Have you seen those beautiful giant keys? Please tell me you have. They’ve been popping up on my Pinterest feed this last week, and I really, really wanted to try and make one. A lot!! And I think I managed to pull it off with this faux metal gigantic rustic key.
When I started planning the key, I had absolutely no idea if it would work.
But as they say in the classics you never know until you try 😉
And you’ll be glad to know you don’t need any fancy paints to pull that gorgeous rust effect off either. Just a few spices and water.
Okay, before we get to the tutorial, be sure to follow us on Facebook, Twitter, Pinterest, and Instagram. And don’t forget to subscribe to our monthly newsletter so you’ll never miss a post!
How to Make a Giant Rusty Key
Our faux metal key is about 50 cm long, or 20″ for my American friends and it was one of those projects that really frustrated me at times, but I am so happy with how it turned out. If you’d like to make one all you need is some cardboard, paint, coarse sea salt, nutmeg, and expanding foam. That stuff you use to fill gaps with. Any brand will do.
I found this basic key on the Graphic Fairy and used it to create a cardboard template for our key.
I considered going for something a little more intricate, but I think this technique is more suited to something simpler. Use a sharp craft knife to cut the key out of cardboard and place it on a sheet of plastic.
Grab some of that expanding foam and spray it all over the cardboard key, and wait for it to dry completely.
Ours took about a day. When it’s dry, use a craft knife to carve out the key shape. Start off by just cutting away large chunks of the foam and then whittle away the rest, little bits at a time. I promise it’s easier than it sounds and I found it very therapeutic. And if there’s any expanding foam left you can always make this adorable fairy toadstool
Don’t worry too much if there are gaps or air bubbles in the foam, it will add to the faux metal effect later.
Adding the Rust Factor
We used some Gesso to smooth out any rough edges, but if your carving skills are better than mine, it’s probably not necessary. Gesso is the stuff artists normally use to seal their canvas before painting and you’ll find it at most craft stores or you can make your own.
Paint the key in a copper brown color. You can use acrylic paints or spray paint, whatever you have in your craft cupboard. Once the paint is dry, spritz the key with water and then randomly sprinkle some coarse sea salt all over the key.
The sea salt melts and creates a barrier for the next layer of paint. Wait a few minutes for most of the water to evaporate, and then spray the key a deeper, darker brown.
When the paint is dry, just brush the salt off, and you’re left with this gorgeous pitted effect.
Now for the nutmeg. Bet you were wondering what on earth that had to do with the whole equation 😉
Smile; it's the key that fits the lock of everybody's heart
Add little dabs of glue or mod podge and sprinkle the nutmeg all over the key to create some yummy, delicious, rusty awesomeness.
Be generous with the nutmeg, especially in the air bubbles.
That’s where rust would naturally form if the giant faux metal key had been lying in the rain and snow.
Seal the gigantic rusty key with a clear ,matt varnish.
What do you think of the giant rustic faux metal key? Would you add something like this to your decor?
If you like the idea of making a faux metal gigantic rustic key, don’t forget to pin it for later.
I’d really love to hear from you; comments always make my day. Oh before I forget, if you’d like to make something similar or prefer to buy rather than DIY, we’ve got you covered. Disclosure: Clicking on the links below means we may receive a commission from Amazon. But don’t worry, it won’t come out of your pocket, and it helps us come up with more crafty ideas to share with you
And as always, wishing you a beautiful, crafty week filled with lots of love. Thank you for popping in for a visit.
Last update on 2026-08-16 / Source Amazon Affiliates
74 comments
Thanks so much for posting this! I’m using your step by step tutorial to create an old key for a musical production. This has been extremely helpful.
You are so welcome, Ally. It always makes my heart do a happy dance when I hear that one of our tutorials helped someone out. Wishing you all of the best for your musical production.
Wow, that’s incredible Michelle, and it looks just like the real thing! Nutmeg and expanding foam, who would’ve thought?
Thanks Marie. Spices are my go-to for faking rust. So easy and inexpensive 😉
How long did this take you?
I spent a day making the key. The foam takes about 4 hours to cure properly so I had to wait for that, before carving the key shape which took about an hour. The painting was really quick.
is the key 3d or is it flat on the backside? or do you make 2 sides and glue them together?
Hi there Dale, the key is flat on the backside, but your idea of making two and gluing them together will most definitely work too
Can you use brushed on acrylics over the salt layer too, or does that need to be spray?
I think the acrylic over the spices would either wipe the spices off or the they might dissolve. I’m afraid I’ve never tried it though. Sorry Gabrielle. If you do give it a go let me know how it turns out if you get a chance
Did you get the Key template printed off at some sort of print shop to get the size?
Hey there Ariel, I used a free online tool called blockposters.com. It allows you to create a big sized poster on different A4 pages. Once it’s printed on your home printer you can just sick the pages together. Hope that helps
I used your awesome key idea to make a sign for my nieces “Secret Garden” wedding. I’d love to send you pic.
That would be so lovely Donna. I would love to see it.
Awesome accent piece. Love it!
Thank you so much Joyce, I appreciate that 😀
I just discovered your blog, from Sadie Seasongood’s Talk of the Town. I am in LOVE with your suitcase parts embellished chest of drawers, and thought I would look around your blog to see what other clever things you have here…this foam key is amazing! I’m subscribing and looking forward to future posts!
Thank you much Linda. I really appreciate it. I must admit I’m terrible at sending out newsletters, I just can’t seem to find the time to put them together but i so appreciate you subscribing and hopefully on day I’ll get my act together
Absolutely amazing
Q: What fixture is used on the foam key to get it to HANG-UP on a wall?
Thanks so much Pippie. We just screwed in two small hooks at the top of the key and hung it up with a rope. Let me know if that helps, I can always take another photo 😉
Finally had a moment to check out how you made this key! I love anything and everything rusty so this caught my eye when you first posted it. I LOVE IT…it turned out sooooo AMAZING!!! Thank you for sharing…I will definitely be making one of my own!! 🙂
I’m so glad to hear that Michelle 😀
Wow Michelle your key is amazing, what a brilliant take on the wooden ones you saw originally. I think you have done a fabulous job here, it looks so realistic. You must be delighted with the result. Thanks for sharing your step but step instructions too. I will add this to my ‘Must Try’ projets list 🙂
I will head back to your blog now to read and see more of your ideas.
Thank you so much, I really appreciate that 😀
Love it So realistic, aside from the size. Thanks for how to. Maybe some day I’ll make one.
Thank you so much Cath, I hope you get to make one someday
So cool! I was wondering it it would be possible to make a large key because I wanted one as a photo prop. Thank you!
Thanks so much Natasha. This one is quite big, about 50 cm long, if I remember correctly. How big does your key need to be?
Michelle! This is amazing! I had no idea you could use spray on foam to carve things! Now my DIY senses are tingling 🙂 Lovely tutorial – and so smart with the nutmeg! Lots of love, D x
Hello Dani, how you doing? I’m so glad you like it, that spray foam is amazing. I need to scratch around in hubby’s garage more often 😉
How weatherproof is the key after you have applied the nutmeg? Im thinking some glues and podge may not be entirely waterproof?
Great question Chasey. We had a huge thunderstorm last week and the key blew off the wall (expanding foam is really light) and ended up in the garden. The paint, the nutmeg, the mod podge all held up and our key is back on the wall. You can apply a clear matt outdoor varnish over the key if you’re worried.
Wow! You’ve done a fantastic job with the key Michelle. I actually didn’t know they were popular, though I must admit I love old(fashioned) / skeleton keys and use them quite often in my jewelry. Imitations, that is – not real keys 🙂
Thank you so much Maya. I’ve seen all the beautiful things you’ve made and I’m so envious of your crocheting skills. Your work is lovely