Bottom paint for prop and shaft?
Lynne Saner
barnacles. This year, I want to prevent any growth and thought about
covering the prop, and shaft, with bottom paint. Any thoughts on this?
Stephen
sa...@javanet.com
Jeff Thompson
Each time we've hauled, we've tried the latest "cure" - old black oil
from diesel engines well rubbed in, lanolin, STP, hard bottom paint,
regular bottom paint, ... no matter what it is it's all gone in a few
hours of revolving. If you're just sitting at the marina, paint it.
Bill Harrison
You DON'T want to paint your Stainless steel shaft. If you can get paint
to stick on, you create an anerobic condition, and can get pitting of the
shaft.
I have primed, painted, epoxied, roghened and done everything to the prop,
paint will never stick, This is because you get implosion of water at the
tips of the propeller when water cavitates (equalizes pressure at the end
of the prop.).
Believe it or not, I cleaned the prop and put STP on the thing, and I had
the best year of barnacle freedom. I went under at the height of the
season, and scraped the few that were on. The guy on the next boat used
desitin, wth similar results. If you DON'T get some barnacle action on
the prop, you may be having an electroysis problem as the barnacles don't
like the stray current.
Another thing some people do around here. If they don't use the boat for
a couple of weeks, they run the engine in gear at the dock to spin the
little critters befdore they mature.
Bill
Bob Richardson
>
>When I hauled out last fall, my brass prop was covered with small
>barnacles. This year, I want to prevent any growth and thought about
>covering the prop, and shaft, with bottom paint. Any thoughts on this?
I've used lanolin with some success. Although it's not perfect, it seems to
help a bit. Heat the prop in warm to hot water first, then rub on the
lanolin. Lanolin is sold in N.Z. for this purpose.
Jeff Thompson
I bought it in NZ for that purpose - I didn't think it had any noticable
effect. Makes your hands soft from fooling around with it though.
I do use it for inside the boat metal coating - works great there on
cast iron pillow block bearings on the prop shaft, the windlass motor
and casing, etc. It forms a thick, gummy, dried out surface that
petroleum grease doesn't so it doesn't smear off every time you get near
it.
mark edward balcom
>Lynne Saner wrote:
>>
>> When I hauled out last fall, my brass prop was covered with small
>> barnacles. This year, I want to prevent any growth and thought about
>> covering the prop, and shaft, with bottom paint. Any thoughts on this?
>>
Brass falls apart in salt water. Ok, now to the point. There is a new
theory that a bronze prop will allow marine growth if the system is "over
zinked". It suggests that by reversing the nomal current flow critters
can grow on the bronze surface that would not otherwise. Bronze should be
anti-fouling. You might take a look at how much zink you are using and if
in fact it is needed at all. A bronze prop on a monel shaft with a
vibration absorbing rubber coupling to the engine for instance should not
need zink.
Just a thought.
Mark S/V Kaiulani
shs...@li.net
In Article<317E62...@javanet.com>, <sa...@javanet.com> write:
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> From: Lynne Saner <sa...@javanet.com>
> Newsgroups: rec.boats,rec.boats.cruising,rec.boats.building
> Subject: Bottom paint for prop and shaft?
> Date: Wed, 24 Apr 1996 12:19:06 -0500
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> When I hauled out last fall, my brass prop was covered with small
> barnacles. This year, I want to prevent any growth and thought about
> covering the prop, and shaft, with bottom paint. Any thoughts on this?
>
> Stephen
> sa...@javanet.com
Stephen - For about 20 years, I have been just coating the prop with parafin
wax. I warm the prop with a heat gun (used to use a bernzo-matic torch, but
the yard started getting kinda' excited about that!) until a block of parafin
wax just barely melts onto the blade surface. I coat the blades and hub this
way, then go back over it with the heat gun to even out and "flow" the wax.
It is still on the prop at the end of the season and I have never had one
barnacle on the prop since using this method. I get them on the rudder and
on other places, so I know they're around, but not on the prop. We keep the
boat in Long Island's substitute for water for about 8 months and do maybe 20
to 30 hours of motoring in between sailing in that time. You can get the
parafin in blocks at hardware or craft stores.
I tried painting the prop once and it washed off after a few hours of running
time, and then the prop always had barnacles for the rest of that year.
I also got a real bumper crop in spite of the parafin one year when I put a
zinc collar on the shaft. (I didn't have an electrolysis problem, I was just
"making sure".) I don't know whether barnacles like the taste of zinc,
whether it sets up an electric field that attracts them, maybe its just magic,
but next year I didn't use the zinc and went back to no barnacles.
Hope this works for you as well as it does for me.
Frank Fitz... and the crew of the mighty Draco.
shs...@li.net
P.S. Somewhat ashamed to admit I originally got this idea from an old
stink-potter!
MardiC
Mark wrote:
> I hope that the prop is not actually brass. It should be a bronze alloy.
> Brass falls apart in salt water.
Wheels are normally either stainless or brass. With brass wheels, anodic
protection is very important. When a brass wheel is attacked by galvanic
action,(or electrolytic action) it loses its zinc which weakens the
wheel. That wheels are made of brass (copper alloyed with zinc
primarily) can be verified by contacting anyone who *manufactures* them.
The only time brass is not recommended in a marine environment,
especially under water, is where it cannot be anodically protected. So no
brass fasteners, etc! BTW, stainless wheels are much superior...but one
gets what one pays for.
Mark Ray
I know other people has good success with the NZ lan. and the one i saw
work was called sheep shit. You will not have much success with anitfoul
as it will not stick on for long. There was a product from sweeden in
airsol form that had some success if you could get it to stick. the mill
scale in the metel was the problem with the adheasion. you just have to
dive and clean the thing to keep it free of growth. What you spend on
products could go towards good mask and fins.
mark
mark edward balcom
>
>I also got a real bumper crop in spite of the parafin one year when I put a
>zinc collar on the shaft.
If the system is "over zinked", that is if there is enough zink to
reverse the current flow, rather than just cancel it, then the natural
resistance to marine life that the bronze presents will be neutralized
and critters will grow on the prop. If the drive shaft is compatible with
the prop no zink should be used. If the drive shaft. prop and other
underwater metal are electrically bonded together then enough zink should
be used to protect the least nobel metal in the system and no more. As I
understand it this can be a little tricky to figure out. My system is
fairly simple in that the prop and shaft do not connect to any other
metal
Mark S/V Kaiulani
Steve Weingart
In article <4m1qqi$f...@raffles.technet.sg>,
After a discussion last year on this subject, I just started an experiment.
I've used standard and spray-on outdrive paints in the past with little or no
success.
One suggestion was to clean the prop, then gently heat it with a propane torch
until paraffin would melt on it, then rub it all over with the paraffin. This
would supposedly fill the surface microscopically with paraffin to prevent
growth.
I did it and the boat has been in three weeks, no growth yet;-)
I'll report as the summer wears on (paints lasted about three months here in
FL).
Steve
Mark Anderson
In article <31828A...@aol.com>, MardiC <mar...@aol.com> wrote:
>
> Wheels are normally either stainless or brass. With brass wheels, anodic
> protection is very important. When a brass wheel is attacked by galvanic
> action,(or electrolytic action) it loses its zinc which weakens the
> wheel. That wheels are made of brass (copper alloyed with zinc
> primarily) can be verified by contacting anyone who *manufactures* them.
I thought the yellow metal props/wheels were phosphor bronze.
And BTW, why not use a bronze shaft also and skip the anodic protection,
just insulate the shaft and prop at the engine coupling. Bronze shafts
certainly have been used in the past. Why the dominance of stainless
now? Is it that necessary to be harder due to packing gland wear. In any
event, I intend to use a dripless type gland. They don't wear on the
shaft.
--
Mark
"The trouble with good ideas is that they soon degenerate into a lot of hard work."
Steve Weingart
In article <andermar-050...@ip-pdx11-32.teleport.com>,
ande...@teleport.com (Mark Anderson) wrote:
>In article <31828A...@aol.com>, MardiC <mar...@aol.com> wrote:
>>
>> Wheels are normally either stainless or brass. With brass wheels,
anodic
>> protection is very important. When a brass wheel is attacked by
galvanic
>> action,(or electrolytic action) it loses its zinc which weakens the
>> wheel. That wheels are made of brass (copper alloyed with zinc
>> primarily) can be verified by contacting anyone who *manufactures*
them.
>
>I thought the yellow metal props/wheels were phosphor bronze.
As far as I know, you are correct, brass should not be used in any
structural part in a saltwater boat.
>
> And BTW, why not use a bronze shaft also and skip the anodic
protection,
>just insulate the shaft and prop at the engine coupling.
You would probably not have to insulate, since the coupling is
presumably in a dry location, there would be minimal corrosion,
>Bronze shafts
>certainly have been used in the past. Why the dominance of stainless
>now? Is it that necessary to be harder due to packing gland wear. In
any
>event, I intend to use a dripless type gland. They don't wear on the
>shaft.
Many bronzes and stainless steels are *very* close from a galvanic
standpoint. A half pound zinc propnut cap lasts me a year and the prop
and shaft are fine.
Stainless is just stronger and more durable, I couldn't see going to a
bronze shaft when a stainless shaft is stronger and for the same size,
that includes bending & such, not just stuffing box wear.
>
Steve
Jim Robinson
Jeff Thompson <jktho...@earthlink.com> wrote:
>Lynne Saner wrote:
>>
>> When I hauled out last fall, my brass prop was covered with small
>> covering the prop, and shaft, with bottom paint. Any thoughts on this?
>>
>> Stephen
>> sa...@javanet.com
>
>from diesel engines well rubbed in, lanolin, STP, hard bottom paint,
>regular bottom paint, ... no matter what it is it's all gone in a few
>hours of revolving. If you're just sitting at the marina, paint it.
I also had this problem for years on a twin engine inboard
power boat. Props, struts, strainers, rudders (all bronze)
and stainless steel shafts and trim tabs collected
barnacles by mid season. Last year I did the following,
and it worked. Virtually no barnacles!!
Sand or otherwise prepare all below waterline metal parts.
Prime with one coat of PETIT "METAL PREP Quick Dry Zinc
Chromate Primer 6462." It cost $15 per quart, but I
stillhave enough left for the third preparation. Then
paint with your normal bottom paint - one or two coats,
being careful not to drip or run. I still had bottom paint
on the props and shafts at the end of the season. Without
the primer, the plain bottom paint will come off within
several weeks. This was recommended to me by E&B Marine,
one of the local boating equipment stores in the
Washington, D.C. area. Good Luck!
Jim Robinson
Jeff Thompson <jktho...@earthlink.com> wrote:
>Lynne Saner wrote:
>>
>> When I hauled out last fall, my brass prop was covered with small
>> barnacles. This year, I want to prevent any growth and thought about
>> covering the prop, and shaft, with bottom paint. Any thoughts on this?
>>
>> Stephen
>> sa...@javanet.com
>
>Each time we've hauled, we've tried the latest "cure" - old black oil
>from diesel engines well rubbed in, lanolin, STP, hard bottom paint,
>regular bottom paint, ... no matter what it is it's all gone in a few
>hours of revolving. If you're just sitting at the marina, paint it.
Prime all underwater metal gear (bronze,stainlesss steel,
can't vouch for aluminum) with PETIT "METAL PREP Quick Dry
Zinc Chromate PRimer 6462." Then paint with your normal
bottom paint. With the primer, the bottom paint will stay
on props, shafts, rudders, struts, trim tabs, etc. Without
it, the paint sluffs off within a few weeks. Good luck!
Jim Robinson
Jeff Thompson <jktho...@earthlink.com> wrote:
>Lynne Saner wrote:
>>
>> When I hauled out last fall, my brass prop was covered with small
>> barnacles. This year, I want to prevent any growth and thought about
>> covering the prop, and shaft, with bottom paint. Any thoughts on this?
>>
>> Stephen
>> sa...@javanet.com
>
>Each time we've hauled, we've tried the latest "cure" - old black oil
>from diesel engines well rubbed in, lanolin, STP, hard bottom paint,
>regular bottom paint, ... no matter what it is it's all gone in a few
>hours of revolving. If you're just sitting at the marina, paint it.