Garbage Disposal Blades: How to Sharpen, Fix or Replace Them


A garbage disposal is a helpful household appliance when it is working properly. At some point in time, your garbage disposal in your kitchen sink is going to need some proper maintenance. Garbage disposal blades are one of the parts needed to be maintained. The difficulty for most people who have a garbage disposal in their kitchen is separating fact from fiction when it comes to keeping your garbage disposal in good working order. There are so many maintenance myths about garbage disposal circulating around the internet. To make this necessary chore less of a risky proposition, here are tips to help keep your disposal in peak operating condition.

Do the blades in my garbage disposal require sharpening?

Short answer? No. The “blades” in your garbage disposal aren’t quite the high RPM whirling razors of destruction. What most people call blades in a garbage disposal are actually riveted stationary impellers that are fixed in place while a rotating plate spins the debris past them in order to chew it up into drain friendly bits and pieces. The impellers are high grade stainless steel. They do not require any sort of regular sharpening in order to keep your disposal working correctly and efficiently.

There are a number of “old plumber’s tales” that involve throwing eggshells, walnut hulls, or coffee grounds down a disposal in order to “sharpen up” the impellers or blades. All of these “remedies” are complete and utter bunk. High-carbon stainless steel at high speed is far too hard-edged to be shaped or worn down by something as fragile as eggshells or ground up beans. Walnut hulls are also more likely to jam between the impeller plate and the sidewalls of the disposal chamber than they are to in anyway alter the state of the impeller blade. If anything, you are most likely going to burn out your motor before you affect the sharpness or dullness of the impellers.

Related: How do you unclog a garbage disposal


How do I tell if the impellers in my garbage disposal are loose?

It may sound somewhat unhelpful to say “Oh…you’ll know”, but the sound of loose impellers is very distinctive. It is the sound of something metallic attempting to tear itself apart via continuously escalating vibrations, usually accompanied by the sound of shrieking metal.

If you are keen to make sure your impellers are secure and stable, there are steps you can take to assure that your garbage disposal isn’t ready to self-destruct. Start by disconnecting your disposal from power. Check it with the activation switch to verify its off before sticking your hand anywhere near the impellers. Check twice, and keep your fingers. Get your work gloves on next, and try to rotate the impeller plate by hand.

As you move the plate, the impellers should slide freely back and forth along their rivets. However, there should be no vertical movement of any kind. If you can lift the impellers up from the rotating plate, the impellers are coming loose and may need repair.

Also, check to see if any food or waste is trapped in the impellers, or between the disposal chamber wall and the impeller plate itself. These are the two areas most likely to trap solid waste and cause a jam or impede the proper function of the impellers or impeller plate.


How do I go about repairing loose blades in a garbage disposal?

Impeller repair is not recommended for the average user as a general rule. When impellers become loosened due to excessive wear or from being overloaded during use, it is often safer and less expensive (not to mention significantly easier) to simply replace the garbage disposal entirely.

Loose rivets or impellers in a garbage disposal are generally a sign that a disposal is on its last legs. It is especially when you hear them making their signature “wood-screws-passing-through-a-jet-engine” death rattle. If you are handy with tools and know something about breaking down and repairing things on your own, you might try tightening your impellers back up. However, this requires degree of skill that is beyond even the most intrepid of DIYers. Therefore, it is best left to repair and maintenance professionals.


How do I prevent the blades from becoming dull or jammed?

You avoid putting fibrous vegetables down your drain because they tend to tangle around the disposal’s blades. These vegetables include artichoke, celery, rhubarb, lettuce, kale, cornhusks, onion skins, asparagus, and chard. Learn more about things you should not put down your garbage disposal.

Related: Garbage Disposal Do’s and Don’ts


Final Thoughts

Overall, garbage disposal maintenance is a matter of consistently maintaining the guiding principles for daily garbage disposal care. Don’t put all your food waste down the garbage disposal. Never feed dry onion skins or dried vegetable peelings into the disposal. Also,always run cold water from the tap when your disposal is active. Taking these simple steps ensures that your garbage disposal remains functional.

2 responses to “Garbage Disposal Blades: How to Sharpen, Fix or Replace Them

  1. […] Related: How to Sharpen, Fix or Replace a Garbage Disposal […]

  2. Annette says:

    My disposal sits idle for months. Would it be useful to spray WD40 into it while it is spinning to prevent rusting?

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