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I think I'm posting this in the correct place. Anyway, during last Saturday's 'Dive Tribe' I was discussing with Bob about using aluminum with brass materials. The reason being that when machined aluminum parts are interacting with other machined aluminum parts, 'galling' occurs and eventually the parts lock up. This happens very easily between machined aluminum parts that aren't precisely fit. With tanks, cars, trucks, we'd use brass to prevent this, and it worked for us. Bob contested the use as it will produce an electrolytic-effect between the two metals. Little did I know how true this is, so I delved into it at work the other day. So, this is very true between all metals to some extent. Some, the effect is so small you don't have to worry about it. I thought that was the case between brass and aluminum...it is, and it isn't. So I looked it up on the 'Galvanic Table' and saw that brass and aluminum are midway in the table...so that's enough to be worried about it. In fact, when the metals are wet, its when the electrolytic-action really comes into play. When dry, you don't need to worry about it. So with subs, forget about using them together. Brass on brass will stick, but it's only oxidation or verdigris that can be handled by oiling. Now if I had aluminum machined parts going together on a sub, I'd use Delrin/Teflon/ Acetal as a friction barrier which can be machined and provides great wear characteristics and not worry about galling. You can get it in very thin sheets, or blocks that can be machined.
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Thanks Jake!
And like I mentioned in DT, I have a working telescoping 'snorkel' that I use to see where the model is sub-surface. It manually slides up and down when needed. Over time this needs service to remove oxidation as the oxidation causes it to stick. Lubing just doesn't do it, besides, have to keep many things up with maintenance anyway.Last edited by Ken_NJ; 12-21-2024, 03:36 PM. -
The Marlin. It actually has the periscope and snorkel within brass tubes, brass on brass. Once removed, the inner sliding tubes are black. To clean I sand with 400-600 grit wet\dry to a nice shine and reinsert.Comment
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Ken,
A very light coat of marine grease (blue stuff in a tube, NOT the 35lb can of USN Termalene!) on your brass tubes will help immensely.Comment
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I'd like to suggest a light coat of no oxide grease as used in aviation or aluminum wiring Grease as used in transitional electrical work.
I'm sorry I missed last week's dive tribe... I was busy tasting rum in Costa Rica...Last edited by Bob Gato; 12-23-2024, 08:08 PM.Comment
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A simple bonding jumper will help also but most of the time that is totally impractical -the above greases will accomplish the same thing. And if I had to make a SWAG, for those of us using megahertz radios the above greases should also help prevent glitching due to the rattle of metal against metal, not so much a problem in subs but certainly in RC airplanes and surface boats.Comment
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Ken, you can probably get away with just doing your pre- and post-mission maintenance with nothing more fancy than a light oil like 3 in 1, or even something more viscous as needing like 5w50, 10w30 (I'd see which one reacts better in a water environment. You can use vegetable oil if you have any plastics that would be attacked. With tanks, we break-in the motor gear sets in automotive oil and then let them dry and a fine coat of oil remains for lubrication. I'd stay away from mediums that are too viscous, Termalene was mentioned not to use and this is exceptionally correct as it was removed for use on hydraulic hoists. If the metals are wearing too badly, you can just keep sanding them. Best story about your Marlin is the one with the catfish inside.Comment
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