Q: I have difficulty operating my Minex. Do you have any advice?
A: Yes. I have received a number of e-mails from Minex users about the lamp, and I myself have gone caving with them before. The lamp has some design errors that can often complicate use. The later model of the Minex (the 115C) is a functional lamp, but it has more quirks and requires more attention than other models. I have categorized the common problems:
Jumpy flame on startup
This may be a fact of life while using the Minex. The first five minutes of operation are marked by considerable acetylene being shunted up through the water chamber, a flame that blows itself out, and a rapidly diminishing flame. The valve stem does not always quite touch the carbide when the lamp is just getting started. To help reduce the wait for pressure to even out, you may slightly overfill the lamp bottom. Make sure the carbide level is just slightly over the round divots in the lamp bottom, and then start a drip rate of about one drop per second. As the carbide expands, the above problems will decrease. This will eventually lead to the calcium hydroxide becoming packed into the bottom of the lamp, but it you can remove it with some work using a blunt instrument.
Jumpy flame after startup
The Minex's water feed is particularly sensitive to jostles and bumps. Agitating the lamp will increase the amount of water being fed to the carbide. Furthermore, because of the Minex's rather unique drip mechanism, acetylene may be regularly shunted up through the water chamber. Keeping a full water chamber may help slightly to reduce the occurrence of bubbling and gurgling. (This will keep a greater amount of water pressure, and it will take slightly more gas pressure to shunt the acetylene.) Whenever the Minex looses acetylene through the water chamber, the gas pressure in the carbide chamber changes, causing a less regular flame. Because of the general nature of the drip mechanism, a jumpy flame is a fact of operation, and apart from modifying the lamp, Minex users will have to grow accustomed to this "feature."
Frequently wet felt
This could be easily remedied by tightening the valve stem/felt holder with a pair of pliers. If the valve stem/felt holder is loose, water will leak into the felt.
Regularly high flame
Again, the Minex has a drip mechanism that is sensitive to jostles, shakes, and bumps. Backing off the water feed may help compensate for this. Some cavers have chosen to intentionally set the drip mechanism low, and let the normal process of walking or crawling shake extra water into the carbide chamber. Should the regular jostles become insufficient, shake your helmet (and thus the lamp) a bit to encourage more water into the carbide chamber.
Rapidly extinguishing flame
As mentioned above, the Minex's drip mechanism is particularly sensitive. Be careful to keep the lamp upright during operation.
Q: Is the Mike Lite a quality lamp?
A: Before using mine underground, I subjected it to grueling tests in attempts to manufacture failures. Most attempts to manufacture complications have failed. The lamp appears to be a very solid lamp, and I have yet to hear any serious complaint from anyone who owns one. It runs smoothly and efficiently. The Mike Lite is a product of years of research and field-testing. They have proven to be sufficiently heat resistant, durable, and reliable.
However, the Mike Lite does have its own personality, and operating the lamp is slightly different from older brass models. Most notably, the Mike Lite requires less water, just slightly under a drop ever second. This is because the Tivar insulates the carbide chamber resulting in a warmer gas. Warm gas expands and creates adequate pressure while using less water and less carbide. Setting the drip rate too high may temporarily clog the drip mechanism. When starting up the lamp, it is more effective to start the drip rate, attach the lamp bottom, and then wait for the pressure to build up (as opposed to spitting into the lamp bottom, attaching the bottom, and then starting the drip rate). Spitting into the lamp bottom before fastening it to the top may cause a temporary clog in the drip mechanism.
Q: Where can I find soldering materials fit for repairing my carbide lamp?
A: I have seen soldering irons at both hardware stores and at Hobby Lobby. If you go to a hobby store, look in their stained glass section. There they will have lead solder and soldering irons. Silver solder can be found at Wal-Mart or other such stores. Remember; never use the solder from electronics stores such as Radio Shack.
Q: Do you make the Mike Lite?
A: Sorry to disappoint you. I don't. I own a Mike Lite, but that is about as close at is gets.
Q:Do you know where I can buy a Mike Lite?
A: Yes. The Mike Lite was out of production for several months, but they are now back and easily available from Inner Mountain Outfitters.
Q: Will you sell me a lamp?
A: No. I'm not in the business of buying and selling lamps. There is one Autolite that I would be willing to sell, but you don't want it for the same reason that I don't.
Q: Will you sell me some repair parts?
A: Sorry, but no. Since I'm not running a business, I only have enough repair parts for the lamps that I use.
Q: What kind of shelf-life does calcium carbide have?
A: How long carbide will last in storage is dependant on what kind of container you keep it in and where you keep it. Calcium carbide reacts to moisture and that includes moisture in the air. If you live in a humid environment and keep your carbide in a can or tin that allows the air to get in, then it will begin to degrade. If you vacuum seal your carbide, you can expect it to last virtually forever.
Q: If I can't find the information I'm looking for on this page, where can I go?
A: Feel free to e-mail me at firstname.lastname@example.org, but if I don't know, then try the Caplamps Yahoo Group. There are a lot of really great cavers that subscribe, and they can probably help you.