I’ve been seduced by all the stylish concrete DIYs on Pinterest & Instagram- concrete stools, concrete planters, even concrete jewelry! It seems you can make it all yourself! But how easy is it to actually work with concrete? Even though I’m a DIY blogger, I have to admit that sometimes online DIY projects work out very differently from how they look in the photographs! (E.g. when I made the DIY coaster recommended by a craft blogger- who will remain anonymous- and my hot tea almost spilled onto me because round beads are, well, obviously slippery!) To find out, I did some research, and took a class with the London Craft Club taught by Rhiannon Palmer, who has her own line of gorgeous concrete jewellery.
Note: sorry for not sharing more photos of the class- you can thank Apple for deleting ALL the photos on my iPhone!
Optional for the curious (if that’s not you, skip down 3Qs)
How does it work?
You mix water, cement and an aggregate. Leave it to set, and hello concrete!
So it’s really simple! But, 1 thing to keep in mind is that the proportions are extremely important- too much/ little and it either wouldn’t set or the concrete will be weak.
Aggregate? What’s that?
It’s what it says it is! A mixture! Anything from recycled glass, stones, rock, sand, gravel..
How does it work?
The water makes the cement “grow”, locking everything tightly together.
What you need to know before you DIY
Is it quick to use?
Yes & no. Your part- mixing everything together- is not rocket science. However, concrete needs a long time to set. For example, I had to leave mine in the moulds for about 2 weeks (and 1 still cracked!)- the longer the better because concrete actually hardens for over 5 years from when you mix it all together.
Note: you can make or buy your moulds- making them is time consuming but obviously cheaper! At the Museum of London with the London Craft Club, we shaped our moulds using plastic from old water bottles and food containers. However, they took a while to make, were more or less good for only one use and- if you had a more complex design may have teething problems. For example. my design was basically a brick. How difficult can it be to make a rectangle? When I say complex, I mean how far the shape you want is from the original shape of the plastic. I had to recut everything and tape it all together again, so the mould wasn’t very solid and the concrete actually bent it out of shape, which led to a rather wonky brick 🙁
See how it isn’t quite a geometric rectangle? It’s as though my brick was a python & swallowed something…. The block on the top right is actually stone- I carved it at a class in Angel Islington. Doesn’t it look like the concrete? No wonder concrete is called liquid stone!!
If I worked with concrete again, I’d buy a mould in a shape I know I would reuse
Will my DIYS last?
It depends! Concrete is strong in compression but weak in tension. (What does that mean?!) Basically it can bear a lot of weight, but snaps easily if you stretch or bend it. Which is why you need to add steel to reinforce it!
It’s not fail-safe though. I made mine in a class- Rhiannon works with concrete for a living!- and added the amount of steel she recommended, left it to set for 2x as long as she recommended BUT it STILL broke 🙁 Darn!
Is it safe?
Exposure to the cement dust can lead to eye, respiratory tract or skin irritation. Small amounts shouldn’t be an issue but prolonged, repeated exposure can lead to a sometimes fatal lung disease called silicosis.
Wet concrete is very alkaline and can cause chemical burns on the skin.
I left the class with a lot more appreciation for all the concrete jewelry I’ve seen in the market!
So what do you think? Is concrete a material you’d be happy to DIY with at home? For myself, I’d only use it for small projects, with gloves and a mask, and in an outside space 🙂