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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Stripping of bronze plating
Strip bronze from brass parts
Q. Hello all,
We are looking for a stripper or a process recommendation that completely removes an alloy of Copper-Tin-Zinc plating from brass parts without etching the base brass metal.
This is in order to be able to strip and replate process rejections from our bronze plating line.
Khozem Vahaanwala
Saify Ind
Bengaluru, Karnataka, India
2005
A. Hi Khozem,
Combination of hydrochloric acid, sulfuric acid and hydrofluoric acid in an electrochemical action should strip the deposit on brass substrate.
Well maintained stripping bath will not etch the brass.
Even though I haven't used this formulation to strip copper-tin-zinc alloy, this stripper will strip any deposit from brass.
Unfortunately I don't remember the ratio of the above acids (it's almost 4 years since I have used it). But if you play with these three chemicals for few days you can optimise the stripper bath.
Regards,
- Kitchener, Ontario, Canada
2005
A. I have to disagree with the stripping process aforementioned. Considering that bronze contains a lot of copper in the alloy and brass does too, I think it's extremely unlikely you'll strip bronze from brass and not damage the brass material. I'd do that on a very small scale first to make sure you don't damage the substrate.
Daryl Spindler, CEF
decorative nickel-chrome plating - Greenbrier, Tennessee
2005
Stripping bronze plating from steel parts
Q. It is being suggested to me that ammonia ⇦ this on eBay or Amazon [affil links] solution (specific gravity of 0.89) diluted to 10% with demineralised water could be used to strip bronze plating from alloy steel parts. I have experience of proprietary stripping solutions such as Enstrip S, but not of the above. Will this be acceptable for steel parts? And how will the solution evolve over time, i.e. does it just become ineffective and therefore need discarding or can it be replenished by adding fresh ammonia solution?
Simon Ford- Wolverhampton, UK
June 26, 2013
A. We used Pure Assay ammonia SG 0.890 with no dilution. It takes about five days in total. The ammonia was replaced daily, and the parts were agitated regularly. A light rub with "scotchbrite" was used to remove any black deposits left on the parts. No pitting or corrosion of the base metal was observed.
Jonathan Fletcher- Birmingham, Warwickshire, England
August 30, 2013
Proper solution ratio for stripping bronze plating off racks
December 20, 2016Q. Morning all!
I need some help. We just made some improvements to our plating strip tank. We've added a Carbolux unit to pull out carbonates which significantly lessens our disposal and haul-off costs.
What suggestions can you guys give me to help optimize my cyanide strip solution to remove bronze from our plating racks?
What's new for us is actually controlling the chemistry for the stripping solution (1100 gal of sodium hydroxide & sodium cyanide @ 140 °F). Before the Carbolux, we ran the tank until it "died" (the carbonates maxed out) and stopped stripping racks. We didn't really worry about anything but the carbonate levels (testing-wise). We would just dump the tank and re-charge fresh.
Now, we're adjusting chemistry but we're not seeing the expected bath life (we are able to get double to triple the bath life, but expected at least 4 weeks min). The solution is doing odd things, like leaving a heavy white film on the racks (even when the carbonates are relatively low) after they are pulled -- fully stripped but coated.
I'm guessing that it's a ratio issue with the chemistry, but I haven't had a chance to really test it.
Can you all help me out?
Thanks!
Dawn
- Bellaire, Michigan
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