Do you like experimenting with different craft techniques and upcycling ideas? We sure do, and we love the fact that we’ve received international recognition for being one of the best recycling blogs in the world!!. Those experiments don’t always work out as planned, but I’m happy to report that this polystyrene casting mold, using a repurposed takeaway dish, sure did. And this is the result, a gorgeous Celtic cross full of texture and interest.
Both the hubby and I have Scottish blood flowing through our veins. Mine’s diluted with a bit of Germanic blood, while he’s a 50/50 mix of skirt-wearing ruggedness and little green leprechauns—one of the many reasons I love him so much.
Anyhoos, this bloody marvelous mixture of Celtic blood has crept into our décor, and you’ll find Pictish art and Leprechaun-inspired crafts scattered throughout our home. So this homemade cross fits right in.
This is a super easy repurposing idea, and you can use pretty much any stencil to make a work of art. Plus, you get to use something most people toss in the bin. Talking about throwing stuff out, our International Blogger’s Club (IBC) challenge this month is “Don’t Scrap It”. I think the Celtic cross qualifies. If you want to see more “saved from the scrap heap” ideas, I’ll share what my IBC friends did towards the end of the post.
Okay, before I share the tutorial, be sure to follow us on Facebook, Twitter, Pinterest, or Instagram. And don’t forget to subscribe so you’ll never miss a post!
What you need
You’ll need a large, repurposed polystyrene takeaway dish/plate for this craft. I’m not a big fan of polystyrene, or Styrofoam, as it’s known in some countries. It’s a great insulator, as we proved when we made this chilled beer caddy, but it’s horrible for the environment. Sadly, we get lots of load shedding here in South Africa, and when there’s no power, we order takeaways. And takeaways are usually served in a polystyrene dish. So instead of chucking them out, we save them for cool crafts like these Bali-inspired trees or this Celtic cross. Wash the takeout dish in warm soapy water before using.
You’ll also need the following:
- Left-over spray paint
- Plaster of Paris, casting stone, or quikcrete
- Image – you can download the Celtic cross I used for free here
- Adhesive vinyl or DC Fix
- Cutting machine or sharp craft knife
If you don’t want to bother with cutting machines or a craft knife, you can also use a store-bought stencil for the polystyrene casting mold.
Polystyrene mold casting – how to
Making the mold
Cut the Celtic cross pattern using your cutting machine or sharp craft knife. If you’ve never used a cutting machine, this awesome resource will help a lot. Transfer the vinyl cross to the clean polystyrene takeaway dish.
Make sure to smooth the vinyl down and remove any bubbles. They’ll cause havoc later. If you’re using a stencil, use spray adhesive to stick it down.
Spray paint the vinyl……
……And watch it start eating away at the exposed polystyrene.
Leave to dry completely.
Carefully remove the vinyl.
And that’s it. You’ll be left with a polystyrene casting mold that can be used over and over again.
If you want the mold to be deeper, you can scour it with the back end of a paintbrush.
BTW, did you know you can use cardboard to make molds too.
Casting the mold
We poured casting stone into ours. Plaster of Paris and concrete will work too. The mold is not suitable for resin. Resin heats up as it cures and will melt the polystyrene.
The polystyrene mold is rigid enough to withstand the weight of freshly poured concrete or casting stone…..
…..and flexible enough to easily remove after the concrete or casting stone has set.
The polystyrene mold is reusable. Here’s the first Celtic cross I made after staining it a beautifully rich, golden brown.
It almost looks like leather.
And this is the second one, using the same mold.
I used brown, green, and blue craft paint to highlight the peaks.
The finished piece has been mounted on Yakisugi scrap wood.
Doesn’t it look so cool?
It kinda reminds me of a fossil.
Or perhaps an artifact that’s tarnished over time.
What do you think? Will you be repurposing your takeout dishes to experiment with polystyrene mold casting?
If you like the idea of making this easy polystyrene casting mold, don’t forget to pin it for later.
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More “Don’t Scrap It” ideas
Whether it’s upcycling furniture, repurposing glass jars for storage, or transforming scraps into crafts, reusing throw-away stuff fosters a sense of sustainability and mindful consumption. Something all of us at the International Bloggers Club are passionate about. Click the links below to see what else can be saved from the scrap heap.
- Rachel gave scrap plywood a complete makeover that’s both functional and curvaceously gorgeous.
- Kristin took all kinds of scraps to create an eye-catching display of things that make her happy.
- Sara and her hubby rescue old sewing machines and give them a new lease on life, even when they can’t be fixed.
Oh, and if you’re looking for some of the things we used, 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 make more amazing crafts to share with you ;-)
Awesome stencils if you don’t want to make your own Celtic cross.
And if you prefer to buy rather than DIY, then maybe these beauties will appeal.
And as always, wishing you a wonderful, crafty week filled with lots of love. Thank you for popping in for a visit.
Last update on 2026-04-15 / Source Amazon Affiliates
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