does anodized rust?

Got a GSI anodized pressure cooker in the mail with the idea of using it for camping. Aluminum doesn’t rust, but it never occured to me to ask … does anodization change anything? (Will have to watch out for my stainless steel valves!)

(check out the cioppino! :slight_smile:

When it does … clean / scrub with
Simple Green … breaks it right down and doesn’t make a mess or scratch up the surface.

Correct me if I’m wrong
but I do not believe an anodized coat can ‘rust’. I’ve never seen anodized carabiners ‘rust’ (except for the stainless springs over time) when used on a dog line left outside for 14 years. And I’ve never seen anodized aluminum gunwales on any canoe be affected after likewise years of outside storage, unprotected.

anodization’s main purpose in life is to provide improved corrosion resistance to aluminum.


Its a coating created by a chemical reaction…essentially a protective patina. If it is scratched through to the aluminum, the underlying metal will begin to deteriorate. Aluminum oxidizes white.

Of course, you can find lots of old aluminum pots at the garage sale with no protection. They seem to hold up pretty well.

Hard Vs Soft anodizing
Two very different things. A hard anodized Al alloy will be pretty tough to scratch, and very resistant to corrosion from salt water. Soft anodizing will scratch easy, UV degrade, and you will see corrosion as it wears.

Titanium cookwear, etc. is awesome around salt water. I us Ti for that reason. Also have two very rare Ti carabiners that look brand new after 20 years of sakt water use and no rinsing ever.

Stainless comes in many grades and the good stuff is very resistant to corrosion, the cheap stuff…not so great.

Stainless Steel really isn’t always stainless

Actually it isn’t really how “Good” it is that determines weather it will rust or not but how much carbon the alloy contains. In fact, a good stainless knife will rust in not taken care of.


Not rust, but some kind of degradation
I had an anodized aluminum bike rack years ago. That bike got used in salty slush during New England winter training rides. Even though I frequently washed it in the shower right after riding, I didn’t always do so. After a while it developed some dark blobby discolorations.

Anodizing, or anodising, is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. On many other metals, anodizing increases corrosion resistance and wear resistance, and provides better adhesion for paint primers and glues than bare metal. Anodic films can also be used for a number of cosmetic effects, either with thick porous coatings that can absorb dyes or with thin transparent coatings that add interference effects to reflected light. Anodizing is also used to prevent galling of threaded components and to make dielectric films for electrolytic capacitors. Anodic films are most commonly applied to protect aluminium alloys, although processes also exist for titanium, zinc, magnesium, and niobium. This process is not a useful treatment for iron or carbon steel because these metals expand when oxidized. This iron oxide (also known as rust) flakes off, thus constantly exposing the underlying metal to corrosion.

Anodization changes the microscopic texture of the surface and can change the crystal structure of the metal near the surface. Coatings are often porous, even when thick, so a sealing process is often needed to achieve corrosion resistance. The process is called “anodizing” because the part to be treated forms the anode electrode of an electrical circuit, more specifically an electrochemical electrolytic process. Anodized aluminum surfaces are harder than aluminum but have low to moderate wear resistance, although this can be improved with thickness and sealing. Anodic films are generally much stronger and more adherent than most types of paint and metal plating, making them less likely to crack and peel.

corrosion… the subject of extensive
research in the aerospace, marine and structural engineering circles. Annodized aluminum will corrode if (and when) the surface is scratched, dinged, et cetera and the underlying aluminum is exposed. Depending upon the usage application, it may or may not be a concern. The corrosion itself creates a passive layer that, unless it is then compromised, is not necessarily a bad thing.

Also, one must consider the materials of related fasteners. “Galvanic corrosion” and “wet install” may be opportunities for you to google if you want to learn more. Several case studies can be found in the literature including some interesting aircraft failure reports.

As stated above, aluminum corrosion doesn’t look like rust, unless nearby materials (fasteners, …) have surface impurities (iron) that give that rust color / roughness.

It is rust
Anodization is rust in a sense.

Good hard anodized cookware is pretty tough stuff. Though hard anodized cookware is relatively new to camp cookware, it has been in the kitchen for ages.

I can’t speak for GSI’s quality, but I have an “old school” hard anodized Calphalon skillet that’s seen quite a bit of abuse. The coating is very, very hard and resists metal spatulas, etc. with ease. It’s very difficult to scratch. It’s also reasonably stick resistant. If you can cook with stainless or iron, hard anodized cookware will be no problem at all.

A word of warning though; NEVER, EVER wash it in your dishwasher. Dishwasher detergent is mildly caustic and will REMOVE THE ANODIZATION! Hopefully this nugget of info is in the owner’s manual.

I hope you report back how your GSI pressure cooker works out; I’ve been eyeballing one of those for a while now.



Will my tungsten ring corrode?
I think tungsten dose corrode, but i don’t know what to look for.

How Good Are You At Repairs ?
Kris at BMO river commutes to work in a Wenonah Advantage in UL Carbon. He has put hundreds if not thousands of miles on that boat but he ends up doing repair work on it once a year or so. Nothing major but its had a new skin coat and some s-glass added to the stems.

They do not have much UV protection and need to be stored indoors, but other than that will handle normal paddling and transport just fine.

How Good Are You At Repairs ?
Kris at BMO river commutes to work in a Wenonah Advantage in UL Carbon. He has put hundreds if not thousands of miles on that boat but he ends up doing repair work on it once a year or so. Nothing major but its had a new skin coat and some s-glass added to the stems.

They do not have much UV protection and need to be stored indoors, but other than that will handle normal paddling and transport just fine.


– Last Updated: Feb-25-08 7:19 AM EST –

we do not own a dishwasher! (or microwave :-)

Will do: I will report back to you as soon as I have anything to say. I did give it an initial "fire up" test run in the kitchen ("Everybody clear out--this could explode!"). No explosion. A little disappointed in the "rocker"--the steam regulating weight. We had one in my childhood that raised such a racket, I'll forever associate pressure cookers with that sound. But the new one, the GSI, makes hardly no noise at all. More like air escaping from a punctured tire. Alarming in how un-alarming it is.

For anyone interested, here's what I got (you have to cut and paste the entire URL):

I've seen them for as low as 50 bucks.

And I just discovered that my nesting pots and stove fit inside! Camping this year is going to be posh. :slight_smile:


– Last Updated: Feb-24-08 4:16 PM EST –

Actually, you've reached the perfect balance if the release valve just barely hisses. If it's screaming, you're just wasting energy and depleting the water reserve. That's why the pressure cooker can be so efficient; higher pressure means the steam inside can be higher than 212 degrees and little or no steam escaping means less energy loss. Since you're cooking with high(er) pressure steam instead of boiling water, there's less water to heat and therefore less fuel to use as well.

Rice, beans and pasta cook super fast in a pressure cooker and meat can go from frozen to "fall off the bone" in less than 20 minutes. I'd google "pressure cooker basics" and spend some time reading before going crazy with your new gadget if you've never used one before.


P.S. This will probably never come into play with your pressure cooker, but never use a product like "Pam" on hard anodized cookware. Non stick sprays get in into the pores and leave a weird residue you'll never get off. Use regular oil and preferably add it after the cookware has been heated up some.

thanks for the tips!
no to pam, yes to spam