Breaking glass nicely
April 20, 2011 8:25 AM   Subscribe

I collect beach glass to make things. I've used a rock-polisher to create beach glass. I am looking for hints in increasing my yield from the rock-polisher, namely how to break bottles to get decent sized pieces.

I can't find enough beach glass for some projects during vacations to the shore. So I bought a rock polisher to make additional stocks of glass.

I then look for interesting colored beer/wine bottles (blues, different greens, some clear and some brown, would like to find a red one). I drink/empty them, clean out, then break up the bottles to feed the rock polisher.

My problem is how to break the bottles. I've tried scoring with a glass cutter tool, with poor results (very hard to score the curved glass - the tools is meant for sheets of glass). I've tried light force (tap tap tap until it breaks), brute force (hulk smash), pin-point force (hammer a nail punch like device onto the bottle).

All of those result in lots of tiny shards (glass dust), and few usable pieces (ie a real mixed bag of usable/unusable/break-again pieces). A usable piece (to me) is ~1x1inch square in size (with some margin of error).

I don't want to use sheets of glass, because the curves of bottles make more interesting objects.

So how does one break a glass bottle up nicely to get less waste and more usable chunks of glass ?
posted by k5.user to Sports, Hobbies, & Recreation (15 answers total) 3 users marked this as a favorite
Not sure if it will work on bottles, but when I used to break ceramic plates for making mosaics, I would wrap them in a towel and hit them with a rubber mallet. Maybe give that a try, on a non-interesting bottle first?
posted by rabbitrabbit at 8:56 AM on April 20, 2011

It's going to be hard because there are many variables (thickness and shape of glass will vary so much from bottle to bottle). It seems to me that it might be worth trying to fill the bottle with fine sand and then submerge it in the same sand until just a bit of the bottle is showing, and then hit that exposed point with a hammer, gently. I think if you can retard the chaos and force of the break (the sand) you can get the bottle to break 'less', in fewer pieces.

Worth a try, anyway.
posted by dirtdirt at 9:04 AM on April 20, 2011

First, do you know how to cut glass as a flat sheet? It's possible you're not doing a good job with the scoring (scoring too hard etc.) Once you have a sense of how to score glass effectively. You can buy specialized cutters for cutting bottles. I'm not sure why he keeps using temperature to shock the glass. If he knew how to use the hammer properly there's no reason he couldn't tap it into a clean edge. Learn to cut flat glass so you get a sense how to tap.
posted by If only I had a penguin... at 9:07 AM on April 20, 2011

Score deeply around the base of a heavy bottle and chip the end off. The crush the cylinder with a minimal amount of force - wrap it in a towel and give it a mallet-y whack or step on it.
posted by codswallop at 9:42 AM on April 20, 2011

I am wondering if using a thicker glass, like a champagne bottle, might work better.
posted by annsunny at 9:48 AM on April 20, 2011

Two suggestions, neither tried:
1. A vise. Wrap the bottle in paper / thick plastic, and crush slowly.
2. Just for the geekiness: implosion. Put a stopper in the bottle, weigh it down, place in a wire basket, and submerge until imploded. I don't know how deep the water would have to be; it might be quite deep, i.e., more than 100 meters.
posted by labberdasher at 9:52 AM on April 20, 2011

It's not you, it's the bottles.

Brewers have been succumbing to pressures to make their bottles tempered for safety reasons. Tempered bottles break into smaller, less dangerous pieces. The bottles end up being lighter, too, and fuel costs alone must now be near the point that changing to tempered pays for itself.

Find older bottles at dumps or estate sales.
posted by jamjam at 9:54 AM on April 20, 2011

The best way to break a bottle is to wrap it inside a large towel. Put the wrapped glass on the ground outside and tap it with a shovel. Wear thick gloves and dump the glass pieces out of the towel into a bucket. Carefully sweep up any broken glass that falls on the ground.
posted by fozzie33 at 9:58 AM on April 20, 2011

Here's an article by a guy that needed a lot of beach glass, he used a cement mixer. Sadly, no tips on bottle breaking.

Please don't use a towel as protection from broken glass. Tiny slivers of glass will get stuck in the fibers. Use a small blue tarp instead.
posted by Marky at 10:11 AM on April 20, 2011

Collect all those plastic shopping bags and use several layers of those instead of a towel. The key thing is to protect your eyes; wear safety glasses. Find a good flattish rock with some unevenness. It's harder to get chunks when something is on a flat surface. Rubber mallet is a good idea. I used a hammer to break up ceramic tiles.
posted by theora55 at 2:48 PM on April 20, 2011

Wrapped in a shirt or a few layers of plastic you can break a bottle into just a few pieces with a solid whack on a curb or cement stair.
With leather gloves and a mask or goggles it's very easy to break the larger pieces by hand.
If you do wrap it in fabric, leave the cloth outside or in your workspace, those little slivers stick around forever.
posted by gally99 at 6:10 PM on April 20, 2011

Response by poster: Thank you all for the ideas.

I've been wrapping the bottles in multiple layers of news paper and hitting with a standard claw hammer.. Hadn't thought to try my deadblow hammer (well, it's rubber, but not quite a rubber mallet).

I'll give as many suggestions as I have bottles a try this weekend. Guess I should start drinking now.
posted by k5.user at 6:21 PM on April 20, 2011

If you have friends in a rural zone, target practice.
posted by ovvl at 6:41 PM on April 20, 2011 [1 favorite]

I have heard that wearing a diamond ring with the stone pointing inwards, gripping a bottle and turning it in the hand is an easy way to score around a bottle. Cheap diamond rings may be found at a pawn shop near you.
posted by emilyw at 3:11 AM on April 21, 2011

You may want to try wrapping the bottle in duct tape. I would think it would stabilize the glass possibly making bigger chunks.

It should make the cleanup of the small shards easy too!
posted by lairc at 2:10 PM on April 21, 2011

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