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So, let's get right into this week's question. It is from Marie-
Hi auntie EM!
Love the blog and had a question that's been haunting me for a while. I oxidize sterling silver a lot in my work, and find that the results can vary greatly. I'm trying to figure what I'm doing wrong when the results aren't as great. Especially on CHAIN!
Sometimes, I get a great dark grey finish on my chain and it's not dull and it's just great. BUT, there are other times that I get a dull light grey finish with lots of flakes coming off of it! I also notice sometimes that the chain is not evenly darkened.
Here are a few things I've tried to do to improve my results:
- I use heated water with a gel sulfur dissolved into it
- I put my chain into a tumbler first to clean it off
- I dip the chain into the sulfur for 10 sec then dip it into water, alternating until the desired darkness is reached
Good question Marie and a problem I have run into myself. I think I have figured out how to deal with this situation. First of all, let me say that it sounds like you are doing a lot of things RIGHT. You want to use hot water (mine is near boiling temp- I heat in the microwave). Here's some things I think might help you-
First and foremost- invest in a good soft brass brush. Use it for finishing only. I have one from Rio that I love. There is also a smaller one available for more delicate work. Not the stiff kind you get at the hardware store, that's for other things. This will help you to get much better results.
Let's start at the beginning. Heat your water nice and hot and dissolve your liver of sulfur (LOS). DO NOT make it too strong. If you are seeing flaking occurring on your pieces it is because you have built the oxidation up too thickly. A thin coat will not flake. Thick oxidation occurs by making your solution too strong or by leaving the piece in too long. As a general rule, I like a golden yellow to my LOS that I can still see through. It should not be dark or murky.
BEFORE you dip your pieces (especially chain)- clean them with your brass brush and some liquid dish soap - just a little on the brush will do. I use Dawn because it has no oily stuff in it (like hand moisturizers etc) that will inhibit proper cleaning. Ivory will also work. This will get all of your finger oils, sand paper residue, and polishing compound off your pieces. This stuff you can't see is to blame for many uneven oxidation problems. As a note to your specific question about chain- I have found many manufacturers have a polished coating on their chain and this inhibits the LOS from doing it's job. I think this is what you are running into when some of your chain will not oxidize properly. I either brass brush the chain or I take pumice in my fingers and run the chain through a couple times until it gets clean. I don't think tumbling the chains is getting rid of this polishing compound well enough. A couple runs through my pumiced fingers has never failed to get an even oxidation on chain for me.
Once your pieces are nice and clean, then start dipping them in your solution. I usually let the piece sit for a minute or two, take them out and brass brush them (with a bit of soap) and repeat until I get what I am looking for in terms of color. The brass brushings in between the dips continues to keep the oxidation even. Believe me, it really helps!
I am sure you have noticed that when pieces are sitting upon other pieces that those areas do not oxidize well. To deal with this problem, I make sure that my pieces are not touching and that I flip them over during subsequent dippings to be sure it is nice and even. This is especially a problem for chain. There is no way to oxidize it without it laying on top of itself. Make sure you keep stirring your chain with your copper tongs and this will help oxidize it more evenly.
Please note that if you have fire scale on your pieces, this will take up the oxidation more than the non- fire scaled areas. Many people think that liver of sulfur will help to cover fire scale and they could not be more wrong! It is not a substitute for good finishing. If you are doing everything above correctly and you are still seeing uneven oxidation, please take your pieces out into good light and look for firescale. It could be your culprit.
I sure hope this helps you Marie.
Until next week, happy metalsmithing. Please ask some questions so we can continue to write our weekly blog.