Zen » Experiments

Poor man’s chrome plating

Zen — Sun, 31 May 2009 20:00:06 +0000

Some time ago I got interested in the basics of amateur electroplating because I wanted to nickel-plate the tip of a soldering iron.

An excellent Wikipedia article gives more than enough information for beginners, but it was really the YouTube videos that got me decided to try this at home.

In theory, by hooking up the metal we wish to transfer on the anode(positive), and the other piece of metal at the cathode(negative electrode) and we place the whole frankenthing into a certain conductive solution, we get electroplating.

As with every craft, there’s more to it than just that. A LOT more! But yesterday I celebrated a first successful plating of a copper bar into something resembling stainless steel. It’s definitely not “chroming” because obviously the result is not pure chrome…

I thought of doing a tutorial on how I did this but it’s too dangerous and I’m not an expert, obviously, to be able to provide you with all the caveats for a 100% safe experiment. So I couldn’t recommend anyone messing around with electricity, acids and possibly toxic fumes without putting you at risk. I decided to just share my photos so you see that with a very simple setup you can achieve some interesting results.

If you’re interested in the process, YouTube has plenty of professionals demonstrating the process. Don’t try this if you’re not used to working with electricity and chemicals. Some dangerous fumes are produced during SOME processes(not this one I used) so beware of the nickel and acids recommended on some YouTube videos.

Initial copper bar, dipped in vinegar and salt to remove oily finger stains, then rubbed with a soft steel wool to remove dirt.

I needed some chrome, so I used this handle I found lying around.

I found an old refrigerator drawer and mixed some home ingredients in, among which are vinegar, lemons and salt. If you go for stronger, industrial-strength acids, beware of the fumes that are produced. You should also take great care in disposing of the experiment chemicals later or store them in a safe location.

The cathode, or the metal receiving the plating, seems to boil during the process. If you’re doing this right, it should not be very hot at all, just a bit warm. It is actually liberating hydrogen and gases as a result of the hydro-thingy-whatever reaction. I wasn’t sure exactly what was coming out, so I had a fan ventilating the workshop at all times. I wouldn’t do this in a basement or closed garage.

After we remove the bar from the acid, we immediately wash it in running water and then polish it slightly with a soft steel wool.

Many previous attempts were less than satisfactory.

I think some of the iron from exposed parts of the handle got transferred as well because this looks a lot like a mix of chrome and iron…it is definitely not pure chrome.

This LED works with up to 80 V AC from mains line

Zen — Thu, 21 May 2009 01:42:32 +0000

Here are a few photos so folks can help me understand how this LED works perfectly with more than 80 V AC, in series with a 10k OHM resistor, directly from the mains line.

In this case I’ve tested with 2 10k resistors, dropping the voltage a further ~5 volts.

The resistor gets pretty hot. It stays only warm with 2 of these 1/4 watt 10k resistors in series. The LED stays cold…left it on for over 1 minute, nothing unusual except for the fact the voltage drop on the LED is over 80 V AC RMS.

Solution
What was I doing wrong? Well, it’s a pretty trivial mistake really but I hadn’t seen it. Every half cycle there was little or no voltage drop across the LED, so the multimeter sampled 223 V AC. Then on the conducting half cycle the resistors produced a big voltage drop, and the multimeter sampled that low voltage as well. The result was some sort of average computed by the multimeter. Unable to figure out how that LED withstood 75 V AC I went to Electro Tech Online and asked. Members of the forum were immediately on the case, offering ideas. It didn’t take long before 2 or 3 folks had it solved: place another LED in opposite polarity and the multimeter will display the correct reading. Result? 2 V – which seems like a correct reading. There I go, one more lesson learned.

Mistery device: Can anyone ID/date this motor/generator please?

Zen — Sun, 15 Feb 2009 11:59:51 +0000

This piece was sitting at our shop, dusty and forgotten in a tool closet. It suddenly caught our attention the other day and we decided to clean it up and research about its original function.

We couldn’t find anything about it on the Web, nor the name on the shield or any similar gadgets. Maybe some of you know what it is and can help us date and precisely identify this piece? It is really well built mechanically and quite heavy as you can guess.

We thought it could be part of an old German automobile generator? What application could this have?

It does generate about 12V RMS pulsed DC at about 2500 RPM(driven from a drill attached to the axis) with the coils connected in series and then the coils in parallel with the brush / rotor windings. We tried a few combinations of coil and brush hookups. The coils heat up minimally hooked up to a 12V car battery. The wire in the rotor windings seems to be 1mm in diameter approximately(we did not take it apart).

The nucleus is solid, not laminated. We could not measure the inductance of the coils because our only inductance meter was accidentally inserted into a 220V socket…The nucleus is closed by a magnetically isolating plate made of brass. Every other piece attached to the nucleus is also magnetically isolating, all likely brass.

Face plate(shield) says
CLIMAX
Bachrich & Co
Hamburg Wien

Well, here it is. Any information greatly appreciated!