Aiptasia/Mojano Burner

[paul b]

Here are the ends of the completed Zappers.

[www.fishnreef.com]

This definitely looks like a fun project to build... I've been ruminating...and now to make the time :-)

[paul b]

I took a video of the thing working. The mojano becomes a little ball of slime that disappears in an hour or so.

 

[paul b]

[lanman]

Okay... yours puts out at least twice the bubbles that mine does. Any hints, tips?? What might cause less bubbles?? I am using a piece of graphite from a carpenter's pencil as the other electrode.

 

Thanks,

bob

[paul b]

I am using 12 volts DC and 500 miliamps. The needle is the negative electrode.

I don't know why it is not working as well. I am also using graphite. How much graphite do you have exposed?

[paul b]

Someone on another forum posted that on the model he was building he had to replace the graphite electrode in a few minutes so I did a test. I ran these two electrodes in salt water continousely for one hour. As you can see by the picture, there is no decay on either electrode. The graphite is slightly discolored because it is still wet.

 

[flowerseller]

 

Looks like after some extended use, my needle probe must have become brittle and broken up some or disintegrated some and is now smaller.

I can tell that some of my graphite, albeit very small amounts, has worn away. It's the needle I'm dissapointed about having to replace soon.

 

 

[lanman]

I am using 12 volts DC and 500 miliamps. The needle is the negative electrode.

I don't know why it is not working as well. I am also using graphite. How much graphite do you have exposed?

 

I am 14vdc 360ma - I have 1/2" x 1" of graphite exposed.

 

bob

[paul b]

It's the needle I'm dissapointed about having to replace soon.

Is it a regular sewing needle or a stainless steel wire?

 

I am 14vdc 360ma - I have 1/2" x 1" of graphite exposed.

 

That should be fine. I can't explain the problem

[Origami]

Someone on another forum posted that on the model he was building he had to replace the graphite electrode in a few minutes so I did a test. I ran these two electrodes in salt water continousely for one hour. As you can see by the picture, there is no decay on either electrode. The graphite is slightly discolored because it is still wet.

 

 

Paul, what polarity is on your carbon electrode and what's on your stainless electrode?

 

Chip, same question for you. You, too, Bob.

 

Also, Bob, can you get a voltage reading between your two electrodes (out of water) using a multimeter?

[Origami]

What might cause less bubbles??

 

Less current flowing would cause fewer bubbles.

[Origami]

It doesn't work worth a darn on those things. They LOOK horrible - and two days later, they are growing again.

 

Bob, I've killed of Outlaw's Palys by injecting them one by one with undiluted muriatic acid (just a drop in each and only a few - up to 10 - at a time). Coincidentally, when you do this, bubbles rise up out of the paly.

[paul b]

Tom the needle is negative and the graphite is positive. If you reverse the polarity, the stainless steel corrodes almost instantly.

Mine use 500 MA DC. 12V.

 

Tom, would you like to try one, I have an older model that I lend out.

Paul

Edited May 20, 2010 by paul b

[Origami]

Tom the needle is negative and the graphite is positive. If you reverse the polarity, the stainless steel corrodes almost instantly.

Mine use 500 MA DC. 12V.

 

Tom, would you like to try one, I have an older model that I lend out.

 

That makes good sense. From my earlier post:

http://www.wamas.org/forums/topic/35756-aiptasiamojano-burner/page__view__findpost__p__308865

 

Which said, "Hydrogen will form at the negative (cathode) end (which supplies electrons) and chlorine gas at the positive (anode) end (which takes electrons away).

 

"I'm guessing it's the anode (positive end) that's breaking down. If so, you're most likely releasing iron and chromium into the water since you're using stainless steel needles for probes. (That's what would happen with copper probes - the anode would disintegrate while the cathode would accumulate.)"

 

Thus, if you (as you mentioned) made the stainless steel probe positive (that is, made it the anode), it would (as you've observed), disintegrate. What's actually happening is that metal ions would be released into the water. Therefore, to keep the metal probe from disintegrating, it's important to make it the NEGATIVE probe. This is very important. As is the need to ensure that the positive probe is not metallic (and to ensure that any metallic connections at the positive probe are not exposed to the water).

 

The gas coming off of the (positive) stainless steel probe in your setup is hydrogen gas. You may see chlorine bubbles at the carbon probe but these will quickly be absorbed by the relatively high pH salt water.

[paul b]

Tom, I ran those probes for an hour in about a gallon of salt water as a test and it became a gallon of Clorox. At least it smelled exactly like it.

You are correct that if you reverse the electrodes the stainless steel will disintegrate in a minute. The way I am using it with the stainless steel and graphite seems to not have any corroding problems. I don't have any wire exposed to the water for obvious reasons of water quality but also because the copper would disintegrate very quickly.

Luckily the only thing that disintegrates is the mojano and that happens in about 5 seconds.

There is nothing left of them as you can see by my videos above

Edited May 20, 2010 by paul b

[Origami]

Tom, I ran those probes for an hour in about a gallon of salt water as a test and it became a gallon of Clorox. At least it smelled exactly like it.

That's because the chlorine gas that comes off of the carbon probe very quickly goes back into solution as hypochlorite (O-Cl) in the high pH environment of the salt water. It smells like bleach because you wind up creating sodium hypochlorite when those hypochlorite ions associate with the sodium ions. Read the label on a bottle of laundry bleach and you'll see that it's sodium hypochlorite!

 

The hydrogen coming off of the stainless probe probably makes it to the surface and escapes.

 

When you reverse the polarity, the metal gives up electrons to the solution, creating ionic metal (copper ions in the case of copper wire; iron and chromium ions in the case of stainless) which readily enters the water, thereby eroding the solid metal electrode.

 

Doing a search on "electrolysis of salt water" provided this link that has a decent explanation:

http://www.thenakedscientists.com/forum/index.php?topic=1298.msg310227;boardseen

 

In any case, when I read that Chip (flowerseller) had trouble with an eroding terminal, it made me think about the importance of polarity in this device.

[lanman]

Bob, I've killed of Outlaw's Palys by injecting them one by one with undiluted muriatic acid (just a drop in each and only a few - up to 10 - at a time). Coincidentally, when you do this, bubbles rise up out of the paly.

 

Yet another good reason to stop at a drugstore for needles. Despite the funny looks I'm sure to get.

 

bob

[flowerseller]

So am I to conclude I might want to reverse the polarity on my probes?

[paul b]

I don't know what the polarity on your probe is but the stainless steel should bubble about twice as much as the graphite.

 

My first prototype used two steel electrodes. They were the same size. look at the lower electrode after about two minutes of use.

 

Edited May 20, 2010 by paul b

[Origami]

So am I to conclude I might want to reverse the polarity on my probes?

Yes, give that a try and see if things turn out differently for you. If you have a multimeter handy, you can simply measure the polarity of the voltage between the two probes and ensure that the metal electrode is the more negative of the two.

[flowerseller]

Mine bubbles like Pauls from the probes.

[paul b]

The needle should bubble about twice as much as the graphite.

If I knew I was going to have to ship so many of these things I would have hired a spokes model. I wonder if there are any Supermodels out of work?

[m3fan8ic]

Paul, where do I stand in the line to get one of this? I desperately need one..:( lol

[paul b]

Paul, where do I stand in the line to get one of this? I desperately need one..:( lol

 

There are only a few ahead of you but I manufactured tools and I can now build them much quicker than originally. Let me know if you want one.