The part in the middle which retains the heating element is what I know as aluminum. A pale color and a really soft feel.

The plate at the bottom is something new to me. It feels more solid, it has a stainless color and a shiny finish. The only thing I can say about its properties is that in non-magnetic.

On the product website they say that it is 6061 grade aluminum but the website is not so thrustworthy to me so that's why I'm posting here.

Is it what this grade of aluminum looks like?

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  • $\begingroup$ it looks like some kind of metal alright, you'll need to find other characteristics and test those, or only check specifically those you require from the metal plate. $\endgroup$ Commented Apr 17 at 13:12
  • $\begingroup$ I don't see why they would mislead you about this. If you want to be convinced it's an aluminum alloy, check its density, that's pretty easy at least $\endgroup$
    – Pete W
    Commented Apr 17 at 13:21
  • $\begingroup$ What would you expect from 6061 grade aluminum? $\endgroup$
    – Solar Mike
    Commented Apr 17 at 14:33
  • $\begingroup$ You can’t really determine 6061 from 2024 or other common grade of aluminum by its looks. Unless it’s a highly stressed part I’m not sure why it would matter. $\endgroup$
    – Eric S
    Commented Apr 17 at 15:59
  • $\begingroup$ From the pictures, I'd say the color is not right for stainless but there are as many types of stainless as there are types of aluminum alloys. In the meantime, if it is stainless, why would they say it is aluminum which costs less and has much better thermal conductivity. $\endgroup$ Commented Apr 18 at 22:33

2 Answers 2


The bottom part looks just like sheet aluminum, but its appearance does not reveal its alloy composition. 6061 is a high-strength grade of aluminum, commonly used in airplane construction. It costs more and is far harder to work with than ordinary aluminum (sometimes called 1000). Its use as a heat spreader plate doesn't make any sense unless it just happened to be what the manufacturer had lying around the shop at the time.

  • 1
    $\begingroup$ Pretty certain 6061 is the ubiquitous "compromise alloy", used for solid parts due to its medium strength and decent (but not max speed) machineability ... The finish does indeed look like sheet $\endgroup$
    – Pete W
    Commented Apr 17 at 20:44
  • $\begingroup$ @PeteW yeah but if it's in its T6 temper it's a bitch to drill & saw especially by hand. I hate working with that stuff. $\endgroup$ Commented Apr 18 at 0:13
  • 1
    $\begingroup$ Where I live, 6061 is the default. I would never be surprised to see a part made out of it. $\endgroup$
    – Drew
    Commented Apr 18 at 13:46

The surface finish might tell you about the fabrication method, but not the alloy (it can also tell you about whether it's been anodized, but that's largely independent of alloy as well).

It looks like the smaller piece might be an extrusion, while the larger piece looks like a rolled sheet.

6061 is used quite a lot for both, so it's entirely possible they're both 6061.

But you can also get other alloys in either extruded or rolled sheets, so it's also entirely possible that neither of them is 6061. At least from what I've seen, 6063 seems to be more common than 6061 for extrusions.

Strength and hardness depend heavily on heat treatment, so it's entirely possible for one to be substantially harder than the other, even if they're exactly the same alloy.


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