Hello,
I'm in my second year of ownership but really just my first one not farming 100% of the work out. Attempting to think for myself and understand what "the right way" is vs "the way everyone tells you to do it" and ensuring I'm on the right part of that fork. I've been working all these points myself for some time and have come to obstacles to moving forward for most of these. Certainly there is information "out there" on all of this but the vast majority is lacking any connection to specific cause/effect motivation. Hopefully it's not a mortal sin to collect a number of questions under a single post.
So... in no particular order. Breaking the following sections up so I can spread them over the appropriate sub-forums.
BOTTOM PAINT
1. I've got Micron CSC on my hull and except for 2 square inches, it's in good condition. I spoke with a gentleman at Interlux support who said I didn't need to sand it per se but merely to "rough it up". Is a palm sander overkill? I'm in that "used up" part of my life and machinery does make life better. If not a sander (I'm rich in 80 grit pads btw), then what might you suggest?
2. Order of operations - zincs and paint. I see advantages to doing it both ways but will probably put the zincs on first and delicately cut in around them as I paint... is this anti-stupid?
3. Paint interaction with bonding system - a paint with copper in it sounds as though it has the potential to interact with the bonding system. Any considerations here?
4. While I've been warned away by friends from doing this because of "looks", I'm thinking of doing two coats over the dark blue paint on there now. First a red layer (1 gal) with deployment priority to the high-wear areas, going as far as the gallon will go. Then using applying dark blue (sounds like 1.5 will handle completion). The idea being to have an obviousness when paint wear has moved to an actionable level. I'm sure I'm not the only one that has thought of this but then.. my idea for the V8/6/4/2 engine was later proven to suck to the moon by Cadillac saving me considerable personal embarrassment from my high school mates. So... anti-stupid or am I missing some basic fact and should just do it all one color like everyone else?
ELECTROLOSYS, BONDING AND GROUNDS
As I'm trained in electrical engineering, I find the myriad of things that can screw you royally under this subject fascinating... how the sets of best practices for the various domains (shore, boat AC, boat DC, bonding, signaling, etc) must all coexist sans significant pathologies.
1. They say "check the bonding system before you paint". Is there some particular pathology that drives this point? Check the totality for perfect functionality? I've been searching for a system check procedure that I can accept (i.e. a cause/effect connection to specific faults I want to discover and correct) but mostly all I find is hand waving that falls into the "the way everyone tells you to do it" bucket. Suggestions/pointers deeply appreciated.
2. If I understand a basic principle for mitigating vulnerability to electrolysis, it is that if one can isolate a metal in contact with sea water that that is preferable to bonding it and expanding the number of places a failure can occur. So... my skeg and rudder appear to be isolated from anything else in my boat (assuming hydraulic fluid is a poor conductor). Why would they bond it? Why would they put zincs on it? It isn't connected, or at least seemingly so.
3. There's a brush in the engine room bonding my prop shaft. There's not quite 1.5" of shaft between my prop and where it enters the boat. I can turn a little bit of a 1.5" zinc off on my lathe and make it fit. Do you see any problems with adding a zinc upstream of the prop on an already bonded shaft? Do I need to ensure I put another at the end of the prop shaft somehow?
4. I've pulled a few engine zincs and find I have teflon tape on the threads. Is that not self-defeating?
4a - Corollary to previous - my "on land/dirtbike" skills have me as an aggressive user of loctite (non-perm) on ANYthing that vibrates and NeverSieze on dissimilar metals I to want to later remove without needing a cutting torch. I've had to re-examine these habits shipboard and find more thought is required on every single fastener. I've discovered Tefgel as something that has its place (e.g. steel bolts holding my aluminum windlass cover down). Does Loctite have a role in vibration mitigation? Is there a marine substitute I should use instead? Ditto for NeverSieze, though, my (low certainty) reasoning tells me I'll make things worse using it via electrolysis. I REALLY want to use it on the shafts that my raw water impellers mount on but I'm hesitant that some failure mode I should have seen is just waiting to screw me up good.
5. I discovered during the winterization that the basket in my AC raw water strainer is eaten a smile into itself on the very bottom. I am assuming electrolysis rot. My intent is to braze some SS perf over the hole (I have a friend's throw-away strainer)... it's sort of like the NeverSeize thing... am I creating an electrolysis vulnerability by adding brass?
6. Adding a galvanic isolator.. I'm convinced of the goodness. Can someone recommend a physical location in an NT42 to effectively mount one?
Again... apologies if multi-topic posts are looked down upon. Any contribution to enlightening me on any of the points above would be sincerely appreciated.
Gilhooley
I'm in my second year of ownership but really just my first one not farming 100% of the work out. Attempting to think for myself and understand what "the right way" is vs "the way everyone tells you to do it" and ensuring I'm on the right part of that fork. I've been working all these points myself for some time and have come to obstacles to moving forward for most of these. Certainly there is information "out there" on all of this but the vast majority is lacking any connection to specific cause/effect motivation. Hopefully it's not a mortal sin to collect a number of questions under a single post.
So... in no particular order. Breaking the following sections up so I can spread them over the appropriate sub-forums.
BOTTOM PAINT
1. I've got Micron CSC on my hull and except for 2 square inches, it's in good condition. I spoke with a gentleman at Interlux support who said I didn't need to sand it per se but merely to "rough it up". Is a palm sander overkill? I'm in that "used up" part of my life and machinery does make life better. If not a sander (I'm rich in 80 grit pads btw), then what might you suggest?
2. Order of operations - zincs and paint. I see advantages to doing it both ways but will probably put the zincs on first and delicately cut in around them as I paint... is this anti-stupid?
3. Paint interaction with bonding system - a paint with copper in it sounds as though it has the potential to interact with the bonding system. Any considerations here?
4. While I've been warned away by friends from doing this because of "looks", I'm thinking of doing two coats over the dark blue paint on there now. First a red layer (1 gal) with deployment priority to the high-wear areas, going as far as the gallon will go. Then using applying dark blue (sounds like 1.5 will handle completion). The idea being to have an obviousness when paint wear has moved to an actionable level. I'm sure I'm not the only one that has thought of this but then.. my idea for the V8/6/4/2 engine was later proven to suck to the moon by Cadillac saving me considerable personal embarrassment from my high school mates. So... anti-stupid or am I missing some basic fact and should just do it all one color like everyone else?
ELECTROLOSYS, BONDING AND GROUNDS
As I'm trained in electrical engineering, I find the myriad of things that can screw you royally under this subject fascinating... how the sets of best practices for the various domains (shore, boat AC, boat DC, bonding, signaling, etc) must all coexist sans significant pathologies.
1. They say "check the bonding system before you paint". Is there some particular pathology that drives this point? Check the totality for perfect functionality? I've been searching for a system check procedure that I can accept (i.e. a cause/effect connection to specific faults I want to discover and correct) but mostly all I find is hand waving that falls into the "the way everyone tells you to do it" bucket. Suggestions/pointers deeply appreciated.
2. If I understand a basic principle for mitigating vulnerability to electrolysis, it is that if one can isolate a metal in contact with sea water that that is preferable to bonding it and expanding the number of places a failure can occur. So... my skeg and rudder appear to be isolated from anything else in my boat (assuming hydraulic fluid is a poor conductor). Why would they bond it? Why would they put zincs on it? It isn't connected, or at least seemingly so.
3. There's a brush in the engine room bonding my prop shaft. There's not quite 1.5" of shaft between my prop and where it enters the boat. I can turn a little bit of a 1.5" zinc off on my lathe and make it fit. Do you see any problems with adding a zinc upstream of the prop on an already bonded shaft? Do I need to ensure I put another at the end of the prop shaft somehow?
4. I've pulled a few engine zincs and find I have teflon tape on the threads. Is that not self-defeating?
4a - Corollary to previous - my "on land/dirtbike" skills have me as an aggressive user of loctite (non-perm) on ANYthing that vibrates and NeverSieze on dissimilar metals I to want to later remove without needing a cutting torch. I've had to re-examine these habits shipboard and find more thought is required on every single fastener. I've discovered Tefgel as something that has its place (e.g. steel bolts holding my aluminum windlass cover down). Does Loctite have a role in vibration mitigation? Is there a marine substitute I should use instead? Ditto for NeverSieze, though, my (low certainty) reasoning tells me I'll make things worse using it via electrolysis. I REALLY want to use it on the shafts that my raw water impellers mount on but I'm hesitant that some failure mode I should have seen is just waiting to screw me up good.
5. I discovered during the winterization that the basket in my AC raw water strainer is eaten a smile into itself on the very bottom. I am assuming electrolysis rot. My intent is to braze some SS perf over the hole (I have a friend's throw-away strainer)... it's sort of like the NeverSeize thing... am I creating an electrolysis vulnerability by adding brass?
6. Adding a galvanic isolator.. I'm convinced of the goodness. Can someone recommend a physical location in an NT42 to effectively mount one?
Again... apologies if multi-topic posts are looked down upon. Any contribution to enlightening me on any of the points above would be sincerely appreciated.
Gilhooley
....don't give up, just get a TF guru lobotomy... 
