My first bronze casting

[F.C.]

If you're wanting the dark brown patina (with high polished or machined/sanded lettering surfaces) use sulphated potash. Mix the yellow crystals into a volume of water you intend to use (I tend to mix up about 16 oz volume). Add the crystals and stir keeping an eye on watching them desolve. Once they reach a level of solution where the crystals will no longer disolve but lay on the bottom of the vessle then add just a smidgeon more water to enable them to mix with the water molecules then you're done. From there wire brush the bronze piece with a soft wire wheel or hand brush to remove any surface oxidation then heat the piece of bronze up to a temp where water will steam off it when applied then (using a clean cheap throw away brush (or spray bottle)) commence to apply the patina solution as evenly as possible (while keeping heat applied to the bronze) until the entire piece becomes dark chocolate brown. Wire brush by hand once the piece is entirely dark (while the solution is still wet on the bronze surface) to ensure even application and continue to apply more patina as needed. Then let it sit and dry. Afterward, immerse the bronze in a bucket of clean water and (with as soft of wire brush you have) remove the patina to a an even color you desire, then transfer it to another bucket of clean water and rinse well using a clean paint brush to scrub softly with. Then, once more, rinse the bronze under a faucet of steady clean water. YOur piece will then be uniformly brown at this point. Let it dry. Then carefully sand off the lettering faces and borders and either leave it sanded in appearance or carefully polish the highlighted surfaces to a mirror gold shine. Once this is done apply carnuba wax to a buffing wheel and polish the entire piece to a gloss appearance, or clear coat it with a spray acrylic if you don't have sufficient tools to selectively polish the high points without removing patina where you otherwise prefer it to remain. At this point you're done!!

[F.C.]

If you're interested in a mottled, marbled, splash effect patina (of black, turquoise, gray and white) use cupric nitrate mixed with water as described in the afore mentioned patina solution. With this solution you need a respirator as the fumes it creates are caustic, or patina outside in a breeze crossways to you and the work you are attempting. Using a hand held torch heat the piece to a temperature where water will spitz, hiss and boil as it's dribbled onto the surface. Begin by making the bronze surface entirely flat black. Rinse and brush with a stiff brissled throw away brush. Re-heat the piece again but only to a temp where the water that's dribbled will only bubble and boil, not hiss and spitz. I merely dip a 1" throw away brush into the patina solution and then dopple on water splotches where I want the effect to occur. Watch as the heat keeps the water from spreading but allows it to remain in a random blotch and boil itself dry. The outter edges of the water blotch will appear white leaving the inner portion of the blotch a mottled assortment of turquoise and gray with the black background exposed to some degree. Overlap your blotches as you patina the piece, don't worry about the lettering, allow it to patina as well. If you patina too much it will become virtually all turquoise. Too little it will look black with white overlapped circles of gray and white. Once you have the effect you desire cease with the application, allow to dry, then rinse (as described before) using a throw away paint brush to clean and softly scrub with.

If you want the mottled/marbled effect to have a tortouse shell (green marbled effect) patina your bronze first to a brown using the sulfated potash then once dry and cleaned, apply the cupric nitrate solution as described above. Clean and seal the patina as described, before, in the previous instructional post.

[F.C.]

If you want it all solid black background with high shined raised lettering, use the cupric nitrate solution and apply it to a heated surface that will boil and hiss the water solution applied. Keep doing this untill the entire piece is uniformly black. Rinse and clean, rinse and clean, then seal as described in the afore mentioned instructions.

[mite5255]

Thank You

[mite5255]

If you're wanting the dark brown patina (with high polished or machined/sanded lettering surfaces) use sulphated potash. Mix the yellow crystals into a volume of water you intend to use (I tend to mix up about 16 oz volume). Add the crystals and stir keeping an eye on watching them desolve. Once they reach a level of solution where the crystals will no longer disolve but lay on the bottom of the vessle then add just a smidgeon more water to enable them to mix with the water molecules then you're done. From there wire brush the bronze piece with a soft wire wheel or hand brush to remove any surface oxidation then heat the piece of bronze up to a temp where water will steam off it when applied then (using a clean cheap throw away brush (or spray bottle)) commence to apply the patina solution as evenly as possible (while keeping heat applied to the bronze) until the entire piece becomes dark chocolate brown. Wire brush by hand once the piece is entirely dark (while the solution is still wet on the bronze surface) to ensure even application and continue to apply more patina as needed. Then let it sit and dry. Afterward, immerse the bronze in a bucket of clean water and (with as soft of wire brush you have) remove the patina to a an even color you desire, then transfer it to another bucket of clean water and rinse well using a clean paint brush to scrub softly with. Then, once more, rinse the bronze under a faucet of steady clean water. YOur piece will then be uniformly brown at this point. Let it dry. Then carefully sand off the lettering faces and borders and either leave it sanded in appearance or carefully polish the highlighted surfaces to a mirror gold shine. Once this is done apply carnuba wax to a buffing wheel and polish the entire piece to a gloss appearance, or clear coat it with a spray acrylic if you don't have sufficient tools to selectively polish the high points without removing patina where you otherwise prefer it to remain. At this point you're done!!

Frank is the sulphated potash garden fertilizer

Mike

[F.C.]

That I don't know, Mike. The term "sulfated potash" is sort of a slang term many people use, but it is also referred to as "Sulfurated Potash", or...most common (and probably the more accurate term) "Liver of Sulphur". Google that and you'll come across recipies on how to make patinas using various chemicals (in combination with the sulfur compound) yourself.

[mite5255]

I tried a sulfated potash yesterday ( garden fertilizer http://techsheets.simplot.com/Best/74139_sop0050.pdf ) and it ended up with a white powder all over the casting, but when washed it had a soft brown patina , I'll post a photo later

Mike

[F.C.]

Well I'll be danged... ya taught me something I didn't know. THANKS!

[Rasper]

Garden fertilizer? Who'd a thought?

R

[mite5255]

I'm assuming it is all the same stuff, I'd hate to be held responsible for ruining the lady's prize garden
Photo is my sample, top has wire brushed only, bottom has sulfated potash applied