Homemade Generators

[cavemanjonny]

Jonny... What is your motivation to make your own generator? If it's the love of tinkering and building things yourself, then have at it. If it's due to frustration with current generators not working correctly, I may be able to shed some light on the subject for you.

It's a little of both, really. My generator mysteriously disappeared, so I figured I'd try to have some fun, maybe save some money, and maybe get a better generator by building it myself. It looks like all 3 might be possible!

Since shedding light is the ultimate goal of this project, I'd love to hear your thoughts on the subject.

[emesine]

One thought-

There is really no limit to how big you could scale this lamp. If you build the canisters out of 3-4 inch PVC pipe and used larger lines for the water and acetylene tubes you could make a really, really bright lamp. IT might be fun for video or photos in some of the large rooms in TAG. Just for fun...

Andrew DuBois
39966

[Adam Craig]

I toyed with this idea of making my own generator after destroying two Petzl generators. Once I learned how to use the Petzl, it has been operating flawlessly and very nicely. I highly doubt you could build a better generator for under the $75 cost of a new Ariane. It's very possible to build a functional generator for under that price, but longevity and robustness would be the big hurdle. Keep in mind that spent carbide is highly toxic to fish, so a catastrpohic generator failure in a cave could have serious environmental impacts, let alone personal injury.

Things to keep in mind. First, the size of the generator has ZERO impact on how bright the lamp is. That's determined by flame shape (a property that's dependant on the tip nozzle design) and the rate at which you produce and burn gas. Secondly, brass works fine with acetylene, but copper is the big "NO-NO". Unalloyed copper in contact with acetylene produces copper acetylide which may explode. Third, under no cirumstances should acetylene be allowed to build up pressure in excess of 15psi. At that point, it can spontaneously explode = BAD, BAD, BAD

My suggestion is to buy an Ariane, learn how to properly operate it, and you'll be good to go. It's probably the easiest, safest, and most robust generator that's currently available.

[Martin Sluka]

Keep in mind that spent carbide is highly toxic to fish, so a catastrpohic generator failure in a cave could have serious environmental impacts, let alone personal injury.

As far as the spent carbide is calcium carbonate as the limestone or flowstone is.

The acetylene itself is dangerous - it destroys human teeth, you may be poisoned by it theoretically, but I never heard about it in real life.

There are many other potentially very dangerous things in our real life and we are still here.

Ariane - thanks, NO!

Martin

[Martin Sluka]

"advanced" model of spray tis acetylene generator :)

Made from silon, silicone tubes, the pump used was windscreen washer manual pump from old models of Fiat.

Just for fun

m.

[Adam Craig]

As far as the spent carbide is calcium carbonate as the limestone or flowstone is.

Spent carbide is NOT calcium carbonate, i.e. limestone. The reaction is CaC2 + 2 H2O → C2H2 + Ca(OH)2, which reads calcium carbide + water produces acetylene plus calcium hydroxide. Calcium hydroxide is listed as "Harmful to aquatic life in very low concentrations". http://www.chrismanual.com/C/CAH.pdf

My point was that a homemade generator MAY be more susceptable to damage or catastrohic failure than a production version would be.

[emesine]

Hmmmm.... Copper acetylide explodes, eh? Perhaps this is a thread for the cave digging forum??

I have used the Ladya design for years in very tough caving environments. When I retired the lamp the aluminum canisters were bent and scratched. I have overpressurized the lamp (probably above 15 psi) enough to blow the stoppers out. i have sat on it, I have dropped it, I have thrown it down pits. I have never dropped any carbide, spent or otherwise, in the cave. I understand your concern on theoretical hazards, but it is a proven safe design.

I agree with sluka- no thanks on the Airane. I spent too much time banging it on a rock to get it to work right.

Andrew DuBois
39966

[Martin Sluka]

Spent carbide is NOT calcium carbonate, i.e. limestone. The reaction is CaC2 + 2 H2O → C2H2 + Ca(OH)2,

You are THEORETICALLY absolutely right. BUT if the Ca(OH)2 is so dangerous it is quite funny I have all my fingers till now. There is really BIG difference between Ca(OH)2 as the product of lime slaking and product of acetylene generation. I saw people from Asia selling at home made slack lime by hands and they don't use any king of glove. They had all 10 fingers too. Ca(OH)2 is dangerous if contact eyes but a small piece of carbide is much more dangerous.

Practically the spent carbide - Ca(OH)2 - quite fast reacts with CO2 from cave air or cave water and creates CaCO3 (Ca(OH)2 + CO2 = CaCO3 + H2O), what is the same material as base of limestone or flowstone.

[ek]

Practically the spent carbide - Ca(OH)2 - quite fast reacts with CO2 from cave air or cave water and creates CaCO3 (Ca(OH)2 + CO2 = CaCO3 + H2O), what is the same material as base of limestone or flowstone.

Hmm...where can I read more about this secondary reaction you speak of?

[Martin Sluka]

Practically the spent carbide - Ca(OH)2 - quite fast reacts with CO2 from cave air or cave water and creates CaCO3 (Ca(OH)2 + CO2 = CaCO3 + H2O), what is the same material as base of limestone or flowstone.

Hmm...where can I read more about this secondary reaction you speak of?

:) I'm sorry, but on this base all the human constructions using masonry are based. Several thousands years I believe.

1. Our ancestors made burnt lime. They just roasted small pieces of limestone in fire. They used broken karrens often because it was most simple way haw to receive small pieces of limestone. It is the reason you may not find "karren fields", typical for karst plateaus, at many places with long human history.
2. They leaved the burnt lime reacts with water to prepare slack lime
3. They used slack lime to prepare masonry
4. The calcium hydroxide from masonry reacted with carbon dioxide from air (they often used the fire which produce CO2 to accelerate this) and created hard material which glues bricks or stones together up to the present days.

The same procedure is using on today's constructions.

Check:

http://en.wikipedia.org/wiki/Calcium_hydroxide
http://en.wikipedia.org/wiki/Mortar_%28masonry%29

The product of reaction of carbide with water is identical with product of reaction in step 2. And step 4 is common for both as burnt lime as carbide.

Martin

[halo]

This may be true, but even if the reaction happens "very fast," there are many other side reactions happening at the same time. Some of the calcium hydroxide will react in adverse ways in the cave. In the time it takes to become harmless, the damage is done. The reaction that precipitates the calcium carbonate also requires pure carbon dioxide to be pumped through the aqueous solution. This is easy to obtain in the laboratory, but impossible in a cave. There simply isn't enough surface area for the reaction to happen quickly enough.

I've had my hands in this crap every time I clean out my generator. It doesn't cause any permanent damage, but I can see the holes it starts to eat in the skin as the dry and dead skin flakes off over the next week, That's with limited exposure and a resilience that a cave creature doesn't have. If they are in a puddle where you spill some, they are dead.

My point is that calcium hydroxide does not belong in a cave. I'm all about people building their own equipment, and carbide is predictable enough to build your generator as long as you research it well. However, bear in mind that a catastrophic failure of the system (or any introduction of carbide waste into the cave system) will, while being not so harmful to you, will wreak havoc on a cave's ecosystem for a long time.