Hollow Tiny Geode Concrete Orb
I kindly blame ‘Mother Nature’ for most of my inspiration! I take pride when I can somewhat mimic what occurs naturally in nature. This Hollow Tiny Concrete Geode Orb is my handmade version of those special sparkling rock orbs…
The Simple Materials:
Call me ‘kinda’ crazy but I get excited when I see broken safety glass; the kind that comes from windshields or special table tops. I have yet to come upon the opportunity of cleaning up after a large window demise. The glass breaks into small little squares for safety. These are more safe (but still glass so handle with care) than the usual glass shards from regular glass.
When I would make my huge concrete geodes it was troublesome to find nice ‘crystals’ so I often made my own with quite the effort. I really like these little glass nuggets and have even asked a windshield repair shop to save me their sweepings. They also tend to be in nice blueish shades.
My favourite concrete; Rapidset Cementall mix can be adjusted to work quite dimensionally for this project and the fast curing time is even better! It is a very fine, non-aggregate mix that will finish super smooth if the mold is also smooth.
- Rapidset Cementall (or similar strong fast-setting mix)
- Mixing vessel and stir tools
- Gloves and Dust Mask
- Various glass crystals (windshield or made)
- Mold (half sphere of flexible plastic) I use Tupperware vintage ‘Forget me Not’ tomato keeper
Since I’m a bit of an orb- crazy maker I am always on the lookout for things that can be used as a mold for concrete! Thrift shops are great for that or even craft stores since some types of sphere are used for Christmas ornaments and chocolate making. It is best that it’s not too brittle plastic and has some flex. You can also make your own over a ball shape as I did with this orb mold. It has lasted really well.
The beauty of the orb shape (perfect ball) is that you can reposition the orb in the mold as it always the same diameter, so you only really need a half sphere!
Mixing the concrete:
When mixing this mix; add the concrete to the water, it also uses less water than expected. I only mix small amounts as I usually only have less than 30 minutes working time in the warm summer.
If I let it sit for a minute it becomes even more malleable so that it can be formed. To slow the setting you can use super cold water.
When the plastic is quite shiny I do not need a mold release. If you like, some small amount of WD40 or an oil can help. Start with dollops of the mix and start adding the glass…
A bit of this and that…
The glass should be visible from the outside so keep some against the mold (do not press the concrete too hard into the glass)
Dipping the concrete into the glass also picks up the nuggets nicely.
Build up the side of the orb piece/dollop at a time. I like the irregular edges and try to have more than 3/16″ thickness.
Once I am within the half-shape I let it cure enough (about 1 hour). I can then loosen it out and reposition it in the mold.
The first half is ready to be added onto…
The Amazing Sphere shape!
Just like the large rock orbs, I shift it upwards in the mold so I can continue adding to the other side. Whenever adding ‘new’ concrete to set concrete make sure it is wet so that the old concrete does not ‘steal’ the moisture from the new concrete mix.
You can continue shifting the shape and adding. I like the natural rough edges and irregular opening. At some point your fingers will not be able to push the mix from the inside since these are not as big as the large orbs.
They can be used as ornamental table-scape pieces or even little planters. Feel free to paint or embellish but keep natural colours in mind. I can imagine these in a very zen rock garden… and since they are hollow and have holes they would not have issues with freeze/thaw.
I enjoy making these since the supplies are simple and they finish quick. I’ve often asked myself why orbs are so interesting… I’m not sure what the appeal is.
How lovely they ‘match’ natural live-edge wood! Stuff them with some little succulents or air-plants and you’d have an amazing planter.
Happy concreteing… If you want more orb projects or geodes. Working with concrete is not that scary, check out the tips & tricks.
These are fabulous! I can think of many, many used 😻😻😻. Thank you for your ideas, you’re Fab too!
I’m so glad there’s so many ideas! I can imagine them as a table centre piece, maybe for a wedding with white flowers. Oh, if you could see what I see in my mind! Happy making!
Love the website!!! Thank you so much .
Curious to how these would handle having a candle or tea candle in them? besides being hot to the touch would the heat cause any issues with the glass or the rapid mix?
There should not be any issues since both those do not burn. When concrete is used for firepits it can be a problem if the concrete has not cured properly. The moisture could make it explode. Even rocks in firepits can explode. Make sure it is well cured or use some battery lights… a string of the fairy lights would sparkle! These are similar
Love that glass! And have been known to pick it up from the side of the road. Hmmm – the techs are coming to replace my windshield this week – I was planning to save some for a friend with a rock tumbler. It comes out very nice, if a bit less sparkly.
Barb – you help me feel like a normal person!
Oh thank you! Everyone out there who chimes in also make me feel like a normal person! ‘Here’s to be creative!
Barb these are beautiful! Your talent seems to be endless. Thank you for all your brilliant ideas.
I really just credit it to allowing any ideas I dream up to have merit. I bet it comes from childhood where I was always encouraged to be creative. I try to instil that in my grandson…
Another gorgeous creation Barb. I wish concrete was so darn heavy. My arthritic hands just couldn’t take it but I would love to try making some of these.
I understand… I get guy at the store to put it in my trunk and then when I get home I carefully open and divide it into smaller sealed containers so I don’t so much dust and it’s easy to carry. There are smaller boxes of Rapidset Cementall but it costs more.
You have such beautiful hands for being a concrete worker! I love your work tried to donate. Some mix up I’ll work on it. I’ve learned so much from you. Keep up the good work.
Oh no, my hands are quite arthritic and fingers are crooked. But that’s from decades of all kinds of making! Thanks for trying to donate…
Has anyone tried cutting an old playground ball in half? Too flexible?
I tried using a basket ball cut in half and it was too flexible. The best mold I have is a silicone one made with the corn starch. It is quite stiff but flexible enough.