Sea glass is a type of rare mineral that’s created when ordinary beach sand becomes weathered by the salty waves and wind over many years. While the murky, frosted glass is a naturally-occurring composite, it’s also possible to make your own by replicating the conditions under which it forms. You can do this by taking ordinary scrap glass and weathering it artificially in a small rock tumbler for 4-5 days. By the time you’re done, it will look as though you’ve pulled it straight from the surf on some distant shore.
Purchase a rock tumbler.
In order to create sea glass in your home or laboratory, you’ll need to have a way to weather large chunks of glass into pieces that more closely resemble those you would find on the beach. A basic rotary tumbler will work well for this purpose. As the tumbler turns, it will grind, smooth, and polish the glass.
The rock tumbler itself will be the most expensive part of your project—these contraptions can be obtained from specialty suppliers online or anywhere that natural science laboratory equipment is sold, and may cost anywhere from $50-$300.
Rock tumblers come in a variety of different sizes. The higher the capacity of the barrel, the more you’ll be able to tumble at once. A standard-sized tumbler holds around 2 pounds (32 oz) of raw materials.
Select a handful of raw glass pieces to tumble.
This raw glass is known as “rough,” and will go on to assume the cloudy, weathered finish characteristic of sea glass. For best results, pick out pieces that are at least 1⁄4 inch (0.64 cm) thick and about as big around as a quarter (or slightly larger). Glass that’s too thin will be worn away until there’s virtually nothing left.
Landscaping glass or “cullet” (recycled industrial glass) is perfect for making sea glass. You can usually find these materials at home improvement centers.
It’s not recommended that you break glass yourself for tumbling. Not only is this dangerous, it will more than likely produce small, unimpressive sea glass.
Fill the barrel of the tumbler ⅔ of the way full with glass pieces.
Remove the lid from the barrel and add the glass directly to the bottom. For best results, it should be mostly full, but still have enough room inside for the rough to shift around.
If you have a large quantity of rough you want to transform into sea glass, it may be necessary to tumble it in multiple batches.
Always start with a clean tumbler, making sure all traces of grit or leftover fragments from the previous batch are gone before you add new materials.
Pour in 2 level tablespoons (about 25g) of coarse grit.
To tumble glass, you can either use silicon carbide grit or ceramic pellets as a filler. The coarse grit will spread through the empty space around the rough to weather it in all directions. Both silicon carbide and ceramic media can be purchased online or through suppliers who cater to educators in the natural sciences.
Without filler, the raw glass pieces would smash into one another inside the tumbler barrel and become shattered or scratched.
Avoid filling the barrel more than ⅔ of the way. If it’s too full, the materials inside won’t have anywhere to go, which means any time you spend tumbling will be wasted.
Add water to the top of the rough.
Run cool water into the barrel until it just begins to filter up through the glass pieces underneath the coarse grit. A little moisture is needed to smooth the glass as it tumbles. This process is similar to the one that causes sea glass to form naturally.
Be careful not to overfill the barrel, or you could end up with a big mess on your hands.
Add ¼ tablespoon (roughly 3.6g) of baking soda.
Some types of glass release gaseous byproducts when they’re ground up. After a few hours or days, it’s possible for these gases to build up inside the barrel, which could create pressure leaks or send glass particles spraying out when you remove the lid later. The baking soda will absorb the gases, limiting the pressure inside the tumbler.
Keep an eye on your rock tumbler as it turns. If the barrel looks like it’s bulging, remove the lid momentarily to let the excess gas escape.
Baking soda isn’t an essential component for making sea glass, so there’s no need to go out and buy it if you don’t already have some. However, it’s a good precaution to take, and could help prevent an inconvenient mishap.
Seal the tumbler.
Once all the individual components are inside the barrel, put the lid in place and twist it until it’s secure. If your tumbler barrel features any additional seals, clamps, or clasps, double check that these are fastened as well.
Turn the barrel over to inspect for leaks before you begin tumbling.
Set the barrel in the electric tumbler base.
Turn the barrel sideways and fit it into the open slot in the center of the unit. Make sure the knobs on either end are properly lined up with the vertical supports on the base. Once the barrel is oriented correctly, press it until it sits flush against the belt or rollers.
Most rock tumblers feature a horizontal construction, but some revolve in a more upright position. These types of tumblers may need to be inserted onto a separate spoke in order to secure them.
When you activate the tumbler, the mechanism beneath the barrel will create continuous traction, causing the barrel to spin.
Let the tumbler run for 4-5 days.
Switch on the tumbler unit. The barrel will begin revolving at a slow speed. Inside, you’ll be able to hear the various materials colliding with one another over and over again. The tumbler should be left to run continuously for at least 4 days.
Record the exact time and date that you began running the tumbler so you’ll know when you need to stop it.
The constant movement inside the barrel will be a little loud. It may be a good idea to do your tumbling in the basement or garage, or somewhere else where noise won’t be as much of an issue.
Check the progress of the glass.
Turn off the tumbler and remove the lid. Select a couple pieces of tumbled glass and hold them up to the light to evaluate their new physical characteristics. They should be much smoother and have a soft, cloudy quality to them.
Wait until the end of the 4-5 days to see how the rough is shaping up. In the meantime, leave the tumbler to run uninterrupted.
The longer you weather the glass, the smoother it will become. As a result, overly refined sea glass won’t look as authentic.
Rinse off the tumbled glass.
The combination of moisture and grinding minerals will produce a watery mud inside the tumbler barrel. It will therefore be necessary to clean the tumbled glass before you inspect it. The best way to do this is to transfer the pieces to a colander or mesh strainer and wash them over a bucket.
Do not pour the muddy water down the drain. It will quickly re-solidify inside the pipes, clogging them and wreaking havoc on your plumbing.
To dispose of the liquid grit leftover from tumbling, take the bucket outside and dump it in the grass.
Continue tumbling the glass until it achieves the desired appearance.
If you’re satisfied with the look of your artificial sea glass, clean off the remaining pieces and put them on display. If you’d prefer your glass to have a clearer, more polished look, load it back into the tumbler and run it for an additional day.
Natural sea glass is somewhat rough and murky, with a sort of “frosting” along the outer surface.
Adding a small amount of TXP aluminum oxide to your final load can lend your tumbled glass a much more brilliant, polished finish. Aluminum oxide and other rock polishes are often sold by mineralogy suppliers, as well as hobby websites that cater to rock tumbling enthusiasts.
Categories: Hobbies and Crafts