This post details how I made the garden ball pictured above, using a glass globe from an old pendant light fixture. You likely don't have one of those handy :) , but a little thinking outside the box and you can come up with other unique 'molds' to make bases for your own personalized garden art.
First- some general supplies:
- Some sort of 'mold'. Ideas- glass bottles, plastic containers such as milk bottles, takeout food containers... IMPORTANT: If you use a plastic form, you must have an opening wide enough for the cured concrete to be removed through. For milk jugs, cut off the entire top before adding concrete mix. The opening needs to be as wide as the widest part of your shape.
- concrete mix
- eye protection!, hammer, prying tools
- glass nippers
- scrap stained glass- often local stained glass shops will sell scrap by the pound or ebay and etsy both often will have listings for scrap.
- thin set mortar
Add concrete mix slowly and tap occasionally (with your hand!) to raise air pockets. Don't want to break that glass yet! If your shape includes thinner sections, you will want to reinforce them with hardware cloth sections embedded in the center. See my stepping stone instructions.
If you use a plastic form, you can unmold, carefully, usually after one day.
If you use glass, WAIT a minimum of 10 days for the concrete to cure before breaking glass. Full cure is at 30 days.
Be sure to wear eye protection when breaking the glass off! I used both the hammer and the knob end of a glass scorer to break the glass in sections. Old dental tools and flat blade screwdrivers worked well to pry off sections.
Now that you have your blank concrete 'canvas', have fun creating!! I used the glass I removed to make the white flowers on my garden ball. They were especially pleasing to work with because the glass was curved and fit nicely back on the ball. I used thin set mortar to attach my glass. This is a weather friendly glue though if you live in a freeze zone, mosaic art lasts longer if brought inside in winter.
For adding flat glass to curved sections, smaller pieces fit around the curves better- and are less hazardous! Use extreme care when handling your piece as there will likely be sharp exposed points and edges. Grouting will minimize this.