Turning a food can lid into springy steel?

Sorry if this is a little off the topic of actual real life cars. I’m making some home made toy cars for Christmas gifts, and – for reasons too difficult to explain - I need a bunch of round circular metal disks about 2.5 inches in diameter made of springy-type metal. Metal that won’t bend easily in other words, just spring back into the original flat shape. I can buy some springy-steel 22 gauge in sheet form which would work, but then I’d have to cut it into circles. I noticed the lids on certain food cans are just the right diameter, like peach cans. And they are already cut in circles, by the can opener. But they aren’t very springy. When bent they stay bent. I was wondering if there is a simple heat treatment I could do to them to make them more springy? I was thinking maybe heating them directly on a gas burner for 15 minutes, then plunging them into ice water?

You’re going to need to (1) have the correct steel, (2) bake the steel for controlled extended times (3) at controlled temperatures… extremely high temperatures, well beyond what your gas burner will get the material to.

In short, you won’t be able to make can tops into springs. Even if you have spring steel raw stock, you cannot make it into a spring with the temperatures and equipment you have at home.

Perhaps this link will be enlightening. If not, try looking up some websites on processes for creating spring steel. They’ll be revealing.

You don’t think a methane flame will produce 1600 deg F? When I did a little experiment the other day, it gets the metal glowing reddish-white. I thought white-hot for metals was around 2500 deg F.

It’s not the mettalurgy; it’s the geometry.

You could make a soup can into a spring by (a) cutting a long, narrow strip (a leaf spring), or a decreasing-radius spiral, stretched into a helix (a coil spring). I don’t know how you’d make one into a torsion bar…and that’s all the springs I know of that are solely dependent on metal flexure.

Try it. Let me know how you make out.

Used to make soup and beer cans too. Just made out of sheet metal.

If I might suggest changing your approach to make life easier. I often bang my head against the wall trying to do something a certain way just because that’s the way I want to do it. You can buy all kinds of wooden wheels or even make them yourself and they are fairly cheap. Otherwise I think you have to take a couple covers sandwiched together with something more substantial in the middle to give you the support you need. Or why not just big fender washers or something?

I could be wrong but the carbon content of tinplate used in food cans is too low to make it into a spring. It’s mild steel by design to facilitate the can forming and sealing process. You’d have to carburize the metal first to increase the carbon content before heat treating it to achieve the right balance of hardness. It would be easier to start with spring steel sheet and cut out the circles…

I assume the opener is the type which removes lids without leaving a sharp edge. Since that essentially means the wheel can be a thick as the edge of the lid why mess with something so thin?

Why not use a sheet of 1/16 or 1/8 aluminum? It’s very easy to work and will polish up very nicely.

An aluminum spring? That’s a new one on me! :smiley:

Yeah, even Cessna uses tubular steel leaf springs…in an airplane made out of aluminum. Flexure really isn’t what Aluminum does well…

Aluminum cannot be treated in any way that will give it spring characteristics any more than lead can be turned into gold.

For that matter, neither can mild steel. The attached link provides a good summary primer, but does not go into creating the structures within the steel that make it springy… the “heat treating”.

Detailed metallurgy can be obtained from ASME standards organization, but it’ll take some research. Years ago, back in BC (Before Computers) I had all the ASME standards in a company library, but no more.

I was under the impression the discs are going to be used for wheels; ergo, the use of aluminum.

I don’t understand why a wheel would need to be made of spring steel other than resistance to bending and staying bent.

Maybe some clarification about what part of the car these discs are going to be would help.
Other than that, I agree that aluminum or any kind of low grade steel such as used on produce cans will not ever be feasible.

I was thinking maybe heating them directly on a gas burner for 15 minutes, then plunging them into ice water?

Get the lid to red hot and this might work.

If you heat aluminum to red hot, it’ll melt. Same as your hard drive platter.

All interesting posts, thanks. Did some experiments. I heated a lid for 10 minutes in a methane flame to orange-ish-white hot, plunged it into ice water, and the result was definitely more stiff than before. I wouldn’t call it a great spring, but it was definitely more resistant to bending, more “springy” – if that’s a word … lol … I think this could work but probably better if the metal was thicker to begin with. Maybe I can double up on the lids.

Next I tried the same thing with a paper clip. Paper clips must be made out of some other kind of metal, b/c it definitely got less springy after the heat treatment. Post heat it became easier to bend. Definitely no spring-like action with heat treated paper clips.

One thing I did notice about paper clips, while the heat wasn’t effective, if I bend them repeatedly they become more stiff and springy. Still not great springs though. But a clear improvement. I presume they get work hardened. I was thinking of applying this technique to the can lid by whacking it with a hammer. Haven’t tried that yet though. Even if it do4esn’t work, a good way to rid oneself of extra aggression … lol .

I think the idea of using higher quality carbon steel sheets, a little thicker than can lids besides being more springy, that’s probably the best practical solution. Then just cut them into circles.

I’m not using the lids as wheels. It’s for the steering wheel. I want to have two lids, slightly bowl shaped, opposed to each other, then when you press on the center it makes a clicking sound but returns to its original shape. Like those clickers used in kids games. For the horn effect.

Isn’t our esteemed poster here , @Yosemite , a blacksmith? Maybe he has some ideas on this.

Steel cans are made from low carbon steel. If you heat them, they will be come soft. They are springy because the steel was cold rolled to form the tin plated sheet the cans are made of. I would expect that only acidic fool products would be in steel food cans. Tomato products are in galvanized steel cans for this reason. Aluminum cans are also low alloy metals to make them malleable. Heat treating won’t help then either.

George, Have you considered lids from jars that are vacuum packed? Seems to me I remember some of these lids are a bit concave and when you open the jar the center of the lid pops up (to assure the consumer that the container has not lost its seal). Then the lid has a tink-tink kind of “oil can” action when the center is pressed.

It’s been a while, but I’m thinking maybe baby food jars or am I just imagining the whole thing?
Do I remember the lid being “embossed” with a raised spot in the center?

Using a food can lid for a steering wheel on a toy car just does not sound like a good idea. Recycle the lids and go to a hobby shop and get parts made for the purpose.

“Recycle the lids and go to a hobby shop and get parts made for the purpose.”
Anybody can do that! He could just go to a toy store and buy the toy vehicles, too.
George is enjoying being creative!

I like CSA’s bottle top idea. Me, I’d go a bike shop and adapt some kind of bike noise maker (bell, horn, etc) for this.