Securing Seed Phrase Using Magic Mug Under $15

[Pmalek]

I don't like it for seed backups, sorry. The only slightly safer alternative to traditional porcelain cups is plastic or those unbreakable/break resistant mugs that are out there. But they can't change color like in your examples. Maybe something unbreakable that only glows under UV lights.

But even that doesn't get rid of the problem that someone somewhere has to be trusted with printing the words on the cups.

[m2017]

This looks fun for a qr code showing an address.

Yeah, and when someone wants to pay, then you take out a mug with a qr-code (with your bitcoin address) and hold it out for payment. The advantage of this Magic Mug Under $15 in this case will only be that you can immediately mark the deal by drinking champagne (or whatever) from this mug. 

[LoyceMobile]

But even that doesn't get rid of the problem that someone somewhere has to be trusted with printing the words on the cups.

While we're on the subject of insecure seed storage systems anyway, you can prevent someone from knowing it by using a chalkboard mug.
Don't wash it though!

[sheenshane]

I cannot think of a single advantage this has over just writing down your seed phrase on paper. You should do that instead.

I tend to agree and it shouldn't be your daily use and a mug is a thing that might you're looking for daily in the morning.  It's frangible and isn't right to keep your seed phrase, it might just be for fun but I think if you've valuable stuff, you shouldn't use it daily, or might be decorative stuff in a safe place that you can assure isn't get easily damage.

I'd rather prefer to put your seed phrase in a book and separately right on a page that you've like, for example, your birth date.

[n0nce]

I know it's not 100% secure. It can be broken. So, Don't use it only to secure your Seed. It's interesting, Fun, and can be necessary sometimes.

[...]

Warning: Order at least two Mugs from different shops to print your Seed phrase, and never order online. If you can Order more than two Mugs, It will be better. Use it as a secondary seed phrase backup.

I'm sorry; I commend the effort, but it's a terrible idea. The security issue is not that 'it can be broken'; it's that you're literally giving someone a clear view (maybe even written form) of your seed phrase! No matter how many more backups you have of this seed; you've now literally handed a stranger a copy of your Bitcoin seed words. Dividing it on more mugs just makes it more complicated to restore, seeing as even on this one you made, you haven't numbered the words.

So as Loyce suggested, printing an address QR code or a Lightning BOLT12 QR code would be a 'fun, sometimes useful' gimmick, but please not for seed words.

[BlackHatCoiner]

Perhaps not writing a seed phrase is better than that, lol. 

Further cons:

• Strangers know your seed phrase. (!!!)
• Can't be easily hidden.

Yeah... You don't want that to happen: 

(Taken from Breaking Bad S01E03)

[Agbe]

How can someone save an important keys on a unsecured object? There are two things you must consider:
1. The mug is too open. You can not hide the seed on the mug and also you can not print the seed inside the mug.
2. The mug is breakable which disqualified the mug to be used at all cost. And the changing of the color when used hot water is strange to me. What really causes the change, please tell us more. And also everyone will have access to your secret keys. I must tell you using this your mug approach is much more dangerous or it is at owner risk. Although I discovered that you only made a suggestion not an object that one must use but a suggestion from you that in one who is interested can used to to secure their. I really appreciate your effort for taking time and explain the mug. But I advise you not to use it instead use another metal other users has mentioned.

[LoyceMobile]

With the right paint, you can make the mug by yourself! That's much more secure (until someone sees it) and could make a unique giveaway if you want to donate some Bitcoin to a friend.

[Pmalek]

And the changing of the color when used hot water is strange to me. What really causes the change, please tell us more.

The magic behind the color-change is explained here, for example. There are two main elements that affect the change: heat-sensitive paint and the thermochromic ability of the material the mug is made of. When the temperature in the mug changes, thermochromism causes the change in color. Read the whole blog post if you want more detailed information. There are many other sources available online just like the one I linked to.