Hi Friends,
A while back I posted a question about a Friul guide and got lots of useful links and advice. Thanks again!

One poster wrote that the white metal was not steel, but lead and tin. Other posts there mentioned vinegar to clean off the release agents.

Trying to find blackening agent in Australia has been a failure. It's made of nasty stuff, apparently. I couldn't find it wherever I looked. And getting it shipped from overseas looked like a non-starter.

The lead-blacken connection has been lurking in my brain for a week. Only today did I realize why...

I am a relative noob at soldering. I've used it on a few brass pieces on models and after much cursing, praying, and frustration got pieces to bond together for me.

Anyway, part of the soldering process calls for you to soak your work in a solution called 'pickle' after the pieces have bonded. Pickle neutralizes the acids in the flux which is part of the soldering process. Pickle in itself is acidic.

When I would pull my soldered pieces of brass from the pickle, any area that got solder on it was blackened.

Solder is primarily lead. So finally the connection jumped into the front of my mind. Lead + pickle = Blackened

Here it is in photo process:


1: The new, unwashed, fresh-from-the-bag piece of Friul from my late Tiger 1 set.

2. After soaking in the pickle, here is the smoother, inner part of the track.

3. Here is the part of the track that has all of the detail and places to trap air bubbles. After an hour of soaking, I lifted the pieces from the pickle, and rinsed it seeing that there were 4 large pockets of air that had left the track untouched by the pickle. After another 40 minutes of soaking, the piece looked like this.

4. The same piece after a few strokes with a wire brush and sand paper. I did a crappy job, because my wire brush is too huge. A smaller brass brush would have done better.

So, here is the ingredient list:

1. A Crock pot or other way to keep your salt and vinegar pickle hot for a couple-few hours. Heat is the key. Heat activates the pickle. Pickle will eat metal pans. So, you need a ceramic pot of some kind.

2. White vinegar.

3. Salt.
Your salt and and vinegar ratio should be one cup of salt to one gallon of vinegar.

That is all you need for your pickle.

4. Baking soda and water. Pickle is acidic. Baking soda is a base. One gallon of water to one cup of baking soda.

The process is simple:

Put your Fruils in your crock pot with the heated pickle. Let them soak until they are at your desired blackness. Lift them occasionally to check for air bubbles. Eradicate the bubbles with a fine bristled brush.

After you've got them as black as you want them, put them in the water and baking soda mixture to soak for a couple of hours.

Lastly, rinse with clean water and leave to dry.

Except for the crock pot, everything else is dirt-cheap and easy to find. The pickle will last for some time, but will eat away at anything metal. The vapors will even attack the metal edge rim of your crock pot lid. To neutralize the pickle you can just dump in some baking soda.

I hope somebody finds this helpful. This was an experiment today to see if I could make it happen. When I get to the place in my build where I am ready to assemble my Friuls, I'll try this method to an entire set. If anyone has thoughts on bettering the process, please feel free to say something.


Thanks for looking,

Gary

mmm salt and vinegar. I'm hungry for fish and chips now!

Sounds like a great tip, but I have one question. Can't the tracks just be painted? Is there a clear advantage to blackening?

Yes, they can be painted. As with any model, it depends on the finish you want. Painting tracks with deep waffle-like squares takes some time and effort, and you have to hit every angle to get every surface, nook and cranny.

Tiger tracks have lots of nooks and crannies.

Thanks for the information, Gary. Never thought about adding salt to the mix.




So is Vegemite; but, it's still sold without a hazmat label.

I grew up in the States, never tasted vegemite until I was 35...
I've tasted some bad things, but vegemite ranks at the top of the list of things I never want to touch my tongue ever again.

When soaking Friul (or similar) tracks in any blackening agent, you have to agitate it vigorously periodically to dislodge air bubbles attached to the tracks. The air bubbles prevent blackening of that spot.

Good point!

Guys;

Use a stainless-steel pan and you'll be A-OK with the "pickle" - stainless steel won't react with either the vinegar or the salt even with prolonged cooking (I make pickles and such... this is what I use for that task).

Just buy a cheap 1-quart stainless pan with a stainless lid. A great place to get this would be your favorite GoodWill or Salvation Army junk store.

Save your next plastic orange-juice bottle and plastic cap - or even a 1-liter plastic soda bottle and cap - to use as your perfect non-corroding "pickle" storage container.

Cheers!

Bob

Hi Everyone,
I have to add an apology. It turns out that my original conclusions were wrong. The bleach and saltwater pickle doesn't blacken the tracks. I made a new pickle, since much of the other had evaporated away and started fresh. I dropped my Friuls in, and nothing much happened. It dawned on me that it wasn't the pickle that caused the tracks to blacken. It is the reaction between the pickle, the lead in the tracks, and the copper sulfate in the pickle. The copper sulfate plates the lead! So, I had to introduce copper sulfate into my new, clean pickle.

Copper sulfate is what turns the salt and vinegar in the bottle green. It's easy to make, however. All you need is fire (a handheld torch is easy to acquire), and some brass or other alloy containing copper (copper pipe for example). For me, I used some brass sheet from another project. You simply heat the copper until it turns color (called firestain), then drop it in the pickle. The acid pickle will eat away the firestain leaving the copper clean and pinkish. Lift out your copper once it's clean, and burn it again. I had four sheets like the one in the picture, and I burnt/cleaned them four times. It left a nasty sludge at the bottom of the pickle which I filtered out after blackening the tracks and letting it cool.


That is one track blackened and scraped, and one just blackened.

And here are the tracks mounted on the Tiger. After brushing off the raised portions with a wire brush, I sealed them with Future.


Again, sorry for passing bum scoop. Hopefully someone will find this useful after all.

Gary