What causes this?

Indeed. Even if you used the Advanced Polish toilet paper, where you take a square of TP and fold it into quarters, then tear off the tip where the 4 squares meet. The piece is unfolded and then placed over your bird finger to the second knuckle, used for its purpose, folded over the finger and pulled off to clean off the finger, and the small piece used to clean your fingernail.

(This is a real hoot to show to people.)

-- Inside every older person is a younger person wondering WTF happened.

Reply to
Larry Jaques
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On Mon, 31 Oct 2011 21:03:16 -0700, Larry Jaques

[...]

Aren't we fortunate this place isn't moderated!

But back to the original problem - I think I found the solution. The bubbles *are* a problem and if one keeps the electrodes 1" apart and vertical the etch is pit-free.

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Michael Koblic, Campbell River, BC

Reply to
mkoblic

You betcha!

Cool! Now to figure out why 1 inch is the key to pitless etching of that material with that solution and power supply. Maybe a perfect multiple of the bubble width?

-- When you are kind to someone in trouble, you hope they'll remember and be kind to someone else. And it'll become like a wildfire. -- Whoopi Goldberg

Reply to
Larry Jaques

Nah, the bubbles just don't go near the anode. I suspect the poor result on Plate 5 was because the precipitate was holding the bubbles in the electrolyte and they got closer to the anode. Although plate 4 was closer to the cathode the electrolyte was clear and the bubbles were free to escape.

Tomorrow I am going to look at a container big enough and narrow enough to do some of the bigger pieces side-by-side so there is enough space between the electrodes yet I do not have to use a gallon of electrolyte every time.

Anyway, I moved onto brass today which I thought I had pretty much worked out. I did two small plates and observed some really weird behavior. OTOH I do not care as long as the result is OK.

Michael Koblic, Campbell River, BC

Reply to
mkoblic

I think I was referring to any electrical characteristics of the electrolyte may have, wondering if it equated to bubble (or potential bubble) size. I know that there are shadings in solution, so parts not directly in line will have different etch characteristics. Jeeeze, I haven't done any etching in a couple dozen years, and even then, it was plating.

What precipitate? The etched material?

Is this entirely sacrificial, or can you reuse electrolyte?

Got eight-by-ten colour glossy photographs with circles and arrows and a paragraph on the back of each one explaining what each one was to be used as evidence against us?

-- Knowledge speaks, but wisdom listens. -- Jimi Hendrix

Reply to
Larry Jaques
[...]

From my careful scientific observation: Mo' current, mo' bubbles.

Ferric Hydroxide. Some ferrous too I think. When the acetate is used up the iron begins to precipitate. If you omit the vinegar it happens right at the start.

CuSO4 I re-use all the time. Just top up the wastage and evaporation. Salt and vinegar needs to be fresh for the reasons above.

You lost me there. Something to do with Mchael Jackson perhaps?

Michael Koblic, Campbell River, BC

Reply to
mkoblic

LOL, No. Arlo Guthry - from Alice's Resturant

Reply to
Richard

A truly "Duh!" moment, was it?

OK.

Cool. That's an inexpensive bath.

Those pretty blue crystals are good for poison oak/ivy, too. Make a solution and pad it on the affected area. It'll make your skin crawl for a few minutes but it removes the oil, the itch, and the spread. I haven't noted any toxic feeling afterward, but it's a 1-time bath.

Newp, I don't have anything to do with the Jacksons, ever.

We must have hit the cultural divide between our countries. Arlo Guthrie's song "Alice's Restaurant" is a cult classic here in the States. Listen to it and weep:

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Another cultured fave is "The Motorcycle Song"
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"I don't want a pickle. Just wanna ride on my motorsickle."

OBTW, this is folk culture, not opera or symphony or sumpin'.

-- The unexamined life is not worth living. --Socrates

Reply to
Larry Jaques

Ah, but I wish it was all that simple. I just rigged up my new set-up:

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(and the next two pics)

The results are beautiful, but then I could do the small pieces with negative etching quite well before. The thing that was interesting was the unidirectional movement of the hydrogen bubbles *away* from the anode.

The proof of the pudding will happen in a day or so when I shall repeat the etch that sparked the OP.

[...]

Here they use them to kill roots in septic tanks. Actually I am using a commercial solution sold by jewelers' supply company for copper plating. I do have a bunch of CuSO4 crystals which I will go to next when I run out of the current solution.

I seem to remember a movie of similar name. About 1970? I was never into the hippie thing.

Your culture. I shall stick to "Does your chewing gum lose its flavor on the bedpost overnight?", "Calendar song" and other such masterpieces.

Michael Koblic, Campbell River, BC

Reply to
mkoblic

It is a popular culture reference. :-)

You never heard the full 18 minute 34 second run of Alice's Restaurant -- a cant-fable (talking and singing mixed) by Arlo Guthrie back in the 1960s I believe.

This will tell you about it:

Reply to
DoN. Nichols

Y'know, that looks like a januwine termite barf inlaid Harbor Freight workmutt clone that your etch tank is resting upon. I sold mine in my garage sale a few months ago. Nice power supply, sir.

Yeah, that's fun. Now reverse the polarity and see what happens!

G'luck!

Doesn't it kill the beneficial bacteria, too?

Yes, 1969, starring Arlo Guthrie his own self.

Um, OK.

-- The unexamined life is not worth living. --Socrates

Reply to
Larry Jaques

The movie was based on the events in the song.

Enjoy, DoN.

Reply to
DoN. Nichols
[...]
1) Close - Crappy Tire. With a bit hacked off during the Heroic Fence-building of 2011. 2) It *is* nice. $6 in a garage sale. It keeps constant current up to 3A. It is particularly useful when doing brass as the voltage seems to dance around a lot doing that.

Some other time.

[...]

Who knows? Who cares? The Global Warming will kill us all anyway!

Michael Koblic, Campbell River, BC

Reply to
mkoblic

Gunner Asch on Sat, 05 Nov 2011 11:30:56 -0700 typed in rec.crafts.metalworking the following:

Reply to
pyotr filipivich

Gunner Asch on Sat, 05 Nov 2011 00:02:23 -0700 typed in rec.crafts.metalworking the following:

They even made a movie of it.

"It might be a movement!"

Reply to
pyotr filipivich

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