Posted by Chris G on November 19, 2002 at 12:02:10:
In Reply to: Patina quirks posted by Angel on November 19, 2002 at 10:11:05:
: Christine, I can't talk about this problem from experience because it has NEVER happened to me. I've tried many times to duplicate the glass discoloration problem in my little glass studio but it just won't happen. So, I will give you all the theories I know about why. Keep in mind that this applies to BLACK PATINA, because COPPER is another entity altogether. Black is an acid that etches a chemical reaction into the metallic solder. Copper is a 'plating' that sits on the surface.
: 1.) the WATER theory. Some regional waters (well water esp.) contain minerals which react with the patina and/or flux causing the "rainbow" discoloration effect. This is more likely to be an overall discoloration. Sometimes is removable early into the problem...often not.
: 2) Some GLASS...esp. REDS, BLACK and Greens are manufactured sith a mineral based pigments. This reacts on the surface with patina to cause a problem. Probably, it's the combination of the metallic solder. acid flux and acid patina that does it. You're MUCH more likely to see this happen immediately and it's probably as permanent as any stain. Doesn't come off with patina removers, toothpaste or polishes. You're stuck with it.
: 3) if your patina DRIES on a piece it's MUCH more likely to react with the glass. This usually occurs just at the edges of the solder and can often be removed with the cleaners mentioned. The cure for this (assuming you don't have any of the other problems) is to apply patins QUICKLY. Forget the business of putting it on with Q-tips etc. Use several cotton balls or a rag to get it on fast...and RINSE it off the glass with water almost immediately. There's NO WAY you can avoid getting patina on the glass, so just be sure it stays WET. If the panel is large, do one side and RINSE before you do the other side.
: The point is NOT to allow any drying of patina and minimum exposure time for the glass. Some people even put the panel in a sink and POUR patina all over it (messy, messy). Most of us do what we call "wet-slopping" of a LOT of patina with immediate rinsing. However you do it...DO NOT let that patina dry on the glass. You're not taking any patina off (unless you rub at this stage) because it will already have eaten into the solder in the minute or 2 it takes to go from application to rinsing. Let the panel drip-air dry.
: 4) Preliminary cleaning of a panel is essential for good patina and avoidance of problems. Try to Patina the same day you solder. I WASH (neutralize) my projects with Household Ammonia and HOT water (and a soft tire brush), then Dawn dishwashing detergent with another HOT water rinse. This leaves your solder seams shining like silver and they're VERY well prepared for any kind of Patina. If you delay a day or so between cleaning and patina you'll need to clean the solder with steel wool or a nylon scrubbie pad because solder begins to oxidize as soon as it's cool. Neutralizaion is ESSENTIAL for good patina. Commercial neutralizers, AMMONIA or baking soda (if you don't mind trying to get the powder residue out of the panel crannies) all work. I like ammonia because it cheap, always available (in the grocery store) and is a stronger neutralizer than either of the 2 alternatives...leaving NO residue. IF you ever decide to use ammonia to remove stains (which it won't do) pour it on the whole panel and scrub with a soft brush...it's great for panels and the q-tip thing is a throwback to your old-fashioned teacher who probably believes ammonia should NEVER be used on SG. Maybe not if it's waxed, because it will remove wax, but othewise, it's the best cleaner-neutralizer out there.
: Most of the people on the forums let BLACK patina "cure" for 12 to 24 hrs AFTER they rinse. This lets it work deeper into the metal and gives a more permanent, deeper color that resists being removed by the polishing step. I also NEVER add Zinc framing until after the panel has been patinaed and re-neutralized. It's just another metal to react and metallic inter-reaction is the base of the problem. Of course, I HATE patina on Zinc (actually don't like zinc at all) because it doesn't work and looks UGLY unless you tin the whole frams first and that's also UGLY.
: Now, I have to tell you that I don't get discoloration and I don't get oxidation crud on panels so I think I have a comnbination of technique prevention and luck. The water in this area which is not fit to drink is fine for washing stained glass panels. Go figure.