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Registered Member #1938
Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701
Proud Mary wrote ...
Pulse electrolysis. There are dozens and dozens of papers about it.
No time to read . So will stick the electrodes into some electrolyte and see if the amount of gas can be increased in some way at constant temperature and pressure. Honestly, I don't expect pulse electrolysis to provide any noticeable results over CC electrolysys, nor the molecules to follow the magic pulsed/PWM signal like the rats the Pied Piper of Hamelin. I'm just saying this because I've seen lots of youtube users and hobbyists searching for the perpetuum mobile in terms of magic brown gas, HHO, or water cells. These comments do not target you, off course, since you are a very knowledgeable person in many technical fields.
Tonskulus wrote ...
I made similar metal sheet cutter using welder transformer, rectifier, cap bank and heavy choke and carbon electrode. For thin metals, I use just scissors as it is much faster way :) Nice project anyway!
Thanks. You can't do spot welding with the setup you're describing. You can , however, achieve it easily with this setup.
BTW, I tested carbon electrodes and got some very poor results when compared to cooper. They seem to limit the discharge, and at the power levels I'm currently using there is no place for yet another limitation. What I'm saying is I need more power in this system, and lower resistances. So next time I'm working on it I'll make sure to use several litz wires in parallel in the power circuit.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
radhoo wrote ...
Proud Mary wrote ...
Pulse electrolysis. There are dozens and dozens of papers about it.
No time to read . So will stick the electrodes into some electrolyte and see if the amount of gas can be increased in some way at constant temperature and pressure. Honestly, I don't expect pulse electrolysis to provide any noticeable results over CC electrolysys, nor the molecules to follow the magic pulsed/PWM signal like the rats the Pied Piper of Hamelin. I'm just saying this because I've seen lots of youtube users and hobbyists searching for the perpetuum mobile in terms of magic brown gas, HHO, or water cells. These comments do not target you, off course, since you are a very knowledgeable person in many technical fields.
I wasn't thinking of the new alchemy when I posted my suggestion - but more of established industrial processes like electroplating and electropolishing, where pulsed current is often used.
Registered Member #3637
Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068
What about tungsten plated copper?
I think the real reason why graphite and possibly tungsten limit the discharge so much is for the plain reason of just resistance...so if you use tungsten plated copper, you effectively get the conductivity of copper with the durability of tungsten.
Registered Member #1938
Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701
Proud Mary wrote ... more of established industrial processes like electroplating and electropolishing, where pulsed current is often used.
I don't know much about those, but I will try to experiment with this device as much as possible.
Inducktion wrote ...
I think the real reason why graphite and possibly tungsten limit the discharge so much is for the plain reason of just resistance...so if you use tungsten plated copper, you effectively get the conductivity of copper with the durability of tungsten.
A friend will be mailing me some neat tungsten blocks 3x5x30mm so we will find out.
TwirlyWhirly555 wrote ...
Great Build :) , Do you recon a 1F 25 Volt capaitor will be ok , i have one floating about i think it has pritty low ESR .
Thanks, 1F 25V should be fine for this purpose. I am also considering Supercapacitors, but from what I understand car audio caps are the same.
Registered Member #1223
Joined: Thu Jan 10 2008, 04:32PM
Location:
Posts: 133
I'm not sure if carbon electrode works at all with this kind of pulsed system. Continuous arc is required I think.. this ensures that carbon never touches the actual material to be cutted. There is always gap / arc beetween them. Using smooth high current DC can produce very high temperature arc.
Registered Member #1938
Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701
Tonskulus wrote ...
I'm not sure if carbon electrode works at all with this kind of pulsed system. Continuous arc is required I think.. this ensures that carbon never touches the actual material to be cutted. There is always gap / arc beetween them. Using smooth high current DC can produce very high temperature arc.
Indeed carbon doesn't work. The discharges where so limited that they where unable to heat the material, not to mention cutting or soldering. I'll be testing tungsten carbide during this week and post results.
Registered Member #1938
Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701
The project is ready!
update 2: February 9th, 2012 I need to decide what type of LCD to use: the 2 lines HD44780 LCD, or the bigger one, with 4 lines. The code I wrote works with both. The larger one would have the advantage of allowing more text to be displayed. The smaller one is on the other hand more compact, better suited for my small case.
Update 3: February 22nd, 2012 I purchased a suitable capacitor. Finally! It's a Pyramid Royal Blue, CAP160DBL 1.6V . The first thing I did was to dismantle the useless electronic part and the display. By doing so, the new size fits perfectly to my project box. For those complaining that this type of capacitor, when used for car audio systems, doesn't switch off and depletes the car battery, simply unscrew the connectors to take off the display part. You won't be needing that anyway:
Update 4: March 1st, 2012 The project box, in the final shape is ready. I had to cut some more wood, but that's an easy task if using the proper tools (I got a nice pendular saw). For a quick test I tried using a halogen 12V electronic transformer. That was a waste of time, as those things are unstable, and not working properly (they are barely oscillating): The box exposes the heatsink, a standard PC power connector, and a fuse holder. The big capacitor is mounted on the top, as it looks nice and is too big to fit inside anyway.
Update 5: March 3rd, 2012 I resisted the temptation to throw that halogen electronic transformer to the trash. It was such a waste of time! Instead I found a charger, from an old laptop. It is a 90W, 19.5V SMPS supply, with the perfect size for my box. Initial tests shown it is capable of charging the capacitor (with a short initial blackout), and even hold the intense Arc cutting mode power consumption. As this was another Chinese cheapo, some optional components such as filter, capacitors, etc where missing from the PCB, and I added those first. Next I did a heatsink upgrade, to make sure it will run continuously, for as long as I need to use the tool: So far this proved to be an excellent choice! My device can now be powered from a 110V-220V outlet. For the control panel, I needed a few potentiometers and some push buttons. I used a few NOS Russian 47K pots, I got from Gintaras Ebay show, KWTUBES. You can get some high quality components there at fair prices. Some pins are used to interface with the floating cables coming from the PCB modules. By doing so, I can easily dismantle and re-mantle everything together.
Here's how the setup looks like now:
For the working electrodes I ended up using copper. But not just copper, also a new innovative design: the thick wires are connected to the electrodes using a screw, a screw nut and a washer. The electrode itself is a 10cm metal hollow tube. Inside, copper wire can be inserted, and while working, it can be pulled outside when needed. Exactly like a rotring pencil : the cooper electrodes is eaten while in use, but conveniently can be extracted from within the electrode, or replaced.
Registered Member #1938
Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701
I recently received a few Tungsten Carbide rods. This excellent material has a high melting point (2,870 °C), it is extremely hard (8.5–9.0 Mohs scale) with low electrical resistivity (~2×10−7 Ohm·m) making it an good electrode material for the Capacitor Welder. I hope to see it solves the molten sticky metal issue I had with copper electrodes. Results show excellent performance:
Here are the electrodes showing minor signs of use after this cutting session:
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Capacitor Discharge Microspot Welder / Cutter
. So will stick the electrodes into some electrolyte and see if the amount of gas can be increased in some way at constant temperature and pressure. Honestly, I don't expect pulse electrolysis to provide any noticeable results over CC electrolysys, nor the molecules to follow the magic pulsed/PWM signal like the rats the Pied Piper of Hamelin. I'm just saying this because I've seen lots of youtube users and hobbyists searching for the perpetuum mobile in terms of magic brown gas, HHO, or water cells. These comments do not target you, off course, since you are a very knowledgeable person in many technical fields.
when I posted my suggestion - but more of established industrial processes like electroplating and electropolishing, where pulsed current is often used.
