on how to ground your sander, contact our sales technicians at sales@uneeda.com.
