What?!
I had this idea to test out an interesting way to store a backup seed phrase. It ended up being quite experimental. I used what I had at home and impulsively went through it when I had a spare chunk of time. Any handyman types reading through this here will probably have a lot of advice for me, but having made a few mistakes, I think the next one will turn out a lot better.
It was inspired by a combination of two encounters. One of them was from a guy I met on a gig a few years ago. He was telling me all about how he fixes up old cars (like really old, sometimes 100 years old!) and sells them again. He was talking about a type of building metal that you can mold and shape with your hands. He often uses it to fill holes or to make parts that aren't produced anymore.
The second one was when I was playing playdough with my kids, molding different animals. I was thinking about using this "metal dough" stuff and submerging a stack of steel washers into a shape that can be hidden in plain sight.
And what kind of a shape could a stack of steel washers fit in?
A MUSHROOM!
An "experimental" mushroom. I'll put the stack in the middle of the stem and place the nut into the head and it will sit nicely as an unassuming prop in the front yard with some garden gnomes and stones.
These were the materials I used:
- smaller size steel washers
- nut and bolt
- character punching kit
- hammer
- anvil
- metal epoxy 57g x2
- paint
- sandpaper
Besides the metal epoxy I just used whatever I had lying around in the garage. I think I spent about $20 USD on the epoxy.
Working With The Epoxy Metal
I watched a couple of videos to see what I was in for. You get up to 5 minutes to mix, then 1-3 minutes to get it right before it sets. I made sure I had the stack of washes on the bolt ready to be submerged. Mixing felt a lot harder and stickier than playdough (should have worn gloves). I think I could have spent a little longer mixing, but the texture looked pretty consistent.
Putting the epoxy around the stack seemed to be a little wobbly but it didn't take long until it was fully submerged with a small part of the bolt sticking out of the top.
I used another piece of epoxy for the mushroom head. I mixed it like the last one, then tried to push it into each face of the nut so that it would be fixed. After, I flattened it around the edges and pushed it into the wooden table (which later got stuck). This turned out ok but since the nut was quite small in comparison to the head, there may have been some slight gaps on the face of the nut. This caused it to slip on the bolts thread later.
I left it for 12 hours or so to set.
I put the head onto the stem but there was a gap in between. Since I'd already used all the metal epoxy I just used some wood putty to fill the gap. After it dried I sanded back some of the bits sticking out.
Next I tried painting the mushroom with an orange color I had. The paint wasn't really designed for metalic surfaces so there were lots of streaks. I tried a few coats, but it wasn't really working. So I switched to covering the mushroom in glue and then sprinkled sand all around.
At this point it's starting to look pretty weird, but also ideally discrete. I left it in the front yard for about 2 weeks next to a solar mushroom light and some succulents.
Then I took it out back to recover (smash!).
The metal epoxy was surprisingly strong. I hit it quite hard with a hammer multiple times before breaking it. I thought that it would just crumble like wood putty or shatter like glass but that was not the case.
The steel washers were of course recovered without any damage.
How To Make A Stack Of Steel Washers Submerged In A Garden Mushroom
Now that I have been through this experiment, here's how I would improve on it.
Materials:
- smaller size steel washers
- nut and bolt
- character punching kit
- hammer
- anvil
- metal epoxy ~100 grams for a 12 word seed.
- paint specifically designed for metal surfaces
- rubber gloves
- sheet of plastic or non-stick material
- sandpaper
NOTE: Make sure you have stamped your seed into the steel washers correctly before starting.
- Mix a small bit of the epoxy (1/10th) to wedge between the washer and the bolt. You can do this for a few washers at a time until the whole stack is fixed. Wait an hour or so for it to set.
- Place a nut on the bolt thread to position where the mushroom head will sit. Mix around 2/5th of the epoxy to wrap around the washers making a mushroom stem shape. Make the bottom flat and the top level with the base of the nut. When the desired shape is complete, take the nut off before it sets. Let it set on a non-stick material like a sheet of plastic.
- Mix 1/10th of the epoxy and place around the nut only leaving the bottom exposed. Make sure there are no gaps around the edges of the nut. Let it set.
- Mix 3/10th epoxy to expand the nut into a mushroom head. Place the nut into the bottom middle and shape as desired. Like the stem, also let it set on a non-stick material.
- Use the remaining epoxy to seal the stem to the head. Place the head on the stem and use the remaining epoxy to fill the gap between the stem and head. Let it set.
- Using some sand paper, sand away any excess bits or smooth out the appearance. 7 Paint mushroom as desired.
Why do this?
I quite like the humble stack of steel washers. They're available all around the world, they're cheap, and they prevent even the most devastating situations like a house fire from destroying your sats. Burying them underground is a good option if you own the property that you live in, or know a good place to bury it that no one will ever build on. Retrieving these from underground is quite a hassle. The deeper you bury it, the harder it is to retrieve. If you ever move house or area you will need to dig it up.
So another option is to hide it somewhere. Leaving it as it is (a stack of steel washers) could be dangerous as anyone interested in bitcoin will instantly know what it is. So for this option it might be a good idea for someone to have it hidden in plain sight. Molding the steel washer stack into a shape like a mushroom to be left in the garden seems quite discreet to me. If you have it lying around with other garden gnomes or stuff that you put in your garden, it just sits there unassuming. It doesn't necessarily need to be a mushroom either. It could be a stone, a gnome, a cat or a rat. I just chose the mushroom as a basic starter that I knew wouldn't take much skill to mold.
I think it's interesting to explore different ways to store your seeds or passphrases. Working with metal that you can mold opens up other options.
Enjoy!