Acne on Chrome over Aluminum snares - Page 1

Hi guys,

I know this is an old, well-worn topic, but I played a backline kit last week and it included a Monroe, NC badged Supraphonic. What surprised me - or maybe shouldn't have surprised me - was that this snare had the same acne that we see on 1960s-1970s Ludwig COA snares.

Question 1. Did Ludwig ever resolve the galvanic corrosion problem with its COA snares? I realize it takes some years of exposure before the acne starts to show, but I would think that improving technology would have resolved this before the 1980s.

Question 2. We all hear about Ludwig's problems with acne. But I've never heard any mention of this problem with other manufacturers. Did Slingerland, Gretsch, Rogers, etc all have better processes that eluded Ludwig's production?

Thanks in advance. Regards, mb

Chrome plating aluminum is as big a challenge today as it was back in the 60's. In short, alumimum quickly oxidizes and this will weaken the adhesion of the plating to the aluminum. The aluminum has to be treated with a zincate solution before plating. If the plater gets it wrong, the plating will not "stick" to the shell as well as it should. This can cause large scale failure of the chrome.

Another thing that is the biggest issue that causes pimples, is that chrome plating isn't 100% impervious to moisture. If it was, we would never see rusted chrome stands, rims, pitted lugs or rusted chrome bumpers on old cars. When chrome isn't kept clean, dirt deposited on the chrome will retain moisture and allow it to seep into the chrome. When it gets to be base metal it will corrode. Steel will rust and aluminum and zinc alloys will corrode (bloom). The corrosion converts the base metal to an oxide that is physically bigger than the base metal it consumed so it will blow the chrome right off. The corrosion will work it's way back out and start to spread on the plated surface and also start to separate the plating from the base metal given enough time.

If you have ever cleaned the rust off a rusty stand, and found that it looks really good other than a few very small black spots, this is why. Once the corrosion had started to bubble the plating, nothing can be done about that but any corrosion on the surface only can be removed.

So this is a long way of saying, if you want to keep your Supra, or any chrome parts for that matter, from getting acne, keep the shell really clean all the time. And keep it away from moisture. A dirty chrome plated aluminum drum in a damp basement is a bad combination. Keeping the dirt, sweat and other grime off the plating will go a long way to keeping the pimples away.

I don't think many of the other manufacturers made drums with chrome plated aluminum shells. I know Premier did, and Gretsch had a few maybe. Slingerland didn't to my knowledge. Premier aluminum shells suffer from the same acne problems as Supras.