Stopping Antiquing Solution

I'm using an antiquing solution to color mounts and need help figuring out how to stop the coloration process. I dip the mount into the antique bath, then dip into water, lightly scrub with a sponge to take away the glimmery patina, and then dry and put away. Weeks later, they turn silvery and uneven. Recently, we started using a randomly concocted baking soda + water bath (the company that sells the antique solution did not know what ratio to use of baking soda to water) but I'm hoping someone has had more experience with this and can advise - does it work? What ratios do you use?

Thank you!

Hi,

I'm assuming this query is coming from the new Alaska State Museum project that I've been a part of, so I'll answer based on what I know about your process.

To start with, is this a new problem? Have the mounts that were patinated previously shown the same sort of color changes? If so, when did you start noticing the change? If not, what has changed? Is it time for a new batch of patina? At the production rate of your project, you may want to renew it regularly as the specific chemicals will get used up or contaminated. Are there other possible sites of contamination such as the rinse water or the abrasives in the blast cabinet?

I'm also wondering if the baking soda advice was something from the manufacturer that was based on their science, or if it was something that somebody just thought might be helpful? I only ask as the patina solution you were using was purchased from Rockler, and is probably a re-labeling of a product from someone else. It would be good to see if you could find out the specific manufacturer and see if you can find your way to their tech support. In other manufacturers instructions, I've never seen anything needed but a thorough water rinse to stop the process.

The best company I've run across is Birchwood Technologies (formerly Birchwood Casey). They've got some great technical support docs on their site. http://www.birchwoodtechnologies.com...ing/index.html

Sculpt Nouveau is another good source for patinas and information. http://www.sculptnouveau.com/instructions.cfm

Jax Chemicals is the third source that I've used and I have generally liked their products. https://www.jaxchemical.com

Please feel free to give me a call and we can see if we can further troubleshoot the problem.

Jamie 206-954-4141

Hi Jamie - you caught me, it's Ariel! I started noticing the change a couple of weeks ago on some of the mounts I did right when we started antiquing. We just replaced the solution (there was also residue - brass and probably from the scrubber sponger we have been using to dull the patina) so I'm hoping that will help. The color has turned that silvery-dark purple in blotches, especially on the darker mounts. Which makes me think that the antiquing is continuing to affect the brass mounts after it has been rinsed.

The baking soda was on the label of the antique solution. We called the manufacturer and they had no "recipe" for mixing it so we just guessed. I'll look into it and see if I can figure out the specific manufacturer. I'll also look through Birchwood Technologies and the other companies you mention... thanks for the resources. Thanks for answering my post!

I feel that two things may be happening. Especially since this effect was noticed on the early mounts done in the patination process, I'd venture to say that the initial surface prep before immersion in the patina solution was probably a bit uneven. Also, trying to get a dark coloration by keeping the brass in the solution for long periods can definitely lead to the purpling you are seeing, and can go all the way to silvering. I would recommend re-scuffing with fine scotch-brite and doing a series of shorter dips with washes in between to try to achieve the color you want.

The baking soda solution does make some sense as the patina solution contains an acid like Selenic acid and the baking soda would be acting to neutralize it. It would be interesting to do some experiments with and without a soda bath to see if there are different outcomes over time. I look forward to seeing what you discover.

I'll try the shorter dips and scotch-brite. Thanks for the suggestions.

We only just started using the baking soda a week ago so I'm very interested to see if it makes a difference. I think it would be good to experiment with that as well. I'll let you know what we find out!