# How in Gods name do they make memory metal?? **URL:** \ **Category:** Factual Questions\ **Created:** [June 16, 2002, 2:19pm UTC](https://boards.straightdope.com/t/how-in-gods-name-do-they-make-memory-metal/114360 "2002-06-16T14:19:05Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Jukeball](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@Jukeball](https://boards.straightdope.com/u/Jukeball)\ **Post date:** [June 16, 2002, 2:19pm UTC](https://boards.straightdope.com/t/how-in-gods-name-do-they-make-memory-metal/114360/1 "2002-06-16T14:19:05Z")
OK , so I was seeing this program on Discovery and this guy is showing of something he or his company or someone made. It looked like a spring at the start and then he twisted in ten different ways . He took what looked like a hair blower , directed on the metal and Vola! the had been spring reatined its original form and really , and I mean really twisted the spring . He also talked about compressing building and magically making them grow on the spot using this memory metal. What a dude!!! ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [June 16, 2002, 2:43pm UTC](https://boards.straightdope.com/t/how-in-gods-name-do-they-make-memory-metal/114360/2 "2002-06-16T14:43:18Z")
Funny you should ask. I was just reading about this in a book by Martin Gardner. It’s an alloy of nickel and titanium called nitinol. I found this page about it: [http://www.grand-illusions.com/spoon/nitinol.htm](http://www.grand-illusions.com/spoon/nitinol.htm) ---
**Author:** ![Mr.Blue\_Sky](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@Mr.Blue\_Sky](https://boards.straightdope.com/u/Mr.Blue_Sky)\ **Post date:** [June 16, 2002, 2:46pm UTC](https://boards.straightdope.com/t/how-in-gods-name-do-they-make-memory-metal/114360/3 "2002-06-16T14:46:36Z")
Also, there’s [this page of links](http://www.sma-inc.com/information.html) ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [June 16, 2002, 5:09pm UTC](https://boards.straightdope.com/t/how-in-gods-name-do-they-make-memory-metal/114360/4 "2002-06-16T17:09:24Z")
Has anyone sucessfully made car fenders out of this stuff? ---
**Author:** ![ianzin](https://avatars.discourse-cdn.com/v4/letter/i/ed655f/32.png) [@ianzin](https://boards.straightdope.com/u/ianzin)\ **Post date:** [June 16, 2002, 6:04pm UTC](https://boards.straightdope.com/t/how-in-gods-name-do-they-make-memory-metal/114360/5 "2002-06-16T18:04:37Z")
I have a Nitinol teaspoon which is good fun. It’s ‘natural’ shape is bent upwards, almost double, but under cold water and at room tempo I can straighten it out. When anyone uses the spoon to stir a hot liquid such as tea or coffee, it instantly bends upwards so the bowl is almost touching the stem. This freaks people out! What I never realised before I actually owned one of these spoons is how quickly this reaction occurs. It can happen in less than half a second. It all depends on the temperature of whatever it is dunked into. **Enola Straight** the answer is no. Nitinol is a very soft alloy. A child can bend and twist it with his hands. Not much good for a fender. And it would only ‘revert’ to its original shape when subjected to an appropriate temperature. ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [June 17, 2002, 1:26am UTC](https://boards.straightdope.com/t/how-in-gods-name-do-they-make-memory-metal/114360/6 "2002-06-17T01:26:19Z")
> [@](#): > > \*Originally posted by Enola Straight \* > \*\*Has anyone sucessfully made car fenders out of this stuff? \*\* No, for a couple of reasons (besides the one **ianzin** mentioned: 1.) Titanium ain’t cheap. While I’m not sure of the ratio of titanium to nickel in nitinol, you’d still need lots of it if you were going to do mass production of car parts. 2.) Nickel ain’t cheap either. 3.) Steel is _very_ cheap. A couple of years ago I took a car to a scrap yard and the guy running the place told me that scrap prices for steel were so low that it wasn’t worth hauling the cars off to be melted down any more. 4.) I don’t know about nitinol, but I do know that titanium is a pain to weld. You can’t weld it in an oxygen atmosphere, it has to be done in an inert one or bad things happen. It stands to reason that the same is prolly true of nitinol. Imagine trying to patch weld a car made out of nitinol. If you couldn’t get the particular part off the car, you’d have to put the whole car in a sealed room, pump all the air out and replace it with something like argon (not cheap), and have either a robot weld it (not cheap and time consuming to program) or send in a guy in a “spacesuit” to weld it. 5.) Even if it were practical to build cars out of the stuff, they’d never do it. Too many body shops and parts manufacturers would go out of business. ---
**Author:** ![donkeyoatey](https://avatars.discourse-cdn.com/v4/letter/d/e47c2d/32.png) [@donkeyoatey](https://boards.straightdope.com/u/donkeyoatey)\ **Post date:** [June 17, 2002, 3:39am UTC](https://boards.straightdope.com/t/how-in-gods-name-do-they-make-memory-metal/114360/7 "2002-06-17T03:39:19Z")
> [@](#): > > \*Originally posted by Tuckerfan \* > \*\* If you couldn’t get the particular part off the car, you’d have to put the whole car in a sealed room, pump all the air out and replace it with something like argon (not cheap), and have either a robot weld it (not cheap and time consuming to program) or send in a guy in a “spacesuit” to weld it. > > \*\* Why wouldn’t a TIG welder work? ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [June 17, 2002, 3:57am UTC](https://boards.straightdope.com/t/how-in-gods-name-do-they-make-memory-metal/114360/8 "2002-06-17T03:57:53Z")
> [@](#): > > \*Originally posted by donkeyoatey \* > \*\* > > Why wouldn’t a TIG welder work? \*\* IANAW (I Am Not A Welder), but I believe its the atmospheric oxygen that prevents the metal from joining together when its welded.