Would an aluminum sheet prevent steel pushing/iron pulling items that are behind it?

[DracoAdamantus he/him]

I know that aluminum itself is allomantically inert, and will not be detected by burning iron or steel. But if there was a bolt sitting on the table, and then a vertical aluminum sheet was slid in the way so that it blocked the straight line between my center of mass and the bolt, would I be able to detect and push on the bolt? I know this wouldn't work if the bolt was encased in an aluminum box, but what about when aluminum just blocks the path of the metal line?

As an extension of this, how exactly do aluminum hats block emotional allomancy? Emotional allomancy isn't sent out in distinct lines like steel and iron, it's more of a wave/cloud. Since the head isn't completely encased in aluminum, one would think that some would still make it through. My first thought is that it doesn't make you completely immune, but it blocks enough from the average soother/rioter (like 95%) that they're basically ineffective. But if there was a sufficiently strong allomancer (either through savantism, spiking, or just stronger powers), they could riot/soothe hard enough that that little 5% that makes it through the unshielded portion is enough to affect someone. 

[Treamayne]

55 minutes ago, DracoAdamantus said:

I know that aluminum itself is allomantically inert, and will not be detected by burning iron or steel. But if there was a bolt sitting on the table, and then a vertical aluminum sheet was slid in the way so that it blocked the straight line between my center of mass and the bolt, would I be able to detect and push on the bolt?

Depends on the size of the bolt and the thickness of the aluminum. Aluminum acts as interference that way, so if there is enough interference, then nothing will happen - but if there's little interference (like aluminum foil) then it's just more difficult and less powerful. WoBs:

Spoiler

Quote

Questioner

In Allomancy, aluminum won't be able to be pushed or pulled, right?

Brandon Sanderson

Right.

Questioner

So if you put a piece of steel like a gun barrel, and then you surround it with aluminum, can you still push the gun barrel?

Brandon Sanderson

The aluminum will add some interference, it's gonna depend on how thick the aluminum is. It's probably unfeasible. That is a viable concept, I don't think it's feasible on a gun barrel.

Words of Radiance Seattle signing (March 8, 2014)

Quote

ccstat

Can a Seeker, standing outside a Coppercloud, that is between them and another Allomancer, can he sense the person standing on the other side of the Coppercloud?

Brandon Sanderson

Yes, but he might get some interference.

Ben McSweeney

Would you sense the cloud itself, like "Hey, there's a cloud between me and what I'm looking at"?

Brandon Sanderson

If you know what you're doing, you might be able to say something is interfering, but you wouldn't be able to determine what. There are multiple things that could cause that, for instance-- Most of them are only-- That they would be able to-- Yeah, there are multiple things that could cause that. Like, for instance--

Ben McSweeney

Big buildings?

Brandon Sanderson

Well, aluminum.

Firefight Atlanta signing (Jan. 24, 2015)

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Questioner

So, if we switch to Scadrial, and I had lined the inside of my hat with aluminum, I'm protecting myself from emotional Allomancy. What if I was able to use emotional Allomancy? Would that block me?

Brandon Sanderson

So, it's going to interfere a little bit. But the issue with that is, a lot of Allomancy is coming from center and going to head. So, you're probably still gonna be okay with the helmet... So, I'm gonna say, you don't want a lot of aluminum around you, but you could probably still make it work.

Oathbringer release party (Nov. 13, 2017)

 

 

55 minutes ago, DracoAdamantus said:

As an extension of this, how exactly do aluminum hats block emotional allomancy? Emotional allomancy isn't sent out in distinct lines like steel and iron, it's more of a wave/cloud.

Emotional allomancy is happening in the Cognitive Realm - allomantic pulses are washing against the Cognitive Identity (what, in M:SH, Kelsier saw as a vague Vin-shaped mist shadow but on Roshar shows as a glowign heal-less flame). Due to consensual reality about the head being the seat of the mind - protecting the head in the physical realm also adds interference in the Cognitive Realm (because the aluminum also has a Cognitive Identity;(SA Spoiler) Mist on Scadrial, beads on Roshar). It's similar to the effect of a Copper Cloud - because the interference radiates in all Realms. 

Spoiler

Quote

<Edited for Length and Relevance>

Phantine

Does that 'inside a body' thing work on most magics?

For instance, if Han stuck Luke into a Mistborn Tauntaun (a distant and unlucky relative of the mistborn llama), would Luke be protected from both the cold and emotional allomancy?

Brandon Sanderson

He'd have to get him inside a living one.

It does work on most magics, though the interactions can be odd unless you know a lot about the workings. Emotional Allomancy, for example, works by lapping against the outsides of someone's cognitive self, influencing you the way music might stir your soul. So being inside a living body wouldn't necessarily stop it--you'd just have more interference. Kind of like how you can still hear music outside if it's loud enough.

Actual mind control in the cosmere requires you to get INSIDE the soul, which you've seen happen frequently enough. There has to be a gap or an opening.

Or, conversely, you just have to be so powerful that you can push through the interference.

/r/books AMA 2015 (July 14, 2015)

Note - it is likely, but not yet confirmed that the Emotion Pulses Vin detected when burning Duralumin+Bronze in WoA to sense Breeze's Soothing are the-same-as/related-to (Elantris and SA Spoilers):

Spoiler

The Rhythms that are sense by Singers and the Emotion Pulses expressed by Seons. 

 

Hope that helps

Edited October 23, 2025 by Treamayne
SPAG

[DracoAdamantus he/him]

1 hour ago, Treamayne said:

Depends on the size of the bolt and the thickness of the aluminum. Aluminum acts as interference that way, so if there is enough interference, then nothing will happen - but if there's little interference (like aluminum foil) then it's just more difficult and less powerful.

My question is more about the way the aluminum is blocking in terms of the position of the objects, rather than the thickness.

Let's say there's a sealed aluminum box with a bolt inside it, and I find that the aluminum interferes enough that I cannot form metal lines to the bolt. If I instead set the bolt on the table, and put just one of the walls of the box between me and it, so that the aluminum was in the way of the direct line between my center of mass and the bolt's center of mass, would I be able to form a metal line to the bolt or not? What if we're positioned in a way that I can actually see the bolt, either through mirrors or angles, but that line from center to center is still blocked?

[Treamayne]

32 minutes ago, DracoAdamantus said:

My question is more about the way the aluminum is blocking in terms of the position of the objects, rather than the thickness.

That's what my answer addressed. For example:

1. Metalborn - 1mm thick Aluminum sheet, 1ft x 1ft on a table - 1" industrial steel bolt on a table
2. Metalborn - 1mm thick Aluminum sheet, 3ft x 3ft on a table - 1" industrial steel bolt on a table
3. Metalborn - 1mm thick Aluminum sheet, 1ft x 1ft on a table - 1/8" steel hex bolt on a table
4. Metalborn - 1cm thick Aluminum sheet, 1ft x 1ft on a table - 1" industrial steel bolt on a table
5. Metalborn - 1cm thick Aluminum sheet, 1ft x 1ft on a table - 1/8" industrial steel bolt on a table

All of those examples are going to have different levels of interference. Ex 5 will probably not form a Steel/Iron line at all; Ex 1 will probably be able to pull/push with some loss of force or latency to get through the interference, Examples 2-4 will be somewhere inside that spectrum from "Slightly more difficult" to "Not possible". But because each of those factors (size of the obstruction, thickness of the obstruction, size of the target) matters - there is no single blanket answer.

Line of sight should not matter at all - because Steel/Ironlines (likely) work on Connection (implied by Era 2 and SA RoW) we often see Allomancers pull and push on objects without line-of-sight. Wax even turned it into tracking targets through walls. What matters is can the MoI "Connect" to the target, then influence the target. 

Most of this will be covered in Era 3 - since Brandon has said that's when Scadrians will really start applying the Scientific Method to the study of the Metallic Arts. 

Spoiler

Quote

Brandon Sanderson (paraphrased)

The "perks" ("secondary effect born with interaction between powers") also has not a 100% sure name, but the main one at the moment is resonances....We will discovered a lot of the in the third trilogy where the Scientific Method would be applied to the magic.

Lucca Comics and Games Festival (Oct. 28, 2016)

Quote

Questioner

How do you go about designing new magic systems? Because that's one of the most amazing things you do.

Brandon Sanderson

I've written several essays about this, so if you go to brandonsanderson.com/writing-advice, you'll find my essays on magic systems. Basically, I'm trying to look for something that I can explore in a way I haven't seen people do before. It doesn't have to be a new power, it just has to be a new take on a power that I can explore, that I can have fun with, that I can find some sort of scientific rigor. I like to have this sort of have one foot in science and one foot in superstition. That's what is fun for me in worldbuilding, this idea that-- I often say a lot of the old scientists, like Isaac Newton, believed in alchemy. Like "If only we could figure out..." and they started applying the scientific method to alchemy. Which is so cool! It's like "If we keep trying, we'll eventually figure out how this works." But it doesn't work.

I like this idea of applying the scientific rigor to something superstitious, and finding that it does work, and then what do you do with that. So that's what I'm really looking for, particularly in my epic fantasies. It's also got to be the gee-whiz, the wow, "This is really exciting. This is really interesting."

Sasquan 2015 (Aug. 19, 2015)

 

Hope that helps

Edited October 23, 2025 by Treamayne
SPAG

[DracoAdamantus he/him]

2 hours ago, Treamayne said:

But because each of those factors (size of the obstruction, thickness of the obstruction, size of the target) matters - there is no single blanket answer.

Right, which is why I clarified with a specific scenario. My question was about how does it differ between something completely shielded by aluminum, and aluminum that is just "in the way" of the direct path. Ultimately, I am trying to figure out what the restrictive properties of aluminum are for investiture, for a concept I have for potential fabrials and malwish technology.

To explain the scenario a different way, I put a bolt in an aluminum box, then burn steel, and get no metal lines to the bolt in the box. This tells me the aluminum has completely shielded this bolt from being steel pushed. The thickness of the metal and size of the bolt don't matter here, because I have a baseline control confirming that this is enough aluminum to block this particular bolt when completely enclosed. I then take the bolt out of the box, and set up a piece of aluminum the same thickness as one of the box's walls between me and the bolt. I burn steel again. One of three things can happen:

1. No metal lines form.
2. The metal line forms, but my ability to push the bolt is weaker.
3. The metal line forms, and I can push on the bolt with my normal strength.

 

Edited October 23, 2025 by DracoAdamantus

[Treamayne]

13 minutes ago, DracoAdamantus said:

To explain the scenario a different way, I put a bolt in an aluminum box, then burn steel, and get no metal lines to the bolt in the box. This tells me the aluminum has completely shielded this bolt from being steel pushed. The thickness of the metal and size of the bolt don't matter here, I thin take the bolt out of the box, and set up a piece of aluminum the same thickness as one of the box's walls between me and the bolt. I burn steel again. One of three things can happen:

1. No metal lines form.
2. The metal line forms, but my ability to push the bolt is weaker.

Yes. One of those two things happens - and which one occurs depends on the size of the bolt, the proximity of the Aluminum and the thickness of the Aluminum. 

[DracoAdamantus he/him]

Okay, I think that ultimately answers my question. Since it may be possible for the bolt to be affected when the direct line between allomancer and bolt is blocked with a thickness of aluminum that will fully block their allomancy when the bolt is surrounded by the same thickness, then that means that the actual investiture directed by allomantic steel and iron is not a straight line like the metal lines themselves, but also in a bubble/cloud (like most of the other external metals) that can "leak" around the aluminum to connect you to sources of metal (just not as efficiently).

Am I understanding that right? That's more or less what I was trying to find an answer to. Another way I thought of to word it would be: "Can area of effect investiture curve/leak around an aluminum shield that isn't 100% sealed?"

Or to make it even more specific: "If you were able to actually see the investiture itself moving to form the metal lines when iron/steel is burned, would it look more like a bunch of individual lines shooting out from you to sources of metal (not the metal lines, I mean how power moves to find the metal to form those metal lines), or would it look like a bubble or a cloud of influence propagating from your center?"

[Treamayne]

1 hour ago, DracoAdamantus said:

then that means that the actual investiture directed by allomantic steel and iron is not a straight line like the metal lines themselves, but also in a bubble/cloud (like most of the other external metals) that can "leak" around the aluminum to connect you to sources of metal (just not as efficiently).

We don't yet have enough information, but I don't think that Allomantic Steel/Iron are a "bubble" so much as that Connection occurs in the Spiritual Realm where space and time don't matter. Aluminum's effect is like a "bubble" (or a Copper Cloud - since that is a similar effet, but in the Cognitive) and if the Spiritual Connection can get through the interference than the Physical Effect of Iron/Steel (which is linear) will still occur (reduced by the interference, as appropriate). Relevent WoBs were in the first post (quoted below).

On 10/23/2025 at 10:11 AM, Treamayne said:

WoBs:

  Hide contents

Quote

Questioner

In Allomancy, aluminum won't be able to be pushed or pulled, right?

Brandon Sanderson

Right.

Questioner

So if you put a piece of steel like a gun barrel, and then you surround it with aluminum, can you still push the gun barrel?

Brandon Sanderson

The aluminum will add some interference, it's gonna depend on how thick the aluminum is. It's probably unfeasible. That is a viable concept, I don't think it's feasible on a gun barrel.

Words of Radiance Seattle signing (March 8, 2014)

Expand  

Quote

ccstat

Can a Seeker, standing outside a Coppercloud, that is between them and another Allomancer, can he sense the person standing on the other side of the Coppercloud?

Brandon Sanderson

Yes, but he might get some interference.

Ben McSweeney

Would you sense the cloud itself, like "Hey, there's a cloud between me and what I'm looking at"?

Brandon Sanderson

If you know what you're doing, you might be able to say something is interfering, but you wouldn't be able to determine what. There are multiple things that could cause that, for instance-- Most of them are only-- That they would be able to-- Yeah, there are multiple things that could cause that. Like, for instance--

Ben McSweeney

Big buildings?

Brandon Sanderson

Well, aluminum.

Firefight Atlanta signing (Jan. 24, 2015)

Quote

Questioner

So, if we switch to Scadrial, and I had lined the inside of my hat with aluminum, I'm protecting myself from emotional Allomancy. What if I was able to use emotional Allomancy? Would that block me?

Brandon Sanderson

So, it's going to interfere a little bit. But the issue with that is, a lot of Allomancy is coming from center and going to head. So, you're probably still gonna be okay with the helmet... So, I'm gonna say, you don't want a lot of aluminum around you, but you could probably still make it work.

Oathbringer release party (Nov. 13, 2017)

Expand  

 

 

Hope that helps.

[DracoAdamantus he/him]

1 hour ago, Treamayne said:

I don't think that Allomantic Steel/Iron are a "bubble" so much as that Connection occurs in the Spiritual Realm where space and time don't matter.

This probably gets into the weird metaphysics of the Spiritual Realm, but how does that work? Space and time may not matter in the Spiritual Realm, but it certainly does matter in the Physical Realm, because you can only sense metal objects within a certain radius of yourself

To clarify, when I was referring to a bubble, I meant the means in which the investiture propagates. If I could see the connections to the metal form in slow motion, in either realm, would that appear as a series of separate individual lines shooting out and connecting me to sources of metal, or would it appear like a shockwave propagating out from my center?

1 hour ago, Treamayne said:

Aluminum's effect is like a "bubble" (or a Copper Cloud - since that is a similar effet, but in the Cognitive)

Ohh okay, so is this to say it's a similar effect to a copper cloud in that where it interferes with an area behind it but not as strongly as the area within it?

To play out a different scenario, let's say I had an aluminum box sealed on all sides, and three identical pieces of metal: One inside the box (surrounded by aluminum), one behind it (aluminum in the path), and one off to the side (no aluminum in the path). We also say the aluminum is not thick enough to completely block my allomantic push on the piece inside the box. When I burn steel, the strength of my push would be weakest against the piece inside the box, strongest on the piece off to the side, and the one behind the box would be somewhere in the middle. Is that about right?

[Treamayne]

7 minutes ago, DracoAdamantus said:

To play out a different scenario, let's say I had an aluminum box sealed on all sides, and three identical pieces of metal: One inside the box (surrounded by aluminum), one behind it (aluminum in the path), and one off to the side (no aluminum in the path). We also say the aluminum is not thick enough to completely block my allomantic push on the piece inside the box. When I burn steel, the strength of my push would be weakest against the piece inside the box, strongest on the piece off to the side, and the one behind the box would be somewhere in the middle. Is that about right?

Sounds consistent with current known data - pending the reveals expected in Era 3.