Posted by Angel on December 16, 2002 at 23:18:40:
In Reply to: black patina posted by Chris on December 16, 2002 at 21:41:56:
Chris I'm going to jump in here and lay out a few well used techniques for you. I think you're confused about the chemistry and mechanics of patina.
FIRST...you MUST neutralize your flux after soldering. I use straight household ammonia for this but you can use a commercial neutralizer like CJ's (ammonia ia stronger and cheaper and if you run out it's in your local supermarket). After you neutralize by pouring on some ammonia and scrubbing lightly with a soft brush, RINSE the panel with HOT water. WASH it with a non-oily detergent (like Dawn) and rinse agin with HOT WATER.
Pat dry and allow to air dry. If you patina the same day you neutralize and wash you don't need to scrub the solder seams with steel wool or anything. Solder begins to oxidize as soon as it cools, so if you let your panel sit for a day, you WILL need to clean it with steel wool or a scrubbie pad. Just let your panel air dry and apply black patina with a rag, cotton balls or anything you can slop it on and keep it WET. NEVER let patina dry on the glass (this is one of the main causes of glass discoloration). Slop it on (don't brush it on...that doesn't help and it can even lighten the result). RINSE the patina off IMMEDIATELY with tepid or cool water to get it off the glass.
DO not rub at this point, but let it air dry.
NOW you let it sit overnight...12 or 24 hrs. Black patina is an acid that etches into the metal. Most of its work is done as soon as it touches the solder, but letting it sit after you rinse it off initially will prevent it from rubbing off when you wax and gives a deeper color.
After that "incubation" period neutralize again with ammonia or CJ's and wash with Dawn detergent. Once it's air-dried you can use any good carnuba based wax like Kem-O-Pro or Mother's car wax (some people even use pledge).
If you get a clear picture in your mind of the acid chemistry that turns metal black (with a little help from copper sulfate) your own good common sense will lead you to use it properly. ACID and METAL plus OXYGEN produce corrosion...so you need to NEUTRALIZE all acids...and that includes flux and black patina. Protection from oxygen is necessary to prevent air corrosion and that means you need a coating of wax to seal the seams.
I NEVER get crud on my panels and if you neutralize, wash and wax, neither will you.
NOW...when you get to COPPER Patina, come back...we'll talk...it's a WHOLE other ballgame.
: Thanks for responding so quickly Gary. Yes, you are correct I am heavy handed with the flux. I'm a new guy on the block so I'm learning the hard way. I used Novacan patina. I guess I'll try again. I hope I don't ruin my nice piece I worked so hard on it. I was told that for black patina I should leave my project overnight after I've soldered it and scrubbed it clean. Then the next day put the patina on. Also, should I put it on with a Qtip or something or do what I did with the other one .....I scrubbed it on with a tooth brush, waited a few minutes then rinsed and washed. This time I'll try and go lightly with the flux too.
: Thanx Chris