How do they do this?

Don't use so much heat! You only need to get the copper to a temp of about

400F at the hottest to get a full melting of the solder with some headroom for the melting of it. Gas welding usually gets the surface real hot and tarnishes the copper quickly. Another thing is that there are resistance soldering systems that will help keep the copper from being too hot as the hottest place will be at the joint where the contact is minimal. FWIW, I've done soldering with a hot air gun! It works and doesn't get anything too hot.

-- Why isn't there an Ozone Hole at the NORTH Pole?

On Mon, 7 Mar 2005 17:48:34 -0800, the inscrutable "Lane" spake:

The FLW trellises don't look all that clean, Lane.

think it's hidden in the faraway pictures. The only closeup on the page is of a piece with the green patina. Are you sure they don't solder vs. brazing the joints? (The words "solder" and "braze" are not found on their pages.)

BTW, I love that repoussè work at the bottom of the page.

========================================================== I drank WHAT? +

--Socrates + Web Application Programming

"Lane" wrote in news: snipped-for-privacy@comcast.com:

May be induction heating it. As another poster stated, the temp to join copper is not very high.

(...)

You might post to our buds at sci.engr.joining.welding

--Winston

The brazing I do requires heat around 750 degrees F.

Done, thanks. I should have thought of that. Lane

I use brass but still have the same problems. I have to get my pipes red hot and this in turn causes them to turn a nice blotchy gray/black. The first step is to dip them in a 50/50 solution of muratic acid and water followed by a long water bath. Finally I buff in the classical manner. Comes out great.

LB

When you say dip, what exactly do you do? Would a spray on or brush on approach work? Then rinse with a water spray. My work is too big for a dip into a tank. Lane

Which reminds me, what's the easiest way to remove that black hard gunk left from borax flux? Brass brazing copper or steel here...

Tim

-- "California is the breakfast state: fruits, nuts and flakes." Website:

Boiling water and time.

Harold

Depending on the nature of your project, you might consider using dilute sulfuric acid. It readily dissolves copper oxide but won't touch the copper. You can restore the original copper color, but it may not be shiny. If I'm not mistaken, industry uses a cyanide process, but that is beyond the ability of the home shop, cyanide being nearly impossible to buy, and certainly more hazardous than one should risk at home.

Sulfuric is not a good choice if your joints include brass because the sulfuric will attack zinc, quickly dissolving enough of it away to change the color to a copper color and reducing the brass to something on the order of Swiss cheese. A long enough exposure would permit the brass to disintegrate.

Harold

Do you have to braze? Will silver bearing soft solde work? Will Sil-Phos work? Just how much strength do you need? Maybe you can soft solder a joint and then twist it to see where it fails. Eric

Jewelers that I know always seem to have a dish of Sparex (or Sparex #2) for cleaning things. Try this search and see where it takes you:

+sparex +jewelry

Pete Stanaitis

-------------------

Lane wrote:

I am using Sil-Phos, namely JW Harris brand DynaFlow. I was told that that is brazing. I used soft solder before and had problems with joints failing, I went to Sil-Phos which requires higher heat and a lot of clean up.

You should try lurking on rec.crafts jewelry. You need a pickle solution, which you can brush on immediately after soldering, takes all that horrid stuff right off. Instead of Sparex, which the pros there say is expensive and not very pure, they recommend some form of pool Ph reducer, basically sodium bisulphate, same ingredient as Sparex. Cost is about 8$ for 7 pounds, so is very economical. Make up a saturated solution in hot water, then brush it on the joints. Rinse with cold water. Richard in Los Angeles

Greetings Lane, Unless you're gonna use flux on the outside the parts will need to be cleaned. Sparex was mentioned. That would be Sparex #2 which is sodium bisulphate. Mix the stuff into water. It works better when warmed. Apparently some manufacturers will plate over, rather than remove, the discolered surface. A flux which I like is prips flux. Don't know if it should be capitalized. But it is made like so: RECIPE FROM THE COMPLETE METALSMITH

2 fluid oz borax 2 fluid oz tri-sodium phosphate (TSP) 3 fluid oz boric acid. Boil the above ingredients in 1 quart water. Longer boiling makes it better. The stuff is used by putting it in a spray bottle. Heat the work but not enough to cause discoloration. Spray the flux on the part and it will dry. Do this a few times till an unbroken coat forms. I use a solder from called Tarasil 946. Made by Tara Corp. It's 94% tin and 6% silver. It is the strongest silver bearing soft solder I have found. Proper cleaning and fluxing of joints really cuts down on joint failures. One last thing. Use enough flame to bring the parts up to heat fast. A smaller flame will take a long time to get the parts hot enough and they will be at elevated temps longer than with a larger flame. Within reason of course. Using an oxygen lance will vaporize the work before you get a chance to apply the solder. Eric

Eric Ok, I'll give the Tarasil a try. Thanks Lane

I make up a saturated solution of either sodium bicarbonate or washing soda in hot water and soak the brazed part for about 1/2 hour, all the flux residue is gone. Mike

Use enough flux. It's much harder to remove if it's black and loaded with oxides. As Harold noted, boiling water and time will do the job -- and it'll do it faster if the flux isn't black. On work that will stand quenching, I've found that most or all of the flux shatters and falls off when quenched -- if it isn't black.

Making the material go where you want it to go is a matter of heat control. It will "follow the heat". There are masking materials available, e.g. "Heat Fence". (Found at welding store) I have a jar of it but I haven't tried it yet. I'll try it next time I braze something.