How Were These Aluminum Cans Made?

[polaraligned]

These were made in the 1930's and chrome plated. Very thin aluminum, just 0.018". 3.5" dia x 4.5" tall.
Just wondering about the process used to make these.

[Dan Dubeau]

deep drawing probably.

Alternatively you could roll the cylinder, and weld the cap on if you needed to make another, but I don't think that one was made that way.

[boslab]

They look like DRD (drawn redrawn) but at that stage they could equally be DWI (drawn and wall ironed), you can watch videos of both on the tube, another method is impact extrusion but the die lines are wrong, the slug splashes up the tool, I've not had a lot to do with that but have seen it, it's actually quite amazing to watch, I watched aerosol cans being made, they were really tall too.
Addendum I don't think DWI was about that far back, just DRD
Mark

[danlb]

I agree with Dan. A disc is put in a multi stage press that almost works like an extruder. The marks from the ram are the long parallel lines inside the container.

I know this because I saw it on "How it's made"

Dan

[Bmyers]

A Cincinnati hydroform could make those.

[polaraligned]

Thanks guys. I just looked up some videos of draw redrawn process.
It is amazing that a disc of metal can be stretched that far in the room temperature state and not come apart or show severe stress issues.
Equally amazing is how the open end is perfect too and doesn't have to be cut, and the sides are perfectly smooth.

I would guess that the forming die has just enough clearance for the aluminum thickness, which in this case would be less than 0.018".

I really don't need to make any, but being able to get the dents out of some of them would be nice. With the chrome plating, filler is not an option.

[old mart]

I wonder what they were made for? Plated chrome is hard and brittle, trying to remove dents could end badly.

[Rich Carlstedt]

It's a deep drawn cup . The chrome would have to be done after forming for two reasons , the hardness of chrome would play havoc on the punch and die set and the chrome is not ductile enough to withstand that much draw and not become porous .
.018 is rather thick for cans Today...you will find your beer can to be in the .004 to .005 wall thickness. When i last looked they were using .013" material to start. Made cans over 40 years ago, and can say that the quality of the material is critical whether it is aluminum or steel.
When material is deep drawn, it gets quite hot and some folks say that aluminum actually liquefies during the process.
As a side note, to get good deep drawn steel cans , we used "killed" steel. That is steel that has aluminum in it. It kills the strength of steel because of the impurity of aluminum ( which removes the grain ) and the result is a more even draw in the die . Lubrication is another imperative function and the best for steel drawing was Lanolin ( Sheep Fat). Beverage cans use wax however

Rich

It would be interesting to see what they were used for ? That was a very expensive can in it's day . Military perhaps ?

[polaraligned]

They were made for EH Scott radios. These same covers were used on a couple of different Scott radios from 1935 to 1942 when production ended.
Often they are in pretty bad shape, but some pretty decent examples survive. Scott radios are fairly uncommon and desirable radio, some consider the best produced in the 30's, as they were all custom made to order.

This is an example of a Philharmonic that I pulled out of an attic like 10 years ago. Chrome is not perfect, but decent.


Here is one that did not do so well.



Some poor covers.


Platers have had varying success in rechroming these covers. If the oxidation under the chrome is too deep, they are usually not able to rechrome.
I think there was a guy who had these covers reproduced back in the 90's, but I doubt it is cost effective. You are talking about 12 large covers and 22 of the smaller ones on each set.

I just had a plater quote me $250 to $300 each for the small covers, and $300 to $350 for the large covers, and the ones I sent him were in MUCH better condition than the ones in the picture above. He made a big deal about them being aluminum, but there is NO big deal about chroming aluminum. He is charging $80 per hour for his shop guys doing the polishing and he spends his time going to auto shows and selling his service. The prep work is the whole job in plating.

The original covers had no copper strike under the chrome. I can peel the chrome off, but it takes some effort. Often these old radios were put in moist basements or garages after being taken out of service. Once moisture gets to the aluminum, it is all over.

I had a chassis from one of these replated a couple of years ago and the guy totally screwed it up. The chrome is now peeling off the copper with my fingernail. And the chassis is 14 gauge steel so it should have not been any problem. There are really no good platers out there at a reasonable price.

[enginuity]

....the material is critical whether it is aluminum or steel.....

My materials teacher in engineering night school was one of the people who helped developed the particular alloy that is currently used in aluminum beverage cans. I can't remember how long she said she worked on the problem, but I know she talked at length of the alloying materials of magnesium and manganese to be able to draw the can from one blank and how difficult the problem was.

This video is pretty interesting on the subject, including deep drawing:

[plunger]

I did my apprenticeship with a company that made deep drawn aluminium pots.But I was on the plastics section of the company so didnt pay too much attention. This is thirty years ago but for some reason I thought the pots were drawn in two stages. But I thought the second draw was in the exact opposite direction. In other words the pot was turned inside out . I was told this helped to relieve the pot of stresses. I know they also annealed the pot but at what stage I dont know.

[Rich Carlstedt]

.................................................. ........ This is thirty years ago but for some reason I thought the pots were drawn in two stages. But I thought the second draw was in the exact opposite direction. In other words the pot was turned inside out . I was told this helped to relieve the pot of stresses. ...........................................

Yes its a "Cupping Operation" and also refereed to as a "Draw, Redraw" can

Rich

[JoeLee]

The guy in the video mentioned the speed at which the ram forms the can..... I'm surprised at that rate of speed the forming ram doesn't just punch a hole through the disc like a bullet would.

JL.............

[Baz]

Sort of referred to in an earlier post. Before toothpaste and glue tubes were plastic the metal slug was put in the female mould and a male inside mould shaped bar was whacked down so hard the slug melted and flowed up the mould. I remember a school trip where a line of these were banging down at about one a second.

[Mr Fixit]

Hey polaraligned,

There are some paints and other contact materials that sign manufactures are selling that you might look into. There are You tube's on this topic and this company https://alsacorp.com/about-alsa/ a buddy used. I'm not affiliated with them or have I used it but a buddy did and for an interior car trim piece you could not tell the difference even holding it in your hand. The heat from the tubes might be a problem but you might check it out.

TX
Mr fixit for the family
Chris