Best Rust/Painting Strategy

Professional Mariner Forum
#28

When I started shipping twenty years ago the company I was with would simply paint rust. There’s always a chip or spot that appears and it would quickly be covered with paint. No prep, no needle gun or grinding. Just paint. There was almost no rust anywhere. Certainly no rust that lasts. It might have been one guy’s job to walk around with a paint can and brush once a week for a few hours.

Now I’m at MSC and they spend hundreds of man hours a week needle gunning and grinding with all sorts of preps and primers yet most MSC ships looks like turd stained rust cancers. I’ve tried to convince folks that weekly spot painting over new/small rust spots would save a lot of time and money but everyone here thinks I’m insane.

I’m now convinced that painting over small rust areas is vital preventative maintenance. It’s like greasing fittings. A few man hours a week greasing fittings prevents a lot of labor restoring and rebuilding a frozen block or roller later.

First give the area a quick fresh water rinse in the morning followed by spot painting in the afternoon. If after a while the area looks spotted go ahead and paint the whole area with topcoat. Do not grind off the old paint that had protected the metal all those years.

Once the rust on the whole ship is under control then repair any blistered areas. But keep up on the spot painting.

#29

I know to most what you are saying is heresy but there is some truth to it. Rust needs moisture and air. If you paint over the first part you see you at least cut off the oxygen to that spot. Unless you can wire brush, prime , paint and give each layer time to cure properly according to the paint manufacturers recommendation you are doomed to failure on a large area. With a ship at sea it is practically impossible to follow manufacturers recommendations which include the environmental conditions. So, I agree with your approach. Cut off the air to the first sign of cancer until such time as you can get in a position to handle the problem properly. The AB’s can better spend their time doing other things. Geez…how many times have I walked past some needle gunning OS or AB only to not be able to properly dog a hatch because the bushings were worn out or not lubricated?

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#30

Years ago a want ad for painters in the Seattle area specifically stated “NO SAILORS!”
:laughing:

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#31

What happened to dogs and Irishmen?

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#32

It’s like first aid:

  1. Stop the bleeding by applying pressure (put a spot of paint over the rust until the rust stops).

  2. When the bleeding stops set broken bones and stitch the wounds (take a grinder or needle gun to any bubbles of rust).

  3. Once the wounds are repaired cosmetic surgery may be used (paint over the area to make the area match or cut in sharp lines).

Now look at the photo below. This area was painted about two months ago. A tiny bubble of rust has begun. The time to address this is NOW (or a month ago) with a little spot of primer and then a little spot of topcoat. It would take two minutes. I’d bet if that were done soon the area would be nice a year from now.

Except they won’t paint that rust spot and a year from now it’ll be another turd stain rust cancer just like the thousand other turd stain rust cancers all over this ship. That’ll take a few days to fix then not to mention the loss of a little more steel.

image

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#33

When applied properly and allowed to cure fully, Enrust holds up pretty well and is very adhesive. If you have the equipment and opportunity to white blast and properly apply a complete system, more power to you, but you’re probably not underway. In my experience most problems with Enrust are the product of impatience and poor quality control. It adheres just fine as anyone who has ever gotten any on their hands or clothing can attest. It may not be a permanent system but it can certainly help in getting and keeping shipboard rust under control under realistic non-shipyard conditions.

#34

I found that using less paint and more coats held up longer than any other process. Wait a good day after applying rust inhibitor Thoroughly agitate your paint feather your edges, apply two VERY light coats of primer followed by at least two light coats of interthane

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#35

In the way-back machine, I had the best result with ospho after getting the rust gone. Preferred wire-wheel unless they were bustin’ scale rust. Washed with fresh water, then 2 coats of primer, then 2 top coats. I made a bet with the bos’n over the fresh-water part. He said the water didn’t matter. We painted to identical parts of the deck - same exposure to crap. He agreed, water made the difference.

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#36

Wouldn’t it be best to quickly hit that tiny area with the edge of a wire wheel and get the rust out, then prime it and paint it? Add 5 minutes to the job (including getting the wire wheel and extension cord) and should prevent future rust scale.

(That spot was probably the result of an imperfect top coat.)

#37

The first thing to look at is the Enrust application and making sure you’re following the directions precisely. Two coats 20-30 minutes apart then 24 hours cure time before overcoating.

Next, make sure you’re using enough coats of primer and paint. Rolling on will likely require twice the recommended coats of each because you can’t roll on as think as you can spray on, minimum of two coats of each and maybe three of top coat. Make absolutely sure the the top coats have no holes in them to allow moisture in, frequently two contrasting colors are recommended so you put the first coat in one color, making sure you can’t see any primer through that, then put the final coat in another color, making sure you can’t see any of the previous coat through little holes.

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#38

the last rig I worked on was made from such poor steel it had already had the decks grit blasted and new paint scheme within 3 years I was on for years 4-5 and it was happening again.
The rust was coming from inside the plate.
It was meant to last 10 years, crew didnt think so

IMHO needle gun will trap contaminants into the surface so its never really clean

#39

Yeah, rig builders used to buy the cheapest crap they could find to build a rig. Rig buyers were happy, they knew what was going on. Drillships and MODUs are disposable by design and the buyers know that when they sign the build contract. Low bidder gets the contract, minimum specs for steel, valves etc… Just enough to get out of the yard. Then they pay out the wazoo for drilling equipment but expect it all to be maintained by a minimal crew and do UWILD instead of shipyard. Been like that for years.

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#40

The best strategy is to be on a vessel not painted with International paint.

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#41

works when on Megayachts…

#42

Its been a while but your absolutely correct, fresh water wash down after ospho allot of bosns dont know this or ignore it. Regardless its written in the application instructions.

#43

Companies spend a lot of money on paint and coating systems unfortunately much of that money is wasted during application by ship’s crew. I have found very few Chief Mates and fewer bosuns knew the application specs of the paint they had or followed them if the specs were in hand.
When I was on the Far East run the window of opportunity was from Hawaii to Guam and from there perhaps as far as Kaohsiung. The weather was generally good to do the work and surfaces could be reasonably prepped. On the way back to the States where it was cold, wet and the weather crappy it was a total waste of time and money. I once told the Mate he would be ahead of the game if he just mixed the paint, let it set up and throw the bucket over the side for all the good he was doing (with spray coming over the deck). Trying to make the ship “look good” for the office coming back across the north Pacific just made the situation worse.
When power tooling, wire wheels should NOT be used, grinding and sanding wheels should. Grinding/sanding wheels or discs give a good surface profile for the paint to adhere. Wire wheels polish the steel resulting in an extremely poor surface profile. The result is akin to painting glass. Oil, grease, salt and other contaminates must be removed. The surface must be dry.

See section 4. https://ww2.eagle.org/content/dam/eagle/rules-and-guides/current/survey_and_inspection/49_application_inspection_marine_coating_systems_2017/Coatings_GN_e-Jan17.pdf

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#44

Has anyone seen the ad’s for Dustless Blasting machines on the Motor Trend Channel? I always thought that would be a slick system for fabric maintenance.

#45

Has anyone had a difference with anti corrosive pigments in the paint? For example Interprime 198 vs 234.

#46

I believe (but not sure) Interprime 234 uses a zinc compound as the “anti corrosive” pigment. This helps create a metallic film that acts as a physical barrier, as well as providing cathodic protection for the underlying steel. Note that it is not sold as a “Zinc Rich” primer. The type of primer that should be used is dependent on the top coat going over it.

Paint should be viewed as a system and not individual components. The recommended top coats are not the same for Interprime 198 and 234.

#47

There was an ad in the local Virginian Pilot over 30 years ago for painters. Caught my eye “Sailors need not apply”. There were also signs downtown Norfolk well prior to that “Sailors and dogs keep off the grass”. Agreed somewhat on the painter thing, but not so much on the other. They liked our money, but didn’t like us. I don’t spend much money in that town.