When selecting a garbage disposal, is it generally best to select galvanized steel or stainless steel for the grind components (cutting blades)?

Obviously, it depends on the specific grades of steel being used, but those details are hard to come by (so far, impossible to find) for each different disposal. And I'm hoping that there are some standards used by most major brands.

Which is generally considered superior for garbage disposal grind components, galvanized steel or stainless steel?


Which is generally considered superior for garbage disposal grind components, galvanized steel or stainless steel?

As noted in the other answer, the manufacturer warranty is probably a much better indicator of quality than anything else. There are many variables that affect durability, even just of the cutting blades, never mind the rest of the appliance, so it's not likely to be useful to look just as the composition of the blades.

That said, all else being equal I would expect stainless steel to be superior to galvanized. The latter involves a sacrificial layer of zinc protecting the underlying steel. When this layer is compromised, initially the zinc near the damage will corrode preferentially, protecting the steel, but eventually the nearby zinc will be consumed and the steel itself will begin to corrode.

On the other hand, stainless steel is inherently corrosion-resistant (nearly corrosion-proof). It has a thin layer of oxide, but if that layer is damaged, instead of it exposing underlying steel to corrosion, the steel itself will reform the protective oxide layer. The efficacy of this process depends on the quality of the stainless steel, but it is in general a much more reliable protective effect than galvanization because it naturally "heals" itself, rather than naturally degrading over time.

Note, however, that with both types of materials there are different grades of steel that can be used, different grades of processing to make the final product, and different degrees of tolerances and quality-control. It's possible to make a very high-quality galvanized steel product and a very low-quality stainless steel product. Even when all the other variables are controlled for and equal, without knowing exactly the quality of the galvanized and stainless steel in each product you're comparing, you can't say whether one is necessarily better than the other.

Which again brings us back to the manufacturer warranty, the closest thing to a reliable indicator of quality.

  • Although I agree with you regarding warranties, disposal warranties are almost all so short that they really only cover initial failure. After a month, if it works, it works. Since a good garbage disposal should last over 15 years, and I've never seen a warranty come close to that (there's probably an exception somewhere), after the first few weeks the warranty is rather meaningless. I doubt they get many claims beyond 1 month. As an aside, warranty length is one (of several) reasons why I no longer buy Amazon-branded electronics: They usually only last 1 year, which is meager for electronics. – RockPaperLz- Mask it or Casket Jun 14 at 8:59
  • @RockPaperLz-MaskitorCasket: "a good garbage disposal should last over 15 years, and I've never seen a warranty come close to that" -- I don't know what you consider "close to that", but the Insinkerator models all have warranties in line with their expected lifetimes, and they include in-home repair. In any case, whether a warranty is actually equal to the expected lifetime or not, higher-quality products have longer warranties, and those warranties do provide a much better indicator as to quality than the question of galvanized vs. stainless. – Peter Duniho Jun 14 at 16:19

If you are buying just one or two (or probably anything up to a pallet full), you really don't get to pick this kind of spec. The specs you will generally get to choose (by picking different models) are:

  • Power - Typically advertised in horsepower (e.g., 1/2 HP, 1/3 HP) but more properly measured here in Amps (current) or Watts (power), which should be discoverable within the specs.
  • Warranty - A longer warranty will typically represent a better quality of components, because it costs a lot for companies to replace equipment under warranty, especially if they include on-site service (and some of them do).

There are some others - e.g., chamber size, grinding speed, and yes probably in some cases what type of blades. But some of these things will be correlated - e.g., larger chamber is likely to go with more power, and in general most people won't pick based on that level of detail, because it doesn't matter much.

Back to galvanized steel vs. stainless steel: What matters is that the blades are fast and sharp and don't rust. Which will do better? Hard to say. But my hunch is that either one can be used to produce blades that will last longer than the motor (which can wear out, like any motorized appliance, and especially in a disposal because of all the short runs), gaskets (which can wear out and leak), plastic parts (which can crack and leak), etc.

  • Thanks. "Stainless steel grind components" and/or "stainless steel grind chamber" are big marketing features touted for some models. Could just be marketing B.S., or a real difference... hence my question. – RockPaperLz- Mask it or Casket Jun 14 at 2:32
  • I suspect marketing B.S. Especially the grind chamber - who cares if it gets a little stained and isn't shiny, as long as it doesn't rust out? Might make some difference for the blades - you want them to be extremely hard, and stainless is generally a harder grade of steel than galvanized. – manassehkatz-Moving 2 Codidact Jun 14 at 2:34
  • I wonder if a stainless steel chamber would have prevented the mess in the kitchen caused by the existing non-stainless steel one failing. Haven't removed it yet, so not sure if the chamber failed or a gasket, but it's quite a nasty mess from all the drain water that flooded under the sink. – RockPaperLz- Mask it or Casket Jun 14 at 2:39
  • Hard to say without looking at it. But my hunch is that most of the time the weak spot is not the chamber itself but the gaskets/connections/pipes/etc. leading in and out of it. And a half-decent disposal should last a long time. I had one from before I redid my kitchen, and added a second one (two sinks when I redid my kitchen) and the newer one is still going strong after ~ 20 years and the older one started leaking (and I replaced it with the same model - standard Badger 5) a few years ago when it was probably at least 20 years old. I could spend twice as much (or more) on a bigger – manassehkatz-Moving 2 Codidact Jun 14 at 2:44
  • fancier disposal, but I don't think it would make much difference in useful lifetime. But hard to say - depends on how much you use it, what you put through it, etc. – manassehkatz-Moving 2 Codidact Jun 14 at 2:45

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