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steel boat corrosion protection advice?

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hi all.... im new to this forum and new to coating bare steel.

ive a steel barge 20m long to which I have partial access to the base plate.

I was thinking about making a mix of blo and beeswax with some sort of thinners to rub on the area of rust free base plate I have access to.

I want to slow/stop any corrosion 

any ideas on this? 

smell would be a concern ... I would rather not use something that will smell for months as we live above!

also I was wandering if anyone has any ideas as to something that could be poured in to the rest of the hard to access parts of the bilge?

just to prevent rust.

the old dutch barges had like a oil/fat rubbed on from new and it still protects the ones ive seen to this day where intact..

I need to use a liquid type mixture as it needs to move around the nooks and crannies 

all ideas are welcomed and thanks in advance.



afloat on a river somewhere [ I do have an anvil] ;-)

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Welcome aboard from 7500' in SE Wyoming.  Glad to have you.

I'm assuming that you are talking about the interior of the barge, not the outside which is in contact with the river/other water.  Correct?

Is the metal to be coated clean or is there rust and junk on it?

Is the "base plate" the bottom of the barge with air on one side and watr on the other?

How much headroom and ventilation is there in the spaces you want to apply the coating?

Even with these questions answered I'm not sure I'll have a suggestion but someone else may have.  It is a little out there for a blacksmithing forum but there may be someone with a pertinent suggestion.

"By hammer and hand all arts do stand."

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hi George and thanks for your welcome... yes the interior of a boat it is and yes water below and air above ..... 

the metal to be coated is  pretty clean in the exposed area I have scraped it back to clean steel and each year tried a different approach....owatrol oil amongst others.

im tired with painting as in winter a little condensation can build in this area due to the main log burner heating the main cabin so warm I guess...

there is just enough room to crawl in but not stand up 

I was hoping for a wipe with some type of oil/ oil mix and leave solution!

I have a carbon filter extraction fan with which to suck out and filter the air in this area .

thanks again and hi from the uk :-)


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You want to rust proof the interior of the barge hull, not the outside. Yes? 

I'm thinking you need to put it on blocks out of the water, sand blast it and use a high tech coating. There are a number of rust inhibiting, acid etch 2 part, epoxy primers and  2 part epoxy finish paints. It's a serious process but 2 part epoxy paints cure quickly so the fumes go away in a couple days.

Another potential after sandblasting type prep. is to use a rust inhibiting automotive undercoating or bed liner. Were it me I'd use a bed liner, Rhino Line is available world wide and literally bullet proof. Seriously American light and medium military vehicles have been getting undercoated and the inside of doors and panels Rhino lined for years now and damage from bullets and IEDs has gone WAY down.

Here's where it gets tricky, it would be simple if you were painting the outside but more complicated on the inside, it's the same principle though. We have a LOT of float planes here, frankly more than any other kind of private plane. Keeping water out of the floats (pontoons) is always a problem, a float baling pump is a regular piece of gear carried. But there is a really effective trick for filling all the gaps no matter how small when painting.

You put a vacuum cleaner hose in the baling pump access and paint the outside while the inside is at negative pressure, it sucks paint into any penetration large enough to seep water. This is really important, air temp is usually warmer than water temp so every time you land the inside of the floats pressure lowers and any penetration below water sucks water. 

Reversing the process to pressurize the interior while spraying it should fill any and all penetrations that would admit water. It'd be a little trickier but the painter has to be wearing supplied air breathing gear and it doesn't take much positive pressure, maybe 2-3shop vacs cleaners pressurizing it would do. 

If you're connected to shore power install a dehumidifier to keep the bilges dry. A float switch in the dehumidifier's holding tank so it automatically pumps it dry. Hmmm?

If ALL you're concerned about is rust weld on some zincs. Stopping rust is what they're for. They're the sacrificial half of the galvanic process so they corrode instead of the hull.

Frosty The Lucky.

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thanks for your input guys... the modern approach is pretty much blast and epoxy...

the issue is that that's not often (if ever ) practical

the dutch system seems to be to grease the inside of a hull just to stop corrosion

I like this idea but grease smells not so good when you are sleeping above it

whalefat was used it seems on older hulls

I saw on the forum lots of folk talking about using blo and beeswax /turpentine mixes on bare steel and just wandered if anyone has any ideas.?

im going to experiment on some boots of plate with the blo/ turps /beeswax mix some of you guys seem to use as a finish

I always think listen to everyone and see what comes about.


there are many a boat yard stuck in various ways over here in the uk..

im tired of paint basically

internally that is...

thanks again.

here is a pic of my last creation in case of any interestnarrowboat bow pic

peace out .jim on the river somewhere...


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Frosty touched on the best alternative. However, it sounds like you may have limited access. Zinc (or any other anode) needs to have somewhat of a line-of-sight view to the area you are protecting. Its not exactly line-of-sight but the further "around the corner" the less protection it will receive. Even if you have a coating cathodic protection is needful. Holidays (spots missed by the coating) can actually concentrate the corrosion. In barges there should be an anode between each frame (both sides of the keel). Coatings will reduce the need, but not eliminate it. I suggest you contact a NACE certified corrosion tech who can evaluate the internal and external corrosion risks. BTW I once was NACE certified (long since expired) and I've never lived in a desert.  

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On 5/1/2022 at 6:30 PM, ThomasPowers said:

Boat advice from someone who  may live in a desert would be suspect in my opinion

I dunno Thomas,

ain’t y’all got a battle ship cannon barrel in the scrap yard there?

I think yall desert folks might be holding out some information on us!

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thanks guys just to confirm its only the bilges I want to protect and I may just test with some oil/grease mix just like the old fashioned approach seems to have been.... I will update if I make significant headway... thanks for all your time . best regards from the river ...somewhere....someplace...floatin around ;-)

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Bearing in mind Thomas lives in a desert so his opinion of other's opinions is just as suspect as other desert rats opinions of things nautical. 

While this idea would take time, maybe too much but here it is anyway. You could pour an appropriate quantity of emulsified asphalt in the hold and fill it with fresh water. The dilute emulsion would then contact all surfaces and leave a layer of asphalt when it dries. Emulsified asphalt "breaks" out of emulsion before the water evaporates. 

It's used to seal asphalt macadam pavement and for dust control on gravel roads here anyway. 

If you decide to grease your boat's innards I suggest vegetable grease and infusing it with a scented oil of your liking. Personally I like wisteria and having wisteria scented bilges makes me smile just thinking about it. Hmmm? Perhaps violet to aid sleep? I don't know about barges or long boats on UK canals but I've always slept like a baby on boats. The motion is the best sleep aid I know of. Well, maybe a strong shot of morphine but . . .:( 

Frosty The Lucky.

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When I worked in a shipyard, building and repairing barges and push boats, the interiors and exteriors were coated with coal tar epoxy , anodes were welded to the exterior of the boats, but not barges. I can’t say what it smelled like when applying, but it wasn’t pleasant when burning it off to make structural repairs. 

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Thanks for the link John, I love Irving Finkel's lectures, he's entertaining enough to make the information stick and intrigue you enough to delve more deeply. I highly recommend them!:)

The lecture points out a serious flaw in tarring the bilges, I don't know of a source of Iraqi bitumen and as shown Indian bitumen just won't do. I do know of a source of high quality bitumen though I don't know how available it is. "La Brea" bitumen has been water proofing structures, boats, vessels, etc. all over the American west for a millennia at least. California has been seeping oil since I don't know when, before humans on this continent anyway and the region known for the best and most was named La Brea by the Spaniards. La Brea being Spanish for "The Tar" so if you're interested, the world famous, "The La Brea Tar PIts" transliterates "The The Tar Tar pits."

About oil spills and the ecological disaster tar balls on west coast beaches. Humans have been collecting tar balls off west coast beaches as long as humans have been on this continent and wanted liquid proof stuff. Bet you didn't know how long native Americans have been trying to clean up the environment did you? :rolleyes:

Frosty The Lucky.

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First post here (account for lurking). I worked till recently at a repair shipyard in holland

If you decide to use grease or oil, you cannot paint later again. Paint will continue to come loose. Or you have to blast the steel and degrease.

Grease and oil works, but they float on water. I have done numerous repairs on bilges filled with grease (and water). The water rust the steel underfeed the grease. So regular grease and oil are a nogo.

You have special products for this, but they all fail. We had a client with inland vessels (fleet of 30+ boats). The dry tanks they conserve with soft coating (special oil). On ships they inspect every 3 months the tanks and re-apply the oil the tanks last 15 years. But they had ships with leaks after 5 years as well, because no inspection and re-applying. Compared with paint, same inspections, ships last over 20+ years, even in the ballast tanks. But again maintenance! Cracks in paint and the same will happen.

The dutch use it because it is cheap. And they sell before they have a problem ;)

I have seen anchor lockers that are filled up with (used) oils to conserve the chain and locker. And the chain still ends up in the forepeak, because of rust and thrust that the oil is wonder. Again, regular inspection.

I assume you have a bilges pump and a bilges well? So you can pump out the moisture? Helps a lot.

Coal tar is indeed super. If you still can find it (banned in Europe for almost 10 years now). But it will fail in bilges that come in contact with oils (oils dissolve the stuff, so water get underneath and it starts rusting from underneath). Wood tar paint (brown stuff) is still legal in eu. No experience on metal, they use it to protect wood (think wooden train beams).

Things that are well protected with oils or grease are stuff that water almost cannot touch. Think rudders or the nuts on rudders. Best grease i have seen is sheep grease, underneed protection caps on propellers to protect nut and shaft. But it stinks! So no use for you.

Did i mention regular inspection and re-applying? Also a good pump and a pump well. 

Keep in mind with soft coatings. Most shipyards will want you to clean (or pay to let them clean), so they can weld. The stuff burns easy. 

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