Why not make your Halloween designs last forever?! You guessed it these are all concrete!…
Now that you have made your mold as shown here from Part 1, you are now ready to Cast your own Concrete Critter. Don’t worry, this is the easy part…
You now have made a mold with some seams that open for removal. Congrats on the hard work! If you are a bit scared of working with concrete you may want to check out this post on ‘Tips & Tricks’.
The Concrete Mix:
Again, as in my other concrete projects (here) I have used my favourite premix; Quikrete Sand Topping Mix. Cheap and strong stuff. It is a pretty basic concrete mix that does NOT have large aggregate (big rocks) in it, only sand and portland cement.
Update: If you want to work faster; I have found a mix that is unmoldable in 1 hour! RapidSet CementAll. It has worked quite well with my other ‘Bunny’ casting project.
Add some Quikcrete mix to your bucket and slowly add water a little at a time making sure to stir to the bottom. (Do wear a good dust mask rated for concrete work.)
To give it extra strength I have added some fibres. You can get them at any building supply place as well. If you are resourceful you could probably make some by cutting up yarn or string into pieces. They disperse themselves and help keep the concrete from cracking. The parts that tend to break are the thin ones like beaks or feet.
Your mold will need to sit level. I have filled a container with sand to cradle the head and keep it stable. Prop yours up with whatever you have, rags will also work well. Secure the mold together with elastics/string. I have also discovered that this material will allow pins to push through to line up the edges.
The Pour:
You have 2 options for pouring. If you use only the Quikrete mix you will probably have a more rustic pour with some bubbles on the surface. If you take extra care to vibrate it and poke with a skewer, there may be quite minimal bubbles.
Your other option is to coat the inside surface with a slurry mix of just portland cement. Portland cement is the active part of the cement mixes that binds the sand/stone/whatever into the solid form. Mix a small amount to a somewhat runny mix, like melted ice cream, and pour into the mold. Turn the mold round and round til it just coats the inside surface. Jiggle and tap, and it will flow. This will give it a pretty solid coating on the outside that is less likely to have any bubbles.
Once it is coated (or if you chose not as I have since I like the rustic look) you can fill the mold with your Quikrete mix. It is really crucial that you get it in every nook and cranny. I use skewer sticks to poke everywhere, and jiggle and vibrate. You don’t want a missing beak or eye! Tap the sides and turn the mold to get the mix to fill the tail.
If the weight of the concrete pushes the mold add strong elastics to keep it closed. Level off the opening as this will be the flat base that it sits on. It is now ready to set. Don’t be over anxious to take it out early or you will break off the tail. Ask me how I know?! A good 24 hours… (depending on your conditions of temperature etc)
The finishing:
I have a really really great “Tip” that I discovered. After pouring my bowls I would sand them as well. I was frustrated with how flimsy the sandpaper I bought was. (ok, it was cheap stuff) and I saw a disk of extra concrete that I had just poured on a stone, like a coaster. I asked myself, what is sandpaper? It’s sand, just like what is in concrete. So I used this disc like a sanding block and it worked nicely to smooth out edges and seams. It is solid ‘sandpaper’.
Here are my home-made sanding discs. Pretty ingenious eh?!
Since the mold has openings, the seam lines may show as pointed out here. Take the disc or your regular sandpaper (or even a file) and smooth them off. It is concrete, not plastic, so it is quite acceptable to look rustic in my opinion.
In this world of digital reality I like some REAL TACTILE texture! Old concrete sculptures have a great ‘patina’ of texture so I really don’t mind having some here.
Here is the little fellow. Rough, yes, but it provides a nice accent to the stones and foliage. If it didn’t come out quite as you expected, you can cast again. That bag of mix will make a LOT of little critters! Make gifts or even indoor accents. I can imagine many uses and shapes. If you are really creative, make your own sculpture with Fimo/Sculpey and then use it to make a mold. Now you are completely original; casting your own sculpture
Tada! It is a ‘Small project’ yes, but still quite unique and still gratifying. Well done!
‘Want more concrete projects from this concrete-crazy Gal?
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Great idea. I will try this. Been working in concrete over 10 years.
me gusto mucho toda la explicacion , con gracia en la redaccion , muy agradable, muchas gracias
Thank you for sharing this clever project. I can’t wait to make my own! I will also make some sanding stones. That was very ingenious as you said! I am going to use them on other projects as well. Great project, thank you!
Glad to help. I can’t wait til it gets warm again to be able to cast, as ideas keep popping into my head….
Thank You Barb
Thank you,love the way you explain the whole process.I look forward to trying this.
You are welcome! I have a few new ideas awaiting the weather to change. I love making in concrete. Check back often…
I have made several of these and I am having great success. (And fun) I just reread your blog and noticed you didn’t spray the inside of your mold with any kind of release like cooking spray. I thought it was necessary. I was going to do the Portland cement slurry to get the smoother finish but with the cooking spray it wouldn’t stick to the side. So am wondering if I should forget the spray.
I love playing with cement. the possibilities are endless. I can’t wait to see what you will be doing this summer.
How coincidental as I’m sitting here trying to figure out how I can do some casting today (as it’s snowing outside). I’m so happy that you’ve made some with great success! No, I didn’t use the release. A lot of the time if the mold is smooth plastic I don’t need it either. When I casted my ‘stamps’ I didn’t use a release either. That silicone/starch mix doesn’t seem to stick too much so the concrete doesn’t stick easily. I am able to scrub my molds and stamps quite well to clean them too.
Yes, do check back or subscribe as I think concrete my be my favourite project media… Let me know how it goes, ‘would love to see the results.
I was working on some new casting and I have tried some new mold release. I don’t like the Pam spray since it’s messy and made up chemicals probably. I made a thick paste of beeswax and petroleum jelly (vaseline) to keep my boots waterproof. It is thick and greasy but it can be applied thin with a stiff brush. The key is to be sparse, kinda a bit greasy, like our noses(LOL) just enough to prevent sticking… Worked well on my small castings. I thought I’d share
Have used mineral oil mixed with petroleum jelly to a thin syrup consistency for mold releases…works every time.
Thanks for the info! ‘Will try it, but I generally find not much is needed! Concrete on!
Awesome! I bet you use only a little? Maybe apply with a brush? I have also heard that a spray with WD40 works! Lots of fun!
Hi Barb. I love your ideas! can you tell me how you store the silicone moulds and how long they last for?
I have kept them in my shed and in the house. They have not changed in any way that I can tell and it’s been over one year! They seem just the same, not any more stiff or brittle. I guess its like what they advertise for silicone; stays flexible for long time… I have used some dozens of time and don’t see any deterioration. Good luck
Barb, I love your postings on pinterest. You are very generous to share your knowledge. I am a beginner to sand casting leaves in cement and want to explore further possibilities. I was wondering how to affix a cement bird made from the mold to the rim of a large cement leaf ?
Thanks! I bet the bird is not that large and there is a bit of ‘play’ in how it sits. So I would think you need a fairly thick type of adhesive. I like to use 2 part epoxies (especially the 5 minute kind) or the PL construction cement. I once glued some hooks on a brick wall with epoxy, and they are still there 26 years later… Just make sure the pieces are bone dry
Happy concreting…
Wow! Thanks so much for this! Do you think I could do the entire thing with Portland cement for a smooth look? The item that I’m wanting to make a mold of is smooth and I think would look best that way. Thanks!
Since that post I have also been using the RapidsSet Cementall and it is a very smooth setting concrete, smoother than the Quikrete I used then. It is also crazy strong. Check out the bunnies. Hope that helps. Portland cement would need some type of ‘aggregate’ like sand etc…
Do you know about how many time you could reuse the mold? And do you think it would work in a larger form? (as in a long stepping stone about 30″x9″). Thanks!
I have used some of my molds over a dozen times. I see no deterioration. I made a large one for the faces and cast 7 so far. It is quite large so I use a bed of wet sand to stabilize if the mold is thin. Hope that helps, ‘would love to see end result!
Would be so much more interesting with a few photos.
I am not sure what the problem is? Maybe a bad link from Pinterest? This post has many pictures.
Wow, great source! Thank you for sharing it!
I keep going back to that mold making as it has a lot of potential and lasts well too! Check out the other projects under the Home menu> concrete>
Do you sell your decorative molds? I cast cement.
Thank you, Sandra
It would feel wrong to make a mold from existing objects that were made by someone else. The best thing would be to have originals sculpted and then a mold made. (as my bunnies)
Hi Barb
I just came across your site. I have been searching for a simple, no fuss way of making my own garden and indoor concrete art. Thank you so much for sharing your knowledge. Can’t wait to give it a try 😀
I remember fondly of my first concrete project, the stepping stones… the rest is history. You may want to check this out too!
Are these molds reusable?
Oh, yes! I have had them in the shed and they do not seem to change at all even with the winter. I’ve used each of mine multiple times.
Hello I am glad to come upon your blog, I bought at auction some old cement acorn shaped statuaries, which I discovered had damage after the purchase. I would like to make a mold following your instructions. They are aged and darkened wth time, any ideas for making them darker when mixing my concrete? They seem to have more small stones in them also.
There is concrete colour available at local building supply stores. If you use a rapidset it will not look so grainy as traditional concrete. The cream wears away over time to expose the sand and aggregate. You could use a sand topping mix depending on size. Latex/acrylic paint can also colour concrete but the rapidset mixes are moe sensitive to additives. You could ‘stain’ it afterward as well like I did
Hi barb! The molds are reusables?
Oh yes! They last very well eve have them in the shed over our canadian winters! Happy making!
Retired , always looking for extra projects to work on. Thanks for posting, this will keep me busy
Lucky you! Happy and fun times making!!!
you have the best tutorials…. unfortunately we are heading to winter so not the best for drying things…. going to try this in the spring tho…. is there an alternative to using fibreglass straw ? i recently covered a hairdressing head into a planter inspired by you , using grout mix and 50/ 50 mix of water and pva….. worked fantastic , set like a rock and quite weighty … anyway , i digress, thank you again 🙂
Yes, I can’t wait until I can make a mess outside! It’s still freezing here. I have done some small scale projects in the house though. Like my bunnies Even these were made in the house. Thanks for the kind words!
Do I need to put Vaseline *In* the Mold before I put My Concrete in
This mold allows easier removal of concrete if you use a bit of a release agent. Vaseline will work, just be sparing with use. Some molds are tricker to get the shape out so the release agent will help.
Wonderful tutorials!!
Thank you soo much!
Can you use acrylic fortifier made by Quikrete instaed if fiber in the molds for the added strength?
I think you could! The issues are usually the thin parts like the tail. Rapidset Cementall is VERY strong, but much smoother finish.
Hi Barb,
To get the bubbles out of the mold you said to use a slurry of Portland cement and swish it around. If you use Rapidset would you still use the cement or just a watered down slurry of Rapidset?
Rapidset Cementall is a very fine mix, yes a slurry of it in a thinner form will also make for smooth finish and less bubbles. Tap to get bubbles to rise out.