A Carbide Lamp User's Guide.

By Frank Meloi.

"Why use a carbide lamp, when there are more advanced forms of lighting available?" There are many ways to answer this question. First, the carbide lamp is, quite arguably, the most versatile piece of lighting equipment ever conceived. Not only can you use it to find your way, but you can also cook with it, use it as an emergency heater, and mark the way out by writing with the soot it produces. Hell, you can even light your post-mine victory cigar with it! (Let's see you do that with your Wheat Lamp!) Best of all, is that the carbide lamp continues to be a cheap, dependable source of illumination. There are no heavy acid batteries to carry around, and the carbide lamp will run as long as there is carbide and water available. When you consider that a Wheat battery will only last a few hours, having a carbide lamp handy may mean the difference between life and death, if lost in a very large mine. Apart from this, carbide lamps are extremely rugged pieces of equipment. Stories abound of cavers dropping their lamps down deep crevices, and climbing down to find them unharmed. Probably just as important is the romantic aspects of owning a carbide lamp. These lamps, with their sleek, vintage lines, remind us of simpler days gone by. This record of versatility, dependability and aesthetics is what continues to endear these lamps to so many people.

What is calcium carbide?

Calcium carbide is a chemical compound formed by heating lime and carbon in an arc furnace. It is a hard, grayish, rock-like substance, and its molecular formula is CaC2. Calcium carbide reacts violently with water, producing acetylene gas. (Click here: http://www.youtube.com/watch?v=_Ny9LbH2Dhw to see a video of this reaction.) 1 gram of calcium carbide will produce about 349ml of acetylene.

A way to produce the chemical was first dicovered in 1892, by Canadian inventor Thomas L. Wilson, while working at the Wilson Aluminum Co. in Spray, North Carolina. Wilson was attempting to find a new, economical proccess for producing aluminum. What he developed, however, was a way of manufacturing a product that would have great, and far reaching, benefits for the industrial world.

From its inception as an industrial compound, calcium carbide was associated with lighting. Cities and towns readily adopted acetylene as a cheap, easily obtainable gas for the lighting of homes and streets. Carbide lamps were also used as bicycle lamps, and as headlights on automobiles. Today, the main industrial use of calcium carbide continues to be the production of acetylene.

Anatomy of a Carbide Lamp.

Although there have been hundreds of different patents for carbide lamps over the years, the basic principle remains the same. Water is dripped from a reservoir into a lower chamber in which carbide is kept. The chemical reaction occurs within this chamber, which is made airtight through the use of a gasket. The acetylene gas produced passes through a filter, and then on to a burner tip. A reflector placed around the burner focuses and condenses the light produced by this flame.

Now that we understand the basics of a carbide lamp, let's go over the individual components in greater detail. For illustration purposes, I have used my Autolite lamp. Almost every lamp out there (Justrite, Guys Dropper, Premier, etc.) have identical parts. The operation is technically the same, no matter what make of lamp you may own.

Fig. 1. An Exploded View of a Carbide Lamp:

The above illustration (fig. 1) is an exploded view of the Autolite carbide lamp, and serves to identify the many components of your lamp. You may feel the need to refer to this illustration, from time to time, while reading through this tutorial.

Step 1: Installing the filter assembly.

Carbide lamps were originaly supplied with felt filters. Although you may still use felt if you desire, it is, today, considered to be a poor choice. The main drawback with felt, is that it will clog if it becomes wet; and as anyone who has ever used a carbide lamp can tell you, a clogged felt can totally ruin your trip! When a felt filter becomes clogged, acetylene can not rise to the burner tip. It will instead rise through the water tube, percolate through the water in the reservoir, then out the hole in the water door. This is a watery mess that is easy to avoid. A good replacement for felt, and one that I use exclusively, is the Scotch-Brite scouring pad.

Using the old filter (or the felt plate, if the filter is missing) trace an outline on the scouring pad. Cut out this circle, and make a small hole in the center, just large enough for the water tube to pass through. I like to make my hole somewhat smaller than the diameter of the water tube, for a more snug fit. Voila! You now have a filter that will not clog, is easy to clean, and readily available. It is always a good idea to make as many as possible, and to carry spares with you whenever you go underground!

To install the filter assembly, follow the order in fig. 2. First install the filter plate. Make sure that the cup on the filter plate is facing TOWARDS you. Next, slide the filter media into place, followed by the filter retainer. The filter retainer should fit snugly against the water tube. If the retainer is loose, or slides easily, it may be neccesary to adjust the clips on the retainer inward, so that they make better contact with the water tube. You should NEVER operate your lamp without a filter in place. This increases the risk of a clog, and could, theoretically, cause an explosion. (Note: if you are missing any parts of your lamp, please see the "links" section at the end of this FAQ.)


Fig. 2. Installation of The Filter Assembly:

Fig. 3. With Filter Components Removed:

Step 2: Charging the Carbide Chamber.

Before using your lamp for the first time, take a moment to inspect all parts for leaks. Pay close attention to soldered joints, as well as obvious dents and dings. If a leak is found, please consult the repair section further on in this FAQ.

An effective (though unsanitary) way to check for leaks in the carbide chamber, is to simply place your lips around the threads and blow. If you feel that there is no air escaping, chances are that you have no leaks.

It is important not to use too much carbide when charging your lamp. Calcium carbide decomposes into carbide lime, which may be difficult to remove if there is too much carbide in the chamber to begin with. A good rule for filling your lamp is about half full. Pour the carbide directly into the carbide chamber (Fig. 4).

While some carbide users reccomend using a 35mm film canister as a means of both storage and measure, this is not good practice since variations in size exist between different makes of lamps. Another reason to avoid film canisters is that they can open easily in your bag. In a moist environment such as a mine, this is a danger to be avoided. I always keep my carbide in a small, shatter-proof, plastic jar, and make sure to keep the lid capped tight. I can then add more carbide as needed, by measuring it into my palm, then pouring it into the chamber.

Fig. 4. The Carbide Chamber, About Half Full of Carbide:

Once the chamber is full, install the rubber gasket on the rim. At this point you should check to make sure that both sealing surfaces (On the upper and lower parts of the lamp) are clean and smooth. Also inspect the gasket for signs of damage or excessive wear. A damaged gasket must be replaced. If a gasket leaks, the lamp may burst into flames when lit. Moistening your gasket prior to installation will aid in forming a good seal.

Now simply screw the carbide chamber into the upper portion of your lamp. Tighten it well enough to seal the lamp, but not so tight as to damage the threads. It is possible, if you over-tighten the lamp, to crack the threads!

An important thing to keep in mind is the disposal of spent carbide. While it was common for miners to simply dump their spent carbide in the mine, we should avoid damaging the complex ecosystems found in abandoned mines, by doing the same. Always carry a few zip-lock bags in your pack. When your carbide is spent, simply dump the sludge into the bag and pack it out with you.

The consistency of spent carbide (carbide lime) is dependent on the amount of water used. If you are running your flame high, you will inevitably be using water at a faster rate. Typically, carbide spent in this manner will be quite fluid, almost like a slurry. When conserving your carbide, by keeping the flame low, less water is used. Carbide spent in this manner will have a more clay-like consistency, and may be difficult to remove. When cleaning the chamber of spent carbide, please bear the following in mind: NEVER use a sharp object to scrape out the lime, and NEVER tap the chamber on a hard surface. In using a sharp object, such as a knife, you run the risk of puncturing the carbide chamber. If you are underground and this happens, you have a potential catastrophe on your hands. Tapping the threads against a hard surface may deform them to the point where they will no longer screw in to the upper part of the lamp. A better way to remove stubborn carbide lime is to use a popsicle stick, or some other blunt object. If you absolutely must tap the chamber, invert it in one hand and tap the bottom with the other. This works well, and spares your valuable lamp from possible damage.

Step 3: Filling the Reservoir With Water.

Fig. 5. Filling the Reservoir:

Once the carbide chamber has been filled, and the lamp has been put back together, you may fill the water reservoir. On top of the reservoir you will see a regulator dial (Figs. 6&7). Make sure that this dial is in the "Off" position before filling. To fill, simply open the water door and fill to the top, leaving enough room for the door to close.

Step 4: Lighting Your Lamp.

Now that your lamp is all filled up, it's time to light it. Turn the regulator dial to half-way between the on & off positions. Hold it there for a second or two, to get the carbide started (fig. 6). Immediately return the dial to its lowest setting (fig. 7). Now observe the burner tip for signs of gas. You will be able to hear and smell the gas escaping from the tip. If there is no gas coming out of the tip, you have a clog. Another sure sign of a clog would be gas and water percolating through the water door. Turn the lamp of and determine the source of the problem before continuing. If the gas is flowing, grasp the lamp in one hand while cupping the other palm over the reflector. Position your palm so that it is in contact with the spark wheel on your lighter. Wait a few seconds for the gas to build up, then quickly slide your hand away from the reflector, sparking the wheel as you slide. If done properly, the trapped gas will ignite with a pop, and your lamp will be lit. To see a video of the proper procedure, click this link:
http://www.youtube.com/watch?v=TMguFRdZvDo

Once the carbide lamp is lit, it will be neccesary to adjust the water dial to regulate your flame. I find that a flame of about 1 & 1/4" is ideal. You can increase or decrease the drip accordingly, to suit your lighting needs. Just bear in mind that the higher the flame, the faster the carbide will be spent.

Fig. 6. Turn the regulator dial to 50% maximum for a second or two to start the carbide...:


Fig. 7. ...then immediately turn it to its lowest setting.
(Note, this picture is incorrect as it depicts the dial turned to its highest setting. You will need to set the dial to the first increment after the "Off" setting.)


Some people like to start the carbide by spitting into the carbide chamber before lighting. There is evidence to suggest that this method saw wide practice among miners during the carbide-era. Admittedly, the author himself uses this method.

Caring For Your Carbide Lamp

In order to keep your carbide lamp in good operational condition, and to avoid any disappointments in the field, it is important to always keep the lamp perfectly clean. Always clean your lamp as soon as you get home from the mine. First, disassemble the lamp completely, then rinse away all traces of spent carbide. Remove the burner tip, and inspect it carefully for blockage. Use a tip reamer (available through Bob & Bob's...see links section) to clean the tip of carbide soot.

Using a toothbrush, give all parts of the lamp (inside and out) a good scrubbing under warm, running water. Rinse out the filter to remove any traces of lime, then scrub both the retainer and the filter plate. Before setting the parts aside to air-dry, inspect the Drip-mechanism, gas tube, and threads for lime deposits or blockages. If you encounter any stubborn deposits, it may be neccesary to scrub with vinegar, or Lime-Away (make sure to follow all manufacturers safety precautions). If the lamp is sufficiently clean, pat down all surfaces and parts with a soft cloth and leave them out to air-dry. Once the lamp is dry, reassemble it. Every second cleaning, use Lime-Away to ensure that no lime build-up ever forms on your lamp.

To clean the reflector, simply wipe it with a soft, damp cloth. Glass cleaner works well for stubborn deposits, but take care not to scratch the nickel plating on the reflector. Your reflector must be kept shiny and clean to assure maximum light output.

If these directions are followed faithfully, you should get a lifetime of dependable service from your lamp.

Renovating an Old Carbide Lamp.

If your carbide lamp happens to be in poor shape, it is usualy quite easy to restore it back to working condition. The only reasonable excuse for not being able to restore a lamp, would be cracked threads in the upper part. This type of damage is often too severe to repair, and results from tightening the lamp too tight. Although cracked threads on the carbide chamber are pretty bad too, I have seen examples where this type of damage has been successfully repaired.

The first thing to do is to conduct a complete assessment of the lamp's condition. Take the lamp apart and inspect both the inside and outside. Pay close attention to dents and dings, as these may harbor pinholes that would cause leaks. Look for missing solder, holes, etc. Test the water regulator to see if it moves. If it doesn't move with firm but gentle pressure, that is a sign that lime has built up and hardened in the water tube. NEVER FORCE A SEIZED REGULATOR DIAL!

Make a list as you go of all of the areas that need repair, or attention. Once you have finished inspecting the lamp for defects, you can then make a decision on whether or not to restore it.

If you do choose to restore your lamp, here are some tips organized by topic:

Drip Mechanism.

The drip mechanism is the "engine" of a carbide lamp. If the drip mechanism doesn't work, neither will the lamp...PERIOD. Understanding this, we need to take steps to ensure that we have a properly functioning drip mechanism. When buying a lamp at an antique shop or flea market, always take it apart and inspect the entire drip mechanism. Make sure that the water tube is not bent or damaged in any way and that the regulator dial turns smoothly. If it doesn't, don't buy the lamp.

To see a video of a properly functioning drip mechanism, click on the following link: http://www.youtube.com/watch?v=VpZf1r7Qvp0

Let's say though, that you have a lamp with a drip mechanism that is seized, but has no apparent physical damage. It may be possible to restore the lamp using the following methods:

1: Take the lamp entirely apart and soak the top portion in a solution of household vinegar. Open the water door and immerse the lamp completely. You will notice that the lime deposits will fizz when they come into contact with the vinegar. Wait until all of the fizzing has stopped, and remove the lamp from the solution. Test to see if the regulator functions. If it does, procceed to step 2. If it doesn't, you may need to soak the lamp for a longer period of time.

2: Once you have convinced the regulator to function again, push the dial all the way over to the "on" position. This will expose most of the ball-valve at the base of the water tube. Using a toothbrush and Lime-Away, scrub the water tube and ball-valve thoroughly. Scrub until all of the lime scale has been removed. Rinse under warm running water periodically, and continue scrubbing with Lime-Away until the water runs clear.

3: Once the regulator moves freely, you should test the ball valve to ensure that it works. Fill the reservoir with water and turn the dial fully to the "Off" position. Hold the lamp level and watch for leaks. There should be no drips from the water tube. If there are, you may need to repair your ball valve.

4: To repair a leaking ball valve: Place the lamp upside down in a bowl of cool water, so that only 1" of the water tube is sticking out. Make sure that the regulator dial is in the "Off" position. Using a blowtorch, gently heat the solder around the ball valve to loosen it. Once the ball is loose, push it firmly against the water tube to form a seal. When the solder hardens, your valve should function properly again. It may be neccesary to add more solder. Always remember to use flux when applying new solder.

Note: When performing this procedure, it is important not to overheat any part of the lamp. Since these lamps are held together entirely with solder, it is possible for your lamp to come apart, if overheated. While a bowl of water provides limited protection from this, it is by no means a complete safeguard. Apply the flame only briefly, and work quickly to avoid any mishaps. Remember that old solder contains lead! Take all neccesary precautions when working with lead.

Repairing Leaks.

It is not uncommon to find an old carbide lamp with a leak. These are easy enough to fix. If the leak is along a soldered joint, simply apply flux and add more solder. Depending on your soldering skills, this type of repair may be unnoticable. Actual holes and cracks may also be repaired, but will always be noticeable. My philsosophy, however, is that a serviceable lamp is a work of art in and of itself. I wouldn't reccomend that someone take an unfired lamp in "museum" condition, and use it in a mine. A lamp such as that deserves its place on the shelf, to be admired when company comes over. A workhorse lamp, on the other hand, has most likely seen many years of work before it came into your possession. Dents, scars and other imperfections can be an asset to a lamp such as this. Like scars on a person, they are signs of character that speak of a life of hard work. Therefore, don't fret too much about the appearance of a lamp, so long that it is serviceable. If a lamp works well, or can be made to work again, it's worth its weight in gold!

To repair a pin hole, simply brush on some flux and apply a drop of solder. If the hole is more substantial, or if there is a piece of brass missing, you may need to rebuild that part of the lamp. Purchase a small piece of sheet brass from the hardware store, and cut it somewhat larger in diameter than the hole you are trying to repair. If the hole is in the carbide chamber, apply the patch to the inside, and solder around the edges both inside and outside. If the hole is on the top portion of the lamp, you will need to patch it from the outside. Although this type of repair is not cosmetically attractive, it will result in a perfectly functional lamp. Fig. 8 shows a carbide chamber with an old repair. While not beautiful, this lamp still works quite well.

Fig. 8. Old Repair to the Carbide Chamber:


Cracks are repaired by pushing together the parts to be soldered, and applying a bead of solder to both sides. Wrapping your lamp in wet cloth (so as to avoid marring it) and using a vise should simplify this procedure. Cracks in the upper part of the lamp (female threads) are more difficult to repair, but not impossible.

Changing the Tip.

The burner tip on your lamp requires a large amount of attention and maintenance. It is neccesary to remove it, from time to time, to clean the lamp and inspect for blockages. A tip reamer (fig. 9) should be carried at all times to keep the tip clean and clear of obstructions.

Fig. 9. A Tip Reamer:

To use the tip reamer, gently push the thin wire through the hole in the tip. Make sure that the wire is held as straight as possible during this procedure. The object is to snake the wire through the hole, removing soot deposits, and other blockages, as you go. It is easy to wear down the tip when reaming, so ream carefully. Some reamers come with a wire brush at one end. Use this brush to gently clean soot from the outside surface of the tip.

Inevitably, your tip will need to be replaced. You can judge when it is time to replace your tip by the action of the flame produced. A good tip will produce a consistent and narrow flame. If your flame is wide, or oblong in shape, it is time to change the tip. Likewise, a large, short flame is a sign of a bad tip.

Figs. 10 & 11 represent the method employed to remove a tip. The example used is an autolite, but most lamps are the same. The tip is held in by friction, and is not threaded in any way. To remove, simply turn the tip (in any direction) with a wrench, while gently pulling towards you. To replace, just push the tip back in place and tap gently (take care not to deform the gas tube!).


Fig. 10. To remove the tip, turn it gently with a wrench...:


Fig. 11. ...then pull it towards you.


Restoring the Finish.

There is a vast difference between a dirty lamp, and a polished one. While many may argue against polishing an antique carbide lamp, I recommend polishing it if you use it regularly. A clean lamp just LOOKS better than a dirty one. It's that simple. A rare or collectible lamp, however, should be left as it is. A patina acquired through the years is not only beautiful in its own right, but may actally add to the value of the lamp. Most carbide lamps are made of brass, and take a polish quite well, with one known exception. The Premier lamp, although brass, has a coating of gold colored paint on it. This lamp should be cleaned with soap and water, but you should never use solvents on one, as this would strip the finish. Figs. 12 & 13 show the difference between a polished and a dirty lamp.

Fig. 12. A Dirty Autolite, as Found.


Fig. 13. A Restored and Polished Autolite.


The first step in polishing a lamp, should be to thorougly clean the interior of lime deposits. Supposing that you have just bought a used lamp at a flea market, this is almost always neccesary. The best way to do this is to fill the carbide chamber with Lime-Away and let it sit overnight. The next morning, dump out the Lime-Away and (using rubber gloves!) scrub the inside with a toothbrush. You will notice an extraordinary amount of black sludge coming up. Keep scrubbing and rinsing under warm running water untill the water runs clear. You may use the same method to clean the upper part of your lamp, but you will need to prop up the lamp so that it stays in an inverted position overnight.

Once the inside of your lamp is clean, use brasso to remove the tarnish. If the tarnish is severe, it may be easier to apply the brasso with a toothbrush and to scrub. This is the most labor intensive part of a lamp restoration, but stick with it until you get all of the tarnish off! Once you have removed the tarnish, follow up with a product called Nevr-Dull. Nevr-Dull will put a mirror finish on your lamp, and there is NO substitute for it. It is an absolutely amazing product! You can purchase Nevr-Dull here: http://www.nevrdull.com/ After polishing with the Nevr-Dull, buff out with a soft, dry cloth. Congratulations! You should now have a lamp that would make anyone proud.

Links for Carbide Lamp Users:

Replacement parts for your carbide lamp can be obtained from Bob & Bob's Caving Supplies. The folks at Bob & Bob's are very knowledgable and personable and will ship your items quickly!
www.4bobandbobs.com

Although Calcium Carbide has become increasingly more difficult to find, there are some reliable sources still out there. These are the most readily available sources:

http://www.ray-vin.com/

http://www.calcium-carbide.com/

http://store.karstsports.com/mingradcalca.html

As for lamps, there is (unfortunately) only one manufacturer of Carbide Lamps left, and that is JK Dey & Sons in India. They produce what seems to be a serviceable lamp, but I have never seen one of them up close. Here is a link to their site:
http://www.jkdey.com/

A profusion of used lamps can always be found on Ebay. They usualy tend to be overpriced, but if you strike out at the flea market you can find one there.