Introduction: Rebuild a Carbide Lamp

Carbide lamps have been around since the late 1800's and are still lighting the way in many mines and caves across the world to this day. While the introduction of LED's is changing the scene, these wonderful old lamps are still functional, practical and useful. (This isn't a polish-them-up-and-make-them-pretty Instructable but rather a get-them-working-again Instructable. Polishing metal isn't too mysterious if that's what you're after.)

With a little creativity they can also serve purposes beyond what most flashlights can achieve. There's also just something cool about having a lamp that makes its own fuel via a chemical reaction. There are a lot of these old lamps to be had, and many that may look down-for-the-count can be resurrected with a relatively small amount of time and effort.

If you are looking for a lamp, there is a good article at I do think they are a little prone to writing off usable lamps as throwaways or bad equipment when many can be repaired or tweaked a little and used just fine. These are not complex machines once you understand them but they can be finicky and they do burn acetylene. So, be careful.

I like old Auto Lights and Guys Dropper lamps, but there are a lot of types to choose from. The only things I really avoid are lamps with plastic parts and Butterfly/Safesport or Minex brand lamps. Though, the Mike Light is a thoroughly modern lamp made from plastic and it seems to work well. Really popular with the Amish of all people. Good endorsement though. Those guys like their stuff to work. In the end it's all personal preference and even a bad lamp can be good for parts or tweaked and upgraded into something worthy.

This Instructable will be updated. It turned out to be a bit more complex than I had originally planned. I've tried to note where certain things will be added or amended but please let me know if something is unclear or confusing so I can answer your questions or adjust the Instructable.

Step 1: General Disassembly

Taking apart an old carbide lamp requires some degree of finesse. They are usually brass and therefore bend and break easily, but within a certain range of care they'll last indefinitely. So be careful and don't get heavy handed.

Most parts should come free with just your hands or very gentle use of tools. Using something like pliers or a multi-tool is probably going to mar or score the metal. Avoid that and use small adjustable wrenches or box end wrenches. You can also use screwdrivers on some things once you get a feel for what you are doing.

Just look at your lamp and note where it comes apart. A wing nut on the reflector, finger tight cap on the striker, small retaining nuts here and there, and a base shaped for hands to grip and turn. Easy enough.

You may have to deal with corrosion as well. Don't use a wire brush, it'll scratch up your lamp. Try soaking it in some white vinegar or maybe just running it under hot water. It shouldn't be too bad.

Note, the bottom of the lamp will most likely contain residue that has oxidized into calcium carbonate. Harmless and good for your lawn. It might also still contain volatile calcium hydroxide, aka, caustic lime. This can cause serious chemical burns. Be careful. If you think the lamp has been operated very recently avoid getting the powdery residue on your skin. This is probably unlikely with anything you will obtain from eBay or an antique shop, but chemical burns are really annoying so be careful. Once the residue has had some time to oxidize it becomes harmless enough to dump on your garden and actually do some good.

Step 2: Check the Drip Mechanism

The drip mechanism is pretty simple on most of these lamps. To check it just put water in the top chamber while the bottom of the lamp is removed. With the control lever or nob set in the on position it should simply drip water like in the video and photos. Not too complex. If the control lever/nob has a lot of play in it you might end up with problems. The water may drip too fast, potentially dangerous, or might let gas leak back up into the water chamber, non-functional. 

You can see the valve functioning in the video. I just made sure it would both drip and close. 

It's probably best to use some sort of filtered water in the lamp but any water will do in a pinch. Cave water works just fine as does rain water. Note that particulates will possibly permanently clog your water valve and water in caves is pretty much universally high in mineral content. 

I have yet to deal with a broken or loose valve so I can't advise on a fix other than salvaging parts from another lamp. The people I know who use these lamps that have encountered a loose valve suggest turning those lamps into art. Probably more creative uses for a dead carbide lamp but you get the point. 

Acetylene can be dangerous. Don't risk injury. Too many old lamps laying around to mess with a faulty one that can't be fixed. 

All of this comes with the caveat that if you are good at brazing and pipe sweating you can repair most any of these lamps. Even things like cracked bases and loose gas tubes can be repaired if you know how. Unfortunately if you don't and try without proper instruction you are likely to set your head on fire. ...literally. 

Please use caution. 

Step 3: The Reflector

As already mentioned, your reflector will most likely be held on by a wing nut. Just unscrew it and it should come right off. 

That nut also sometimes holds the flame tip in place (where the gas jets out). Don't lose it. Many are simply slip fit in place. 

One trick you can use to keep your flame tip in place is to very lightly coat the part that fits in the gas tube with tooth paste. This acts as a water soluble glue of sorts and makes for a decent fit. It's an old caver's trick. Miners probably know better. 

The metal cup that is mounted behind the reflector will also likely fall off at this point. Don't lose that either. Again, hard to replace. 

You can clean the reflector with vinegar or WD40 or whatever works, just avoid abrasives that will score or dull the reflector. Shiny is good. 

The next step explains how to remove and repair the flint striker. 

(Note, many old lamps will be missing their reflectors. There are a couple solutions to making a new one. I'll post them at some point in the future.) 

Step 4: Rebuilding the Flint Striker

Many of the vintage carbide lamps you find will either be missing the striker or it will be stuck/frozen. If it's all there you can probably rebuild the striker and replace both flint and spring with parts from a common BIC lighter. 

Gently remove the retaining cap from the back end of the striker. This will open the tube that contains the spring and the actual flint if it's still there. Set these things aside in a safe place where you won't lose them. The flint and spring are easily replaceable, the cap is not. 

You can rebuild a cap from a nut that matches the threads of the tube but It's best to avoid it if you can. 

Once you've got everything out of the striker tube go ahead and take off the retaining nut and remove it from the reflector. If you try to work on it while it's attached to the reflector you'll likely bend your reflector. Again, something that can be replaced but better to just take care of it. (I'll add an additional step showing how to build a new reflector once I get the parts or run across a lamp that needs one.) 

You can buy Zippo flints for to use in these strikers and they work great but I couldn't find any the day I worked on it. So, I just took one from a BIC lighter. You simply pull the metal cover off of the disposable lighter and then carefully pry out the striker wheel. The spring is pretty stiff in these things and it'll shoot the flint across the room if you aren't careful. 

You will most likely get "two" flints for your lamp out of each lighter. The ones from the lighters are longer than you can use for a lamp so just cut it in half. I wrapped the cutters and flint in a napkin so I wouldn't lose the pieces. Cuts pretty easily.

If your spring is shot, chances are it might be, just take the spring from the lighter and cut it to fit. No exact way to do this, guesstimate. You ought to get at least two replacement springs out of it. Springs from ball point pens work too. 

Once you have cleaned out all the stuff that is preventing the striker from turning you will likely need to clean it up with some steel wool or a brush. I used a Dremel and a screwdriver.

Once it's clean and spinning freely you can put the striker back together and try it. If it sparks you can then re-install it in the reflector. If not you might try either turning it around or cleaning the striker wheel. The strikers are often designed to spark in one direction, so if you have it backward it may not spark or only do so weakly.

If you absolutely had to, you could build a new striker with some brass rod stock and some lighter parts. You'd really only need a drill press and a hack saw or file. Maybe in another Instructable...

Check out the AVI of the rebuilt striker in action. 

Step 5: Clean the Burner Tip

The opening in the burner tip can be somewhat fragile if you use the wrong tool. You can purchase a special tool like the one in the photo or you can use a piece of small wire. Old phone wire is about right but the tools are usually just a few dollars. 

Just don't force anything and don't use something that will chamfer out the hole or open it up more than it is. I checked this one simply by blowing through it. While it didn't need much cleaning this time, it will in the future. Best to be prepared to do it. You'll want to carry something to clean the burner tip with you when you use the lamp anyway as they can become clogged during use. 

You can order replacement burner tips online but I have no idea how you would make one as the hole in the middle is extremely small. Probably a similar process to making pinhole camera lens plates but I couldn't say for sure. 

I'll try to post a DIY cleaning tool at some point. 

Step 6: Replace the Felt Filter

This is pretty simple. You gently pull the felt spring off of the water valve stem and then remove the felt filter. It helps to turn the felt spring as you pull it from the stem. 

You can buy new felt filters but you can just as easily cut a new one using the old one as a template. I intend to try a poly-felt filter at some point but the old ones are wool. You could just use a piece of an old army blanket or a hunk of a worn out coat. I haven'y tried felt from a hat but suspect it might be too dense. (Give it a shot, only one way to find out!) Some people also use Brillo pads or even foam sponges. I bought a 1/4 yard of wool felt at the time of this writing for about $9(USD) and will likely have filter material for a long time. It's also a good idea to cut extras to carry with you. If the filter gets wet the lamp won't work very well. You can either dry your filter or simply replace it if you have spares. 

There should also be a felt plate, just a thin metal plate with holes in it, that goes between the felt filter and the top of the lamp. If it's missing you can just cut one from a piece of perforated metal from the hardware store or scrounge something laying around. 

The lamp I used for this Instructable had two plates. Not sure if that's standard in some models, probably only needs one but I went ahead and used then both.  

Step 7: Get Annoyed Hand Cutting Filters and Make a Pile of Them With an Epilog Laser Cutter

OK, so I realized I needed more filters and got annoyed at the idea of cutting a bunch by hand. As mentioned earlier, you can buy these filters if you can find them but that's getting increasingly hard to do. Luckily thanks to modern technology lending a helping hand to heirloom technology you no longer have to worry about that. I'm into heirloom technologies and doing things in traditional ways but if you have a laser cutter you should use it! 

In this case the Epilog(and Randofo) probably saved me an hour or two of work and made a far more precise filter than I ever would have been able to by hand. 

I'm just condensing this into one "step". Those of you who know how to do this and have access to a laser cutter will be able to do it anyway and those who do not will now have everything they need to have a pile of felt gaskets custom made in a variety of colors by Ponoko

The screen shots are of both the design in Corel Draw and the print settings I used for the Epilog. The one I used is an Epilog Legend 75Watt model. I'm also attaching CDR and DWG (EPS coming soon) files of the design so you can burn your own. I have it set up for a dozen filters at a time. A dozen filters is probably all most people will ever need. I'll also try to figure out a way to either set it up so you can just order them from Ponoko if you don't want to bother with uploading the design and picking the material yourself. 

These filters are for the Auto Light lamps I was working on for this Instructable but should fit Guy's Dropper and some Justrite lamps along with Butterly lamps based on Guy's Dropper designs. They'll likely fit more but I can't say for sure. 

So, this is the actual step, use my design file to make some felt gaskets with your laser cutter or use my design file to order some from Ponoko. ...or just make your own. 

Note: EPS file coming soon!  

Step 8: Replace the Rubber Gasket

On most models there is a rubber gasket between the cup that holds the carbide and the upper part of the lamp. It's important! 

Without it you will probably have a poorly performing lamp or one that spectacularly bursts into flames as acetylene leaks out and catches fire. Entertaining and somewhat humorous but probably not a good thing. 

I tried something new on this one and cut gasket from bicycle inner tube to use in place of the rubber gasket that's supposed to be there. I quickly discovered you'd need at least three thicknesses of inner tube to get a good fit. 

You can also just go to your local hardware store, I went to our nearby Ace, and find an array of O ring style gaskets in the plumbing section. I tried a few types and found that the 1 1/2" X 5/16" round O rings worked well. They were all of  $.55 each. (A 1 1/2" flat dielectric coupler washer worked ok too but didn't make as nice a seal.) So, note that you can make your own but it's probably not necessary. Again, best to know what you CAN do as to opposed to what you probably will do. 

That noted you can still just get a scrap of inner tube and use the bottom chamber of the lamp as a template for the ID on the gasket and then measure and draw the OD or just get it close and trim it on the lamp. Either way will work. Just do what works best for you.

OEM gaskets can still be found on the web and in antique stores but I anticipate a time when they won't be. It's also always good to know how to repair these things in a pinch when you can't log in and go shopping.

Check the integrity of the gasket and the joint by running a flame near the seam when the lamp is full. If it catches fire you need a new/better gasket or you have a dent or crack in the base.

Another reason I like the old Auto Lights is because they have a one piece base with no seams. Harder to repair if they crack but harder to crack in the first place. 

Step 9: Reassembly

Putting your lamp back together is relatively straight forward and some of it will have been accomplished in the the other steps.

You might note that none of the parts will tolerate a lot of tightening. It's brass, it bends, breaks and strips out easily. Be gentle.

To load your lamp you simply fill the bottom chamber about half way with carbide crystals. You can use powder, I just prefer the crystals. Get it online or at specialty shops. I've heard of florists using it to kill mice. No clue about the accuracy of that potential urban legend.

Overfilling your lamp can do a couple things, it can cause damaging pressure to build up and crack the carbide chamber and it makes for a lot of carbide residue, caustic lime, to clean up.

You can carry a loaded lamp safely if it's dry. That means both chambers. No water up top and a dry carbide chamber. In theory you could just keep your valve closed but that's putting a lot of faith in your little lamp.

Note that ad hoc repairs can be OK if they are solid and safe. The reflector on one of the the lamps I worked on for this Instructable was getting pretty loose and the wing nut didn't have the range to tighten it. I simply added a washer under the wing nut. Not going to burn or do anything funky. Just hold things in place a little better.

Step 10: Light It Up!

Once you've reassembled your lamp and loaded it with carbide and water you can give it a go. ...or realize you are out of carbide and go order some. 

After a couple weeks when your carbide arrives, remove the bottom of the lamp and fill it about half way with carbide. You can use less if you only want to light it up for a little bit. If you are going to rely on it for light you should probably just load it up and not try to guess and then have to refill it in the dark or while fumbling with a secondary light source.( Responsible and sane cavers carry three or more) 

Once you have the carbide crystals in the lamp just screw it back together and add water to the top chamber. I always start with the lever in the closed position and open it slowly. You'll here a kind of hissing noise when the water gets to the crystals and the lamp will start to feel warm. You'll also be able to feel a gentle stream of acetylene coming from the burner tip. You may also notice a less than pleasant smell. The smell goes away once you light the lamp. 

To light it you can spin the striker wheel and the sparks will most likely do the job or you can use a lighter, matches or another already lit carbide lamp.

This particular rebuild was indeed a success.  

Step 11: Resources

If you are looking for parts rather than wanting to make or repair your own you can find quite a few things at Inner Mountain. They carry Minex and Premier lamp parts. 

Bob and Bob is another caving supplier that carries a lot of carbide lamp parts. 

Most of the parts that are prone to break can be gotten from one of those two places. 

You can pick up rubber O ring gaskets at or most any plumbing supply or hardware store. I got mine from Ace so I'm mentioning it here. 

Also remember that you can have a supply of felt gaskets made in a variety of colors through 

You can buy carbide on eBay and from various chemical suppliers as well as the two caving outfitters above or you can get it from Ray-Vin. Ray-Vin also sells a great little product used called the Super Smoker. It's a device sometimes refereed to as a carbide candle. They are used to blacken rifle sites. At $39.95 they are essentially a fully modern high quality carbide lamp without a reflector. I'd love to see one modified for use as a lamp! My guess is that you can also adapt a few of the Super Smoker parts for use in carbide lamps as well. The sparker assemblies are similar and at $5 it's probably worth experimenting with a "fire head" as a replacement burner tip. 

This PDF by Tom Moss  is a little out of date but is dead on in nearly every way. It's a must read for any carbide lamp owner or anyone who would like to be.