Hemalurgy & Feruchemy question

[Shardigrade]

So, we know that hemalurgic spikes have to be stored in blood, or else they lose charge. We also know that a spike can never completely lose its charge, it's like an exponential thing where the spike deteriorates very quickly when it is first created and then the deterioration rate decreases and flatlines. For allomantic spikes, this makes sense- depending on the potency of your allomantic ability, you can be stronger or weaker (ie elend vs vin in emotional allomancy power). 

But my question is, how does this work feruchemically? If I were to create a spike that lets me store my weight, leave it out until only .01% of the original potency remains and then spike myself with it, would it limit the amount of weight I store in a metalmind? Or would it affect the rate at which I can store and tap weight? To this point I'd like to bring up the scene in which Wax depletes his ironmind in his manor to break through the floor and save himself, Wayne, and Marasi from his butler's bomb. It seems to me that in this scene, Wax dumps all of his stored weight in but a moment; it's not like he can only take out 5 pounds a second, or something like that. Is this because he is simply a feruchemist, and anyone with even the smallest bit of skimmer ability could do what he did, or is it because he is a strong feruchemist, and there are other skimmers who could not do what he did as quickly (or even others who could have done it quicker)?

TL;DR- is feruchemy either on or off , or can you have weaker or stronger feruchemical ability based on various factors just like allomancy?

If anyone has anything to chime in with, it'd be much appreciated  thanks!

 

[Nohadon he/him]

There are a couple answers to this question.

1. In the mistborn RPG handbook (which I have no idea if it is cannon, but might help answer this question) there is a feruchemical skill rating, this can mean the ability to be able to accurately manipulate you levels of storing, but I think this is natural-born skill, not hemalurgic decay.

2. With hemalurgic decay, I'm assuming it has something to do with storing and tapping efficiency, EG: when a normal iron ferring stores 100 charges of iron feruchemy into an ironmind, 100 charges are in the ironmind, when he taps, he can tap up to 100 charges. But when someone has been spiked and the spike has decayed for a significant amount of time (not an actual unit, just an example) the Iron ferring stores 100 charges but only 50 charges actually go into the metalmind, so the spike affects storing efficiency, same if someone has multiple spikes of the same metal, but this increases storing efficiency. store 100 charges and the metalmind has 150 charges, for example.

Here is a relevant WoB

https://wob.coppermind.net/events/10-calamity-chicago-signing/#e6560

Kurkistan

How exactly does Hemalurgic decay work for Feruchemy? Is it like a leaky tube or something, or…?

Brandon Sanderson

Yeah… yeah.

Kurkistan

So they try to store 10 units of health and only 9 gets through, or…?

Brandon Sanderson

Hemalurgic decay meaning someone who has been spiked is less powerful? That Hemalurgic decay, or the Hemalurgic decay when a Hemalurgic spike is left outside of blood?

Kurkistan

Less powerful. So like the Inquisitors are less powerful Feruchemists so they had to spend longer storing: so why did they have to spend longer storing?

Brandon Sanderson

Yeah they lose a little bit, it’s a leaky… You’re there, exactly. It just doesn’t quite… it’s not as efficient: it’s an efficiency thing.

source Edited June 11, 2018 by Nohadon
Added in WoB

[+hwiles]

A more veteran sharder can find the WoB, but yes, efficiency of both storing and tapping is reduced for people with feruchemical abilities gained through hemalurgy. Essentially, when they store an attribute, some of what they are storing just gets lost to wherever waste Investiture goes (presumably the spiritual realm) and when they tap their metalmind later some of the reclaimed Investiture also gets lost.

Not sure if it has been formally canonized that all natural born ferrings are 100% efficient but, at least as of a few years ago, that was the major consensus.

[Nohadon he/him]

I added the WoB

[Oversleep]

11 hours ago, Nohadon said:

same if someone has multiple spikes of the same metal, but this increases storing efficiency. store 100 charges and the metalmind has 150 charges, for example

Efficiency can't go beyond 100%. You can only get so much in the metalmind as you stored.