How to bed fittings to aluminum spars
Scott
I just painted my aluminum spars and I need to replace all the stainless
hardware that I first removed. Should I coat the mated surfaces with
something to prevent corrosion due to the dissimilar metals?
No More Mr. Nice Guy!
Scott, I'm about to the same paint job. I was told to buy Tef Gel. It
prevents the galvanic corrosion that occurs between SS and alum.
Scott wrote in message <01bd67bb$35d5ef00$28c9c3d1@default>...
Anders Svensson
In this case I think the paint itself will help more than a little to
insulate. Tef Gel (or similar high pressure resistent coatings) will be
useful especially for self tapping screws and pop rivets.
There are also packing material available in specialist auto shops that
actually have some fastening propertys aside from insulating and sealing.
The idea is to hinder electric conductivity between aluminium and stainless
and keep moisture out from between surfaces. As you probably use Monel pop
rivets, you definitely do not want any flexible goo for insulation.
I mounted some stainless hardware wit the help of epoxy glue with filler on
my jib club boom, and after a some years, no visible corrosion is seen.
This was because there was slight mismatch between the radius of the boom
and some of the hardware.
-
Anders Svensson
----------------------------------------
No More Mr. Nice Guy! <can...@iu.net> skrev i inlägg
<itPY.88$qV1.6...@news1.atlantic.net>...
Mike Bennett
A rigger taught me this trick years ago...first, insulate the screws from
the Aluminum with one of the goops you can buy at the marine store.
Second, bring a plastic milk or water jug from home and cut it up to use
as a thin gasket between the stainless fitting and the Aluminum. You'll
never have a corrosion problem.
Enjoy.
Mike Bennett
Freeport 36 Stargazer
San Francisco
In article <01bd67e4$d1e08a80$LocalHost@zrkciqaa>, "Anders Svensson"
sailing vessel Manna
Scott wrote:
>
> I just painted my aluminum spars and I need to replace all the stainless
> hardware that I first removed. Should I coat the mated surfaces with
> something to prevent corrosion due to the dissimilar metals?
The one and only thing that will keep galvanitic corossion at bay is
using lanolin. West marine and I think BOAT U/S both carry it. It works
and is easy to use.
Andy
jktho...@earthlink.net
I would believe this trick of using a thin poly film - I've used black PVC
electrical tape slightly overlapping to provide the physical standoff insulation.
I don't think that lanolin would do it. They give it away almost in NZ, but it
has no tough permanent film strength.
Mike Bennett wrote:
Paul Kamen
Lanolin is also my goop of choice for attaching hardware to aluminum
masts.
--
fish...@netcom.com
http://www.well.com/~pk/fishmeal.html
-"Call me Fishmeal"-
Armond Perretta
>Paul Kamen wrote: ... Lanolin is also my ... choice for attaching hardware
to aluminum masts.
Off topic, but many riggers also recommend lanolin for lubricating
turnbuckles (bottlescrews for UK readers).
Good luck and good sailing.
s/v Kerry Deare of Barnegat
HWR Folk
sailing vessel Manna wrote:
>
> Scott wrote:
> >
> > I just painted my aluminum spars and I need to replace all the stainless
> > hardware that I first removed. Should I coat the mated surfaces with
> > something to prevent corrosion due to the dissimilar metals?
>
> using lanolin. West marine and I think BOAT U/S both carry it. It works
> and is easy to use.
>
> Andy
There are actually several ways to reduce corrosion between SS and
aluminium.
For fittings such as cleats, jammers, fairleads, etc. you may cover the
contact surface with plastic (electrical) tape. This prevents the metal
to metal contact that causes corrosion. Screws and bolts may be coated
with lanoline, but this may allow them to vibrate loose as the lanoline
provides thread lubrication. I have successfully used silicone sealant
on fasteners into alum. Acts as insulator and lock tight. In the late
'70s, working as a rigger in Calif. our shop used a graphite/silicon
paste on fasteners, can't remember name and haven't seen anything
similar since.
roman
Armond Perretta
>HWR Folk wrote: ... several ways to reduce corrosion between SS and
aluminium. For fittings such as cleats, jammers, fairleads, etc. you may
cover the contact surface with plastic (electrical) tape. ... I have
successfully used silicone sealant on fasteners into alum. Acts as insulator
and lock tight. In the late '70s, working as a rigger in Calif. our shop
used a graphite/silicon paste on fasteners, can't remember name ...
I have not tried the sealant or pastes Mr. Folk mentions, but we do use the
"electrical tape" method and think it is good practice. Additionally we
coat all SS fasteners with a paste form of zinc chromate (in a tube), and
also paint all relevant surfaces with zinc chromate paint (available in
small cans). Still it seems that regardless of the method chosen, some
corrosion is inevitable.
I was hardening up the 150 genoa luff on a friend's Tartan 34 one summer
afternoon as we beat up the Toms River in NJ. We had re-mounted the winch
on the mast the previous April using "sound" methods. The winch pulled
loose from the mast and flew upwards at great speed, missing my nose by
about 2 inches. I don't have a classic profile, but I would still hate to
change something so familiar.
Leonard Stanton
Scott wrote:
> I just painted my aluminum spars and I need to replace all the stainless
> hardware that I first removed. Should I coat the mated surfaces with
> something to prevent corrosion due to the dissimilar metals?
Keeping the water out of faying surfaces is all important. This is based on
spending the last few months
stripping professionally applied awlgrip from my mast. There was complete
coating failure under every
fitting after just five or six years. When cleats etc. were removed the
paint came off in chunks with lots of
aluminum oxide. The only areas without corrosion were under the rigid boom
vang fitting. These had been
installed three years earlier with lots of silicon.
The only way to stop corrosion is to keep water out of the joint. This is
the job of bedding compounds.
The type isn't too important.. Electrical isolation can be improved by some
sort of barrier between
the aluminum and whatever is being attached. Formica works well under
winches.
The general consensus around the mast dock was to coat all fastenings with
Lanicote to prevent seizing.
Remember, free advice is often worth what you paid.
Leonard Stanton
jktho...@earthlink.net
This is a good reason to not have deck mounted winches - Imagine you're hunched
over a winch, straddling the line, and it rips off the deck, between your legs,
above your knees, ....... , I would hate to change something so familiar.
Paul Kamen
jktho...@earthlink.net writes:
>This is a good reason to not have deck mounted winches...
Except that deck-mounted winches don't seem to break loose. And even if
they do, the deck-mounted winch will fly horizontally a short distance to
the turning block and then run out of steam. The mast-mounted winch tries
to go into orbit...
Charlie Mayne
jktho...@earthlink.net writes:
>This is a good reason to not have deck mounted winches - Imagine you're hunched
>over a winch, straddling the line, and it rips off the deck, between your legs,
>above your knees, ....... , I would hate to change something so familiar.
Standard practice: avoid standing between the winch and the load, inside the
angle of a line into and out of a deck cheek block, etc.
Best regards,
Charlie
CS30 "Sprite"
--
Charlie Mayne | Motorola Incorporated
char...@pets.sps.mot.com | Microprocessor Products Group
| Austin, Texas 78735-8598
"I am concerned about my memory. But, for the life of me, I can't recall why."
jktho...@earthlink.net
Actually what I wrote was - This is a good reason to not have deck mounted
winches - Imagine you're hunched over a winch, straddling the line, and it
rips off the deck, between your legs,
above your knees, ....... , I would hate to change something so familiar.
You've lost something in the retelling.
Paul Kamen wrote:
jktho...@earthlink.net
That's the piece I wouldn't want to be missing - the area of the "CHEEK" block -
hint, hint.
Or as Monty Python said - "Nudge, nudge, wink, wink, you know what I mean ??
Or as my grandmother used to say - "A wink's as good as a nod to a blind man".
Charlie Mayne wrote:
> jktho...@earthlink.net writes:
>
> >This is a good reason to not have deck mounted winches - Imagine you're hunched
> >over a winch, straddling the line, and it rips off the deck, between your legs,
> >above your knees, ....... , I would hate to change something so familiar.
>
Rodney Myrvaagnes
On Wed, 15 Apr 1998 10:46:02 -0700, jktho...@earthlink.net wrote:
>This is a good reason to not have deck mounted winches - Imagine you're hunched
>over a winch, straddling the line, and it rips off the deck, between your legs,
>above your knees, ....... , I would hate to change something so familiar.
>
That is only a good reason not to straddle the line, not to avoid
deck-mouinted winches. Where else would you put them?
Graham
Paul Kamen wrote in message ...
> jktho...@earthlink.net writes:
>
> >This is a good reason to not have deck mounted winches...
>
>Except that deck-mounted winches don't seem to break loose.
Agreed
>And even if they do, the deck-mounted winch will fly horizontally a short
distance to
>the turning block and then run out of steam. The mast-mounted winch tries
>to go into orbit...
I have some problem with the physics here - The mastmounted winches would go
further despite having to overcome gravity??
Graham
Armond Perretta
>Rodney Myrvaagnes wrote: ... [dangers of lines under tension] ..a good
reason not to straddle the line, not to avoid deck-mouinted winches. Where
else would you put them?
Judging from the title, the original question concerned mounting winches on
an aluminum mast. That is one answer to Rodney's question.
Let us assume that in both cases (mast mounted and deck mounted winches),
the total number of winches remains constant (for example, with multiple
rope clutches or the like). Then aside from lowering the center of mass
slightly, what are other advantages of deck mounted winches on a cruising
sailboat? For comparison, some disadvantages to the cruising sailor may be:
-additional holes in the boat (instead of the mast)
-additional possible leaks in the boat
-additional hardware (at minimum a turning block for each halyard or
lift, assuming the number of cleats or stoppers remains the same)
-additional expense (hardware and hardware fasteners, backing plates
for the winches)
-additional items to trip over in the dark
-loss of real estate (cruising sailors like to lounge)
On a racing sailboat one can ignore one or more of these issues for the sake
of winning. I wonder how many cruising sailors are willing to ignore them.
jktho...@earthlink.net
Sorry for the confusion - I was worried about the medics. Personal property,
etc.
Joe Kovacs
In <01bd67bb$35d5ef00$28c9c3d1@default>, "Scott" <swybr...@chesco.com> writes:
>I just painted my aluminum spars and I need to replace all the stainless
>hardware that I first removed. Should I coat the mated surfaces with
>something to prevent corrosion due to the dissimilar metals?
For corrosion, mere coating on the mated surfaces won't help
here. Lanolin's worthless. Electrical tape might help, but I
doubt it because it's not strong enough in the right way.
You have to electrically insulate the stainless steel parts from
the aluminum, however you want to do that.
So you put a strong thin nylon plastic pad under the fitting, put
nylon bushings on the SS bolts where they go through the
aluminum, and nylon washers under the nuts inside the mast.
Nylon corrosion washers are available for that service, but I
don't know where. And if you want to use something other
than nylon that's just as strong, feel free.
The SS parts can touch each other, but the SS cannot touch
the aluminum. Test the installation with a little Radio Shack
volt/ohm meter or something.
If you're going to attach the fittings with SS screws biting
into the aluminum there's inherently no way to insulate, to
prevent glavanic corrosion.
But you see, everything's a compromise. How did the
manufacturer do it, and is it holding up OK? and maybe just do
the same thing if it is?
Joe Kovacs
Guelph Ontario Canada
No More Mr. Nice Guy!
Joe, All the riggers I know use Tef-Gel which is an anticorrosion product
that is supposed to last a very long time. They swear by it and tell me they
have removed SS screws ten years later witout problems. It prevents galvanic
corrosion apparently.
Joe Kovacs wrote in message ...
Graham
Joe Kovacs wrote in message ...
>In <01bd67bb$35d5ef00$28c9c3d1@default>, "Scott" <swybr...@chesco.com>
writes:
>
>>I just painted my aluminum spars and I need to replace all the stainless
>>hardware that I first removed. Should I coat the mated surfaces with
>>something to prevent corrosion due to the dissimilar metals?
>
>For corrosion, mere coating on the mated surfaces won't help
>here. Lanolin's worthless. Electrical tape might help, but I
>doubt it because it's not strong enough in the right way.
>
>You have to electrically insulate the stainless steel parts from
>the aluminum, however you want to do that.
>
Section cut
We usually use Monel (Copper-Nickel alloy) for the rivets on masts - this is
accepted as good practice - I have not studied the theory behind it.
However, if it works for rivets, then it will likely work for bolting too -
So why not use Monel bolts for S/S on Aluminum.
When attaching a winch, there is a different problem - The base of the winch
is bronze, the bolts are often S/S and the mast aluminum - I have seen S/S
bolts corrode and shear off in this application (However, many boats were
built this way - at least in the Great Lakes area)
I would like to obtain a good answer on this and may just contact some of
the mast builders for guidance. (We do not tend to have a problem in fresh
water)
Applications - S/S parts on Aluminum masts (For example spreader bases,
external track)
- Bronze parts on Aluminum masts (For example
winches)
- Aluminum parts on Aluminum mast (For example cleats)
Graham
Windjammer Sails, Box 23004 Amherstview PO Kingston Ont.
Canada K0H 1G0. (613) 389-4349 FAX (613) 389-4762
"Everything for sailing - At a good price!"
MAIL WEB SITE
wind...@fox.nstn.ca http://fox.nstn.ca/~windjamm/
Joe Kovacs
In <353a2...@news.cgocable.net>, "Graham" <wind...@cgocable.net> writes:
>
>Joe Kovacs wrote in message ...
>>In <01bd67bb$35d5ef00$28c9c3d1@default>, "Scott" <swybr...@chesco.com>
>writes:
>(We do not tend to have a problem in fresh
>water)
That's a major factor, in your favour.
Joe Kovacs
>Joe, All the riggers I know use Tef-Gel which is an anticorrosion product
>that is supposed to last a very long time. They swear by it and tell me they
>have removed SS screws ten years later witout problems. It prevents galvanic
>corrosion apparently.
>Joe Kovacs wrote in message ...
>>In <01bd67bb$35d5ef00$28c9c3d1@default>, "Scott" <swybr...@chesco.com>
>writes:
>>
>>>I just painted my aluminum spars and I need to replace all the stainless
>>>hardware that I first removed. Should I coat the mated surfaces with
>>>something to prevent corrosion due to the dissimilar metals?
>>But you see, everything's a compromise. How did the
>>manufacturer do it, and is it holding up OK? and maybe just do
>>the same thing if it is?
O good. We're going to get into how the Technicians do it. I've
wanted to post about how the automobile Technicians do in
Rochester NY for a long time. We'll start with the guy in the shop
across from the Water Works fifteen years ago. He replaced the
failed wheel bearing on the passenger's side of my VW camper.
Then he took apart the wheel on the driver's side and threw
Orange Automotive Shop Dirt on that bearing so it failed a month
later. Then he went after his wife with an axe. Twice.
Joe Kovacs
In <W7q_.483$qV1.3...@news1.atlantic.net>, "No More Mr. Nice Guy!" <can...@iu.net> writes:
>Joe, All the riggers I know use Tef-Gel which is an anticorrosion product
>that is supposed to last a very long time. They swear by it and tell me they
>have removed SS screws ten years later witout problems. It prevents galvanic
>corrosion apparently.
If there's no corrosion, it's for other reasons. Tef-Gel sounds like
teflon particles in a petroleum or goopy matrix. There's no value
to the teflon there. The matrix is like a caulking compound.
When it's new, in place and sealing well, water will run off and
dry quickly from around the outside of the fitting. With the
slightest crack or delamination, water (the electrolyte<==uh oh!)
will get in, stay and the aluminum goes.
I say get them to tell you about the ones that failed ,too,
especially the ones beyond Fiji.
There are several factors in aluminum/SS corrosion. If the
structure hasn't coroded in fifteen years and you're going
to stay in the same fresh water for the next fifteen, put
it back the way it was, of course. And then you can put
Tef-Gel on it and it'll prevent galvanic corrosion.