Columbia BI horn polishing

[Phono48]

Phono48, I thought about stripper, but was concerned about it's effects on the plating. I was working on some dresser hardware once and stripped the plating right off with stripper. Do you have a brand that you like and have used successfully on plated metal?

I use Nitromors, but that may not be available in the States. I often use it to remove the remains of stubborn felt if I have to strip it off an HMV turntable. It has never touched the plating at all.

[Phonolair]

One thing to be aware of when polishing is not to polish thru the nickel plating into the brass.
This nickel plating is pretty thin. If you're polishing by hand it won't be a big problem, but if you're polishing with power tools it'll be easy to polish away the nickel into the brass.

Larry Crandell

[Curt A]

I cleaned one up last year with the same coating. I used straight ammonia and it worked well... other than the fumes.

[Edisonh19]

Nothing seems to be touching it aside from elbow grease and MAAS polish. I cant locate Flitz locally, and denatured alcohol did nothing. Nevr-Dull got it to some extent, but this coating is a real pain!

[wjw]

I cleaned one up last year with the same coating. I used straight ammonia and it worked well... other than the fumes.

What Curt said. If the coating was applied back in the day it might be shellac which ammonia dissolves nicely.

[Edisonh19]

I read that ammonia can damage the plating. Is that a real concern or just another piece of internet misinformation? I'm surprised that denatured alcohol didn't impact the coating at all. The outside of the horn is coated in a brownish paint (like aged brass). Is that typical for these models or would the whole horn have been nickel? I've been at it for three hours and have cleaned only about 10 square inches of horn. Do you apply the ammonia with just a rag or something more scrubby?

[Lucius1958]

I read that ammonia can damage the plating. Is that a real concern or just another piece of internet misinformation? I'm surprised that denatured alcohol didn't impact the coating at all. The outside of the horn is coated in a brownish paint (like aged brass). Is that typical for these models or would the whole horn have been nickel? I've been at it for three hours and have cleaned only about 10 square inches of horn. Do you apply the ammonia with just a rag or something more scrubby?

The whole horn would have been nickeled.

Have you done any polishing on the outside, to see what lies beneath? If you find nickel, all well and good: if you find brass, that might mean that someone had over-polished it and taken the nickel off (alas, I've done that with my BI)...

Oh, and I have used ammonia on gold plating with no ill effect - and nickel is certainly tougher than gold.

Bill

[Edisonh19]

Thanks Bill. No, the coating on the outside is pretty heavy and uniform. Certainly not anything that accumulated over time, unless it was some sort of coating meant to keep the horn shiny that went brown over time. The machine was definitely stored in dirty conditions. The nickel plated rear mount hardware was so dirty that I had to use steel wool on it (fortunately no damage resulted). I will probably leave the exterior of the horn alone (unless I decide to use stripper as a last resort), the color doesn't bother me. The interior is very blotchy and discolored as it is. It looks like the coating was applied with a rag and just sort of swished around. I've managed to polish three small sections on three of the petals. The nickel is mostly intact and shines nicely, but you can tell that it's getting a bit tired. I'll try some ammonia when I get to the store to buy some. I still think it odd that denatured alcohol didn't even touch it.
Thanks!
Ed.

[phonogfp]

Check out this old thread on a different forum. Scroll ½ way down to my posts of Jan. 24 & 25 2009:

http://victrolagramophones.proboards.co ... rns?page=2

This looks like the brown stuff you're describing.

Good luck!

George P.

[Edisonh19]

George, that sure does look like the same kind of coating. I wonder what the heck it is? I'll have to read the article to see how he removed it. I'm concerned about rubbing through the nickel plate. I don't know how substantial it is. The coating on the back of the horn is so thick that I don't think I could get through it with just polish.