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ride5150's Avatar

Hi everyone, allow me introduce myself. I’m a working structural engineer that has been working on an idea for a few months. It has taken me from buying a 3d printer to casting aluminum in my backyard. I have finally gotten my idea to “work” but now am in desperate need of manufacturing advice.

Here is my question:

How are double-walled stainless steel items produced? Examples of this would be a double-walled steel thermos (not vacuum sealed) and double-walled stainless steel bowls.

Deep draw? Metal spinning?

I thank everyone in advance, need to figure this out to move onto the next step.

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williamj's Avatargold

Hi Mike C and Welcome to EdisonNation and the EdisonNation Forums !

I’m not a manufacturing type person but I did try a quick Google on “how to do double walled stainless” and got virtually nothing.

However… common sense tells me that there are two shells made (probably stamped) and then joined (welded, braised, soldered) in a heated environment. Once sealed together in that heated environment a vacuum would form naturally. Or not.

Just a thought, you might want to visit this thread and ask you questions there.


Best of luck to you and your ideas

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kdc's Avatar

Maybe this might help you? It explains the process. It doesn’t make much sense to me, but for someone like you, you might be able to understand it. Good luck and welcome to EN!


Opps…maybe not, it says ‘Vaccuum seal’.

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psinventor's Avatargold

I believe each side is heat stamped , then assembled , then the edges are rolled crimping both parts together.

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dxflyer's Avatar

Welcome to EN Mike! You’re gonna like it here.

I’ve worked with SS before, it’s not the easiest of materials to work with. If it’s thermal protection your looking for, you might want to try using a heat resistant foam instead. There are many on the market, one that comes to mind is ‘Great Stuff Firebrick’. We use this stuff when sealing off flues in commercial buildings or in firewalls.

Happy Inventing

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riccihaworth's Avatar

Hello and Welcome to EN Mike!

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ride5150's Avatar

Everyone, thank you for the warm welcoming and all your advice!

willamjgrinch that is the exact difficulty i’m having. I can’t seem to find any documentation on how they are made. I think what youre saying makes sense but one think is odd to me. I bought a double wall mug just to see if i could find any clues on how its made and it is completely seamless.

Is there a cost effective joining method for stainless steel that is completely seamless? Doesn’t “need” to be seamless fo rmy application. The rolled+crimped method Jim suggested would work fine. Not sure if this would be watertight though? Can they crimp hard enough to form a water tight seal?

Jonathan foam would not work for me in the application, i would need to contain it in between two walls of stainless steel so might as well just use the double wall itself. Thank you for the advice though!

Kathleen I’ve began deciphering the patent, hopefully ill make sense of it:)

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dxflyer's Avatar

The SS cup might have been welded then sanded smooth. There’s a process known as (ERW) Electric Resistance Welding, where the metal is fused using an high amperage coil.

You could try fitting the two sides together like a collapsible cup where they’re a tight fit together, this might provide a semi watertight seal with no welding involved.

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