P90 Base plate material

[rakers]

good morning... does anyone know what material was used for early 60s Gibson P90 base plates??

I've heard both nickel silver and zinc plated brass. I tend to lean towards zinc plated something from the ones I've seen. Probably brass.

Any insight would be greatly appreciated. thanks.

[Bill M]

All the ones I have and have seen from the late 50's and 60's were brass with some type of zinc or galvanized coating.

[Possum]

...

I keep hearing nickel silver was used but never have seen this. If it was used did they zinc plate it as well???

[rakers]

Hey guys, thanks for the responses.

I'm with Possum, I've never seen nickel silver used for these base plates. From my experience it seems to always be zinc plated brass. I'm taking a 64 dog ear P90 to my plater today to get their opinion. I'm almost certain it's some type of brass. I'd love to send a plate off for metalurgical testing to determine the exact alloy but I just don't have any around I can sacrifice at the moment.

[rakers]

Surprise!! These are most definitely Aluminum.

[David Schwab]

Surprise!! These are most definitely Aluminum.

NOT! Aluminum would make the pickup dull sounding. That's why you never see it used.

I had a set from an SG years ago.. the ones that mount on the pickguard. They were nickel silver, but they did look zinc plated. The reason I know that they were not brass is because I cut the mounting tabs off one to make a Charlie Christian type mount that was suspended from an aluminum pickguard, and the metal was not yellow.

[rakers]

Hey Dave, you may be right. But here is what was done to test this and arrive at this conclusion on this particular P90 dog ear from 1964. This guy is very knowledgable and I trust his opinion until proven otherwise. He was adamant that the metal was aluminum. I asked him more than once if he was sure. ;-) It surprised me also.

We removed a sliver of metal from the base plate and placed it on a glass dish, put a drop of nitric acid on the metal. Result was shinier metal. Rinse with water, one drop of hydrochloric acid and the result was disintegration of the metal. Hydrochloric acid attacks aluminum, not brass or nickel-silver.

I'm wide open to anyone that has additional thoughts on this or has evidence that would dispute the result of my testing today. I just want to know the truth of the matter. At this point the evidence in my mind leans towards aluminum until proven otherwise.

[Possum]

....

Isn't aluminum impossible to solder to? I have a mid-60's, maybe even earlier P90 dog ear baseplate and its definitely NOT aluminum, for one thing it weighs too much, scratching it shows brass underneath, a lighter colored brass, not super yellowish. I have read some people thinking nickel silver on PAF's was aluminum for sure it never was. Aluminum should be easily identifiable by weight alone. Something is wrong with that test?

[Bill M]

Aluminum is impossible to solder to, but old P-90's were not soldered to the base plate anyway. They used a solder tab mounted by one of the bobbin mounting screws for the ground connection. I've never analyzed a mid/ late 60's P-90 base plate, but all of mine are 62 and older and they are brass.

[rakers]

guys, I tend to agree with what you're saying. Something just doesn't feel right about this conclusion.

More testing is definitely in order. :-)

Just don't KNOW for sure at the moment what these plates are made from.

thanks for everyone's responses. I appreciate the input.

[Possum]

...

Send it to a metals lab for analysis. Belwar has a guy who can do it for $40 I think. You can't dispute what they will find.

[EFK]

I just pulled out (3) 50s dogears and (1) from about 62-63. I scraped through the [what certainly looks like] zinc plating on the baseplates and every one of them is plain old yellow brass.

[rakers]

yea after a few missteps ;-) I'm back to thinking brass too. :-)

Not sure about the plating though.

thanks guys