zinc oxide powder on BF chassis

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chief mushroom cloud
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zinc oxide powder on BF chassis

Post by chief mushroom cloud »

Can anyone give me a rundown on this problem? I have a 66 BF Super here...and this shit is EVERYWHERE....it's like chalk dust...it's in everything..pots, tube sockets inside the cab....all over the chassis.
I read this was cheap zinc plating when Fender tried to cut costs...but I'd like to get the lowdown. The customer complains that after playing for awhile....the power drops and sound is real thin. I could see this 'white powder' in the pots...so I douched them...but can't replicate his complaint...I'm assuming this was the problem...but like I said..I need the real story.....
TIA
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Structo
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Re: zinc oxide powder on BF chassis

Post by Structo »

Could also be a conductive circuit board if it has been in moist places.
Tom

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chief mushroom cloud
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Re: zinc oxide powder on BF chassis

Post by chief mushroom cloud »

I was thinking that too. I'll take it out to garage and blow out w/ air compressor today.....
Don't overthink it. Just drink it.
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Reeltarded
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Re: zinc oxide powder on BF chassis

Post by Reeltarded »

Was the powder kind of like snowflakes on acid? Furry?
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vibratoking
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Re: zinc oxide powder on BF chassis

Post by vibratoking »

I've never heard of such powder. I have a 65 Super and there ain't none in mine. Just as clean as can be inside. Sounds like something was introduced at someplace other than the factory.
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Reeltarded
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Re: zinc oxide powder on BF chassis

Post by Reeltarded »

I have seen it though. Galvanic corrosion from dissimilar metals, especially zinc which is used as a sacrificial rust inhibitor in lots of industry, and boats, and water heating.

I have had stuck pots on guitars and amps that were just full of white fuzz, welded by it even.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
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chief mushroom cloud
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Re: zinc oxide powder on BF chassis

Post by chief mushroom cloud »

Reeltarded wrote:I have seen it though. Galvanic corrosion from dissimilar metals, especially zinc which is used as a sacrificial rust inhibitor in lots of industry, and boats, and water heating.

I have had stuck pots on guitars and amps that were just full of white fuzz, welded by it even.
it is like white fuzz
this is what I've found so far:
http://www.fenderforum.com/forum.html?d ... ber=661481
http://archive.ampage.org/threads/2/gag ... sis-1.html

it's pretty bad in the Super I have on the bench...I've cleaned most of it off the metal surfaces...but you can see where plating has discolored...

So I cut a line of it and rolled up a 5 dollar bill......
Don't overthink it. Just drink it.
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Reeltarded
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Re: zinc oxide powder on BF chassis

Post by Reeltarded »

Doctor told me not to snort that stuff because of the plate in my head.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
vibratoking
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Re: zinc oxide powder on BF chassis

Post by vibratoking »

Yeah, don't snort that stuff. Sell it on the street...sounds like there is enough for a set of NOS tubes.
SoK66
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Re: zinc oxide powder on BF chassis

Post by SoK66 »

My '66 BFDR came to me many years ago with a white powdery substance on some of the components inside the chassis, particularly on the plastic wires of the PT, OT & reverb transformer. Cleaned off fairly well but I was curious what it was. The amp had sat in a closet for what the seller said was decades. Came to me with new filter caps and a poorly installed 3 prong cord, but no other new electrolytics or replaced parts, and no sign that one of the original filters had blown. Some of the original bypass caps looked about to burst. I did a total recap and replaced quite a few resistors and ceramic caps that had drifted way off spec. Still the puzzle about the powder. DId a cap blow, did the PT short?

With the amp came an original power cord that had a replacement plug. (The original cords on DRs looked like something for a table lamp). Seller said By the time I got it that old cord had hardened stiff and the original plug had completely crumbled. There was more white residue on the inside of the cabinet where the cord had been coiled up, so I'm guessing the cord and plug deteriorating and off gassing produced the white stuff since most of it was close to the PT. Who knows?
TUBEDUDE
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Re: zinc oxide powder on BF chassis

Post by TUBEDUDE »

Mold?
Should have used Zinc Chromate.
Tube junkie that aspires to become a tri-state bidirectional buss driver.
Charlie Wilson
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Re: zinc oxide powder on BF chassis

Post by Charlie Wilson »

Hello, I live by the beach and see many Fender blackface and silverface chassis with the white powder. I think it has something to do with moisture and the hot dipped zinc chassis oxidizing. Do not, I repeat, do not get any of it in your nose(five dollar bill really bad idea 8)) or eyes. It burns like crazy. If you spray some Deoxite on a rag and wipe it the powder dissolves away. Same with pots and tube sockets.
CW
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