Hi everyone,
I have a question here, I put some silver discs into magnetic tumbler to make them shinny, the discs have patterns, now I want to remove the shine from its background, I want to make the background to its original colour from casting, what can I do?
I tried to black polish it, heat it up, put it in hot pickle, it doesn’t wor, it’s still shinny.
Thank you if anyone could give me advice.
Try some liver of sulphur,that will blacken the background.
Sandblasting with very fine grit will give you a similar frosted look as that of silver fresh from casting. It will not be as white, but it will contrast nicely with the polished surfaces.
After sandblasting emery and polish the raised surfaces by hand, on medium held flat, leaving the background untouched.
But I want to keep background white
That is what I want, but I don’t have sandblast
You might try using something like a rotary fingery thingy on the background to rough up the surface. Then burnish the raised designs to get a real shine. Test some of the ideas on a scrap metal to get a matt surface on the background.
A fine frosting wheel could have a similar effect to sand blasting and as others have said, you can then polish the raised areas.
If using sterling and you want a white colour you should be able to achieve a white firescale through heating.
You could try depletion gilding. If it is that white satin look that you are trying to obtain. Essentially you repeatedly heat and anneal the piece, pickling off the oxides. That will leave you with a thin fine silver surface to the entire piece. This should have a sort of matte/satin look to it. You can then burnish the highlights that you want to appear polished.
OK, so I know what depletion gilding is and how to do it, but so far we’ve also had a recommendation for sand blasting, one for a “rotary fingery thingey” and another for a fine frosting wheel. I thank the contributors for those latter three ideas, but the devil is in the details and I don’t know: a) what kind of sand blaster we are discussing or what kind of media is being suggested or what kind of hood or chamber the contributor uses; b) what exactly a “rotary fingery thingey” is (split shaft for sandpaper on a Foredom?? diamond fly cutter?? or ???); or c) what a fine frosting wheel is, either. Forgive my ignorance and my carping, but could the respective and respected fine craftspersons respond with details of their methods and equipment? Thx, royjohn
I’ve used a very fine grit bit had a bullet shape on ny foredom on a silver wedding band it frosted the outside i then used a nearly smpoth file to angle the edges and bring back the shine there. Those bits for a handpiece might work depending on the scale of the job. Just a thought.
Aaron
If I have to sandblast something I’ll job it out. I don’t need that kind of finish often enough to purchase the equipment.
I think depletion gilding is your best bet. It will come out of the pickle with a nice matte white finish, after which you can polish just the raised bits. If the top of the design is flat you should emery with paper held flat, for instance on a glass plate, and polish on a split lap to keep the surface flat.
Which brings up a questions about depletion gilding I’ve always wondered about…if the pure, frosted silver surface is actually a silver plate of sorts over a sterling interior, is there a possibility that years of wear will expose the surface underneath, which is a sterling, grayer color? If you’ve established the depletion gilded layer by several cycles of heating and quenching, is the layer of silver thus obtained as thin as typical silver plate done by electroplating? Anybody ever have a customer come back with an article whose depletion gilded surface had worn through? -royjohn
I heat it and anneal it, I did twice, it still looks shinny, only a bit yellow. How many time should I heat it? How big the flame should be?
google “fine frosting wheel” and its the first thing that shows up. over explaining can cause more confusion and op can always ask more questions for clarification.
The heating to bring out firescale i suggested is actually depletion guilding, i apparently never knew the correct term! Learn something new and all that…
Elliot’s suggestion is what I would try.
But if you want to try depletion gilding or surface enrichment, use a search engine to research it.
You need to heat it more than twice. No one can tell you exactly how many times it will take. It might take 10 times. You stop when it is the white color you want.
You need to remove the oxides between heatings and in addition to pickling, you need to scrub it with a brush …but not a brass brush because it will impart a yellowish color on the white color you are trying to create.
The important thing when depletion gilding is to make sure that the material is oxidizing when you heat it. Avoid using a reducing flame as it will greatly increase the number of times that you need to heat and pickle the piece. It is also important to pickle and not just water quench. Depletion gilding works by dissolving the metal oxides that are created under heat when O2 is present, leaving only the more noble metals. The layer and character of the surface will vary depending on the number of times it is heated and pickled, as the amount of noble material remaining on the surface will be greater the more times it is put thru the process. You can go too far and wind up causing reticulation on the surface of the piece, but that is in extreme cases. I would say the surface is thicker and more malleable than an electroplated surface. It is also not a single uniform layer like electroplating is, so the process permeates the work piece rather than simply being applied to the surface of the work piece.
Important to know that the white matte color from depletion gilding is only a surface effect and it will disappear with wear (as will any super shinny polishing)…especially in a ring…a pendant that is less ‘worn’ will be more persistent. Better answer (to me) is to start with a matte finish in the first place if you are hoping for a consistent look…The 3M scotch pad disc wheels will deliver that…and easily renewed.
Hi Jon,
Oh, sorry for the hijack if OP is the one who is supposed to ask for clarification! I did find the fine frosting wheel on Google search, but the ones I saw were about US$30, and I also found this link to a prior thread on achieving a satin finish:
https://orchid.ganoksin.com/t/frosting-finishing-using-flexshaft/28931
Evidently lots of other options…
Best,
royjohn
Why not skip the tumbler and just polish the surface you want shiny? If the tumbler is making the whole piece shiny, and want only the raised surface shiny and the lower bits to look like they were before the tumbler, skip that step. Seems over thinking and working at least to me.
Aggie
A technical point:
When a depletion-gilding-type process is done on sterling silver to create a pure silver surface it’s called ‘blanching’. The word ‘gilding’ refers to creation of a gold surface.
Janet in Jerusalem