MAKING SEA GLASS IN A ROCK TUMBLER
It turns out, making sea glass in a rock tumbler was way easier than I expected. For my first batch, I simply used a few tablespoons of play-sand to sand down my glass, but then I purchased a pack of carbid grit and I found that harder, coarser grit helped speed the process of making glass shards into beach glass and also gave me more control over how round and frosty these gems turned out- just like my childhood memory of “mermaid tears.”
What You’ll Need:
Motorized Rock Tumbler – I use a $100 Lortone 3lb Capacity Tumbler for fast, professional results but reviewers indicate that with patience, this $50 rock tumbler should work.
GLASS (see below for tips on recycling glass. For hard-to-find colors, you can buy the colored glass chunks made for high end firepits in red, black, and colbalt blue, )
5 gallon bucket
2 large thick plastic bags (clothing storage bags work great)
a fry basket or a colander with big holes (turns out, fry baskets are perfect for sorting and shaking tiny glass fragments out from usable sea glass pieces)
cut-resistant work gloves
safety glasses (seriously, do NOT do this project without safety equipment)
shallow cardboard box (to contain small shards of glass)
grit (you can use sand, but a coarser grit gets the job done with less time and less electricity used. If you think you might also tumble rocks, try a variety pack of abrasive media, but for just turning a few loads of broken glass into sea glass, you can buy coarse abrasive media in 1lb packs.
Step 1: Find or Make Broken Glass
Source glass from thrift stores, recycling, or garage sales. Read my tips for sourcing colored glass. Wine bottles and liquor bottles can be used for making sea glass, although in my experience only the glass at the upper rim of the neck and the bottom of the bottle is thick enough to make pieces of sea glass that are substantial in size.
Step 2: Break the glass
This is by far the most dangerous part. Please be smart, safe, and glass savvy. Glass is pointy and dangerous, handle with extreme caution and with all appropriate safety equipment. And for the love of your eyeballs, do not skip protective eyewear.
A. Have the barrel of your tumbler open and nearby. Place the unbroken glass in a heavy plastic bag, then place that bag into another heavy plastic bag. Put on goggles and gloves and place the bagged object inside a cardboard box.
B. With goggles on, use the flat side of the hammer to strike the object until it breaks. Continue striking the large pieces until the pieces are somewhat uniform in the size range you desire for your sea glass products (remember, tumbling will make pieces a bit smaller!).
C. Carefully, with hands protected by cut-resistant gloves, dump the contents of the plastic bags into your colander or egg basket (over a safe receptacle). Tiny shards of glass will fall through the basket leaving the big chunks behind. (When I do this part, I work over a double-bagged trash can, to minimize cleanup) Gently shake the basket of glass till the small shards are removed, then with gloved hands manually move the larger chunks of glass into the barrel of the rock tumbler.
Step 3: Tumble
Use the instructions below for replicating the ocean’s sea-glass making environment in a rock tumbler
A. Add glass until the barrel of your tumbler is about 1/2 to 2/3 full of glass (I usually fill to 2/3rd of the way full) If you don’t have enough glass shards, you can add a few clean rocks. IMPORTANT: The 1/2 – 2/3 fullness is required for the contents to tumble instead of slosh.
B. Check the manual for your tumbler, but for my 3lb capacity tumbler, I used about 3-4 tablespoons of grit. The coarse silicon carbide grit I linked earlier makes the process go about twice as fast.
C. Add enough water to cover the glass and abrasive but DO NOT OVERFILL. (You want a sludgy tumble with each barrel turn, not a constant slosh).
D. Run for 3-5 days. After 48 hours you can pop the barrel open and take a look if you are impatient like me. At this point, you should notice some frosting on the glass and significant dulling of sharp corners. Continue tumbling until the pieces are evenly frosted with rounded edges. The longer you tumble, the more the final glass pieces will have the appearance of being very, very old sea glass gems.
Step 4: Sift and Clean
Separate glass from grit using water and a colander.
After a few days, your glass will be ready. To finish each round of tumbled glass, I hold my fry basket/colander over a bucket and gently pour the newly made frosted glass baubles from the tumbler’s chamber into the basket, allowing the water and grit to drip through leaving only the glass behind in the basket.
Take your egg basket, glass, and bucket to an outdoor area with a hose and hose down the sea glass, washing away all remaining grit and any grime picked up in the polishing process. (Do not wash the grit down your drains!)
TIP: Reuse the carbide grit by leaving the bucket of rinse water to sit for a few hours. Once the grit settles at the bottom of the bucket, you can carefully dump off the water and save your grit for reuse.
Spread your homemade glass gems on a clean, dry surface to dry (a towel or a cooling rack from your kitchen works great). Once completely dry, your sea glass is ready for any project you have planned for it!
Homemade sea glass is beautiful for home decor, jewelry and fused glass art