This weekend, I built a bullet-proof coffee table.

For years, I’ve had a three-foot by four-foot piece of bullet-proof glass that I removed from a bank while working construction there. I saved the glass, thinking that it would make an AWESOME table. Well, I finally got around to building it.

I cut pallet-racking cross-pieces to build a frame that would wrap around the glass. Pallet racks already have a 1.5″ indent in them to hold lumber, which was perfect for a supporting lip for the glass.

The legs were two-inch steel square tube, cut to 18″ long. After cutting the pieces, I tack welded the whole frame together, checked for square, and tested it against the glass. I then did all the welds, capped off the ends of the legs, and ground round the top corners.

After that, it was a coat of primer, a coat of 1980’s bank industrial beige paint, and laying the glass into the frame.

I still wanted to test how bullet-proof it was, but simply, and safer than with a gun. I did have a bowling ball handy! Check out the video for how I made an interesting pattern in the glass!

After I marked the glass, I thought it would look really cool backlit! Once it was dark, I put a temporary light behind the glass, and was very pleased with the results. The cracks light up great! I’ll now have to permanently wire up some lighting under it.

I have a full DIY build write-up on it at Instructables. In fact, it’s in the INDESTRUCTIBLE contest there, and I’d love to get your vote!

Oh, and can anyone stop over and help me move this table? It weighs a TON!

I found some old mohogany baseboard that had some aging varnish on one side and some old caulking on another.  After cutting two 18″ long sections, a few minutes of belt-sanding had them looking great.  I used a 1 1/4″ Forstner drill bit to bore 0.3″ deep pockets for the bottles to fit in.  I used one of our two laser cutters to etch the name/age/proof of each of the whisky sample on top, plus a congratulatory message on the reverse side.  To bring out the rich orangy-red mahogany color, I wiped on Beeswax / Mineral Oil .  Check it out close up, while imagining the symbolism of things getting better with age!

Video of Vectorized Laser PCB Fabrication

The next generation BADASS board was too big to fit through the card laminator, so I figured I’d try my hand at Tom’s laser etching method.  By using the trace program included with CorelDraw I was able to make a vectorized path for the board.  One pass takes about 5 min at 50% speed.

The equipment required is relatively simple: An aluminum tank that contains 5Lbs of CO2, a gas regulator, a hose ending with a locking Schrader air chuck, a plastic bottle, a bottle cap with a Schrader valve stem mounted in it and two hose clamps.  All of these items are visible in the photos below.

The aluminum tank and gas regulator are available locally at restaurant or homebrew supply stores, or online from places like beveragefactory.com or coppertubingsales.com.  Prices at these latter two places are $85 – $100 for the pair.  I filled the CO2 tank for $9 at a local beer retailer.  I purchased the locking chrome plated air chuck, the stainless steel hose barb connected to it, the hose clamps, and the steel wire reinforced hose from a local hardware store for $15.  The Schrader valve stems were purchased from a local auto parts store – they are fully chrome plated, and are sold as replacement car tire valve stems for $2 each.

I initially used standard industrial air hose fittings instead of Schrader valves, but ran into several problems.  Only one side of this type of fitting seals when the mating fittings are disconnected.  This means that after a liter is carbonated and the hose is detached from the plastic bottle, either all the CO2 in the hose leaks out, or some of the CO2 leaks out of the bottle.  Also, inexpensive industrial air fittings are either made of steel or bronze and begin to corrode due to exposure to the carbonic acid formed when the water is carbonated.  Chrome plated Schrader valves have neither of these problems, and are even less expensive than industrial air fittings.

The carbonation process is also simple.  I fill a plastic San Pellegrino bottle 80% to 85% full of Brita filtered water chilled to ~36 degrees (standard refrigerator temperature), I squeeze all the air out of the bottle and tighten the plastic cap with the Schrader valve onto it.  I fully open the CO2 tank valve, set the gas regulator valve to 55 PSI (typical commercial waters are carbonated to about 20 PSI), squeeze the locking Schrader air chuck, and lock it onto the bottle.  CO2 immediately begins to flow, and inflates the bottle instantly.  An audible hiss continues as the CO2 pressurizes the bottle, which I shake vigorously for 20 to 25 seconds, after which time the CO2 hiss has stopped.  The hose is then disconnected from the bottle, and the water is carbonated!

All these details are important to successful carbonation.  The empty space in the bottle (the 15% to 20% of the bottle that doesn’t contain water) is critical to allowing the CO2 to get and stay in suspension.  The amount of CO2 that is soluble in water increases with colder temperatures.  Squeezing out all the air allows for more CO2 to fit in the bottle.  Shaking the bottle increases the rate at which the CO2 dissolves in the water.  All of these factors make for more fizzy water (which is the goal, right?)

The taste of San Pellegrino can be more accurately replicated with the addition of minerals.  With the addition of 1/8 tsp of Magnesium sulfate (Epsom salts) and 1/8 tsp of calcium chloride, one achieves the 210mg/L of Calcium and 60mg/L of Magnesium that San Pellegrino has!  Both of these minerals are wine/beer brewing additives, and can be purchased from local homebrew supply stores.  Check here for more mineral additive possibilities, and the book “The Good Water Guide” for the mineral composition of most commercial waters on Earth.  I find that carbonating to 55 PSI rather than a more reasonable 20 to 25 PSI makes for so much more joy that I (and my kidneys) don’t miss the extra minerals.

If you want to make this setup at home, please follow these safety guidelines.  There are several which are very important, as a gas cylinder is somewhat dangerous, as its internal pressure is between 700 to 800 PSI, depending on temperature.   Carrying the cylinder by its valve is a bad idea.  The tank should be secured at all times so it doesn’t tip over and damage the valve.  When it is transported, it should always be upright and it shouldn’t be left in a car sitting in the sun, as the internal pressure will increase hundreds of PSI.  The regulator you purchase should have a pressure safety valve which releases at ~60 PSI to vent excess pressure and prevent your plastic bottle from exploding.  Similarly, your hose should be rated for higher than the pressure you intend to carbonate to.  You should never carbonate in glass bottles.

I measured the pH of my 55 PSI carbonated water, and found it to be 4.6, whereas the pH of Coke is a much more acidic 3.2, as shown below.  The pH of my water prior to carbonation was a perfectly neutral 7.0.