Jupiter 9 aluminium corrosion

Mr.Takumi · Joined: 23 Oct 2011 Posts: 2

Hi,

I just bought a 1964 Jupiter 9 aluminium in M39 mount to use in my Pentax. I have got a M42 to PK mount adapter and I'm looking for a M39 to M42 adapter to put it between of them.

I'm curious to know if having three different metals in contact might produce some kind of galvanic corrosion. I saw a lot of "chromed" Jupiters that have a quite bad cosmetic condicion, so does anyone know something about this?

The M39 to M42 adapter I found in ebay are...

The black one. Probably the black paint will tear apart?
The aluminium one. Not very well machined but should work.
The brass one. Not very well machined as well.

I'm thinking about getting the aluminium one and don't store the body with the lens atached for a long itme, just in case.

Thank you in adavance.

Best regards.

Attila · Expire: 2025-11-18

Welcome!

Do you know it has two version with M39 mount ? One made for RF cameras it will be not works with your Pentax and one made for SLR.

Aluminium tube is sensetive for storing environment , this is only aesthetic problem.

NewStuff · Joined: 31 Mar 2011 Posts: 847 Location: Wales, UK

Although you will get Galvanic corrosion, it will be very slow. Once the metals are uncoupled, the reaction will stop. For short periods of time it will be fine, just remember to disassemble it after shooting.

Mr.Takumi · Joined: 23 Oct 2011 Posts: 2

Yeah, it's the Zenit version so it should work fine. It's in a rare mint condition so I hope to don't waste it.

I think I'll get the aluminium M39-M42 adapter. It'll be always kept with the lens, so it's better to use the most similar metal.

I'll take care of not leaving the Jupiter atached to the body for months, like you adviced as well. I suspect the K mount may be stainless steel...

Thank you.

Best regards.

poilu · Expire: 2019-08-29

welcome Mr.Takumi
you have a nice name,
sound like Takumar Smile

Sevo · Expire: 2012-12-03

You do not need to worry about that, unless you intend to subject your cameras to conditions where they'll fail quite soon in any case. About the only place where I've seen galvanic corrosion in otherwise good cameras are "Zeiss bumps" (the corrosion to leather covered aluminium rivets in steel camera doors) and aluminium filters frozen into brass lenses and vice versa.

When it comes to lens/body contact, you'd need constant humid conditions at the mirror box port to get any corrosion there - but these wreck electronics, lenses, finder optics and surface mirrors long before the mount starts malfunctioning.