Painting metal in the bilge

[whiskerstay]

One of my minor tasks for this winter is to clean up and paint some of the metalwork that strengthens Crystal's Elm frames, and some around the engine mountings too.

Can anyone recommend anything with a proven track record for rustproofing and looking attractive that won't upset the wood, will be waterproof, etc. etc. - basically, what's good for bilge-metal?

Cheers,

/<

<hr width=100% size=1>"Stop mucking about, darling, and get the bloody mud weight over."

 

[Peterduck]

You have "Crystal" do you? You lucky duck! I always thought that to be a particularly nice design. Which metals are you faced with in the bilge? Iron floors would require a different approach to bronze ones.
Peter.

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[Mirelle]

Er, um, no, I don't really know anything that will do much good on ironwork, short of having the bits out and re-galvanised, and if they have absorbed a lot of salt, as is likely, even that won't work. Galvafroid is one possibility, red lead is another, often favoured by professionals, and Stockholm tar has a following!

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[whiskerstay]

Yes, she's ours (girlfriend and I), as of about three weeks ago. I think it's safe to say we have been very lucky, in that lots of things happened at the right time to make it a possibility. Now I'm in the paranoia stage!

According to the survey, the metal in the floors is steel or wrought iron, and the engine mounts and floor are of steel. The bronze down there seems quite alright. The surveyor recommends corrosion-inhibiting paint - something like Hammerite, I presume - but I don't want to use anything that might upset the wood.

Many thanks,

/<

<hr width=100% size=1>"Stop mucking about, darling, and get the bloody mud weight over."

 

[mickshep]

Hi Kris. When faced with same problem on Janina I removed the surface rust by first chipping then using a drill mounted heavy duty wire brush (mind the wood). I then pressure washed the surface in the hope of removing ingrained salt/grease etc. then all surfaces well and truly blathered with V.C Tar II followed by a couple of coats of bilge paint. Up to now (3 Years) no rusting evident so must be reasonably good. Have to say I was surprised at how much loose flakey rust can be removed without significantly reducing size of floors. By the way where can we see photo's of your new yawl? Cheers, Mike

<hr width=100% size=1>"Naaa mate, she's made of tin"

 

[Plum]

Why not remove the parts and have them grit blasted and then hot dip galvanised? This is the only long term solution for steel/iron parts (other than replacing them with bronze NAB). If you are going to paint the metal surfaces that are in contact with the wood you have to remove them anyway. If you are not going to remove them then you will never stop corrosion from the unpained surfaces eating away at the edges of your new paint system.

If you really want to paint, I have had good results on engines with Hammerite No.1 Rust Beater Primer followed with hammerite smooth.

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[penfold]

It's highly unlikely that any kind of metal paint will have a detrimental effect; I'd go right ahead and slap it on. On the other hand, it's possilbe the the corrosion products have harmed the wood, but the surveyor would have picked that up if it was a significant problem.

cheers,
david

<hr width=100% size=1>This candidate has low personal standards, and continually fails to meet them.

 

[whiskerstay]

At the moment, I'm looking for a quick-fix as she is staying in the water this year (due to a very late launch by previous owners) - when she's out next winter, I think this sounds like the way to go. It's only cosmetic at this stage, so just a little preventative work should suffice for the coming season.

Would eventual replacement with bronze be beneficial (expense aside)?

Mike, I was thinking about getting one of those little Dremels for small jobs around the boat. Do you think it could do the wire brush work, or would I need something a bit more hardcore?

Photos of Crystal will be available shortly on her soon-to-be-uploaded website.

Cheers,

/<

<hr width=100% size=1>"Stop mucking about, darling, and get the bloody mud weight over."

 

[Plum]

Painting as a short term measure before hot-dip or remake in Bronze sounds line a good plan. Bear in mind, though, that the galvanising companies hate any trace of paint on items to be galvanised so you will either have to remove it all or pay to have it grit blasted off. If it is only for a year, why not wire brush and then wax-oil? Won't look so nice, but will significantly slow the rust and is easy to remove before galvanising. I have no idea of the cost of bronze replacements but I am sure it will be EXPENSIVE. Good hot dip galvanising will last for at least 15 years in a bilge and can always be repeated.

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[mickshep]

IMHO The Dremmel is a bit light for serious rust removal. As a matter of interest are the floors riveted or bolted? The four forward floors on Janina had been replaced as a result of over enthusiastic fitting of anodes, and having seen how it was done I would see very little problem with removal one at a time, regalv' then refit, By removing one at a time you're minamising the risk of any movement. Good luck. Mike.

<hr width=100% size=1>"Naaa mate, she's made of tin"

 

[whiskerstay]

Mike,

Have just discovered that the Dremel is down to 76 quid, so I'm going to get one anyway, although I think you're right about the rust removal job - sure it will be useful elsewhere... somewhere!

I'm not too sure about the floors - am currently at work, so can't check the survey - but I gather that the metalwork is reinforcement, so removal shouldn't cause any significant movement problems. That said, I'd still rather do one at a time due to the amount of time I have to spend with her at the moment.

She's only been ours for about three weeks, so haven't really got down and dirty with her construction and modifictions yet.

If you'd like to see a picture, click here.

Cheers,

/<

<hr width=100% size=1>"Stop mucking about, darling, and get the bloody mud weight over."

 

[Peterduck]

That's just "Bewdiful"! Shame about the post getting in the way of the mizzen mast, isn't it? Certainly, if floors are to be removed it shouild be done one at a time, but galvanising is prohibitively expensive this way unless you know someone who can slip your piece in with a whole lot of others. Galvanisers here in Melbourne charge a minimum of $80.00 per job, and it's amazing how much you can get done before the price starts to rise past the basic amount. If you had to pay $80.00 per floor, it would be cheaper to get them remade in bronze. A 10% solution of molasses is a wonderful rust remover, but the article has to be steeped in the solution for a week or so.
Peter.

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[whiskerstay]

I was quite amused at the post, almost replacing the mizzen! Glad you like her in the "flesh". There is marginally more mizzen in <A target="_blank" HREF=http://www.krishansen.co.uk/cryssml.jpg>this one</A>.

I'm going to see her in the next day or so, so will get the floorboards up and have a proper poke about to see how much needs to be done, and will report back. I'm also desperate for a bit of action, if only under power, so I think we'll go down and visit Nancy Blackett at Felixstowe Ferry, who only has another week in the water - maintenance issues might be overriden by a desire to get out on the river again!

Cheers,

/<



<hr width=100% size=1>"Stop mucking about, darling, and get the bloody mud weight over."

 

[mickshep]

Now that is a pretty boat. Re the galving, I have a contact but in the North East, He fits in work around other jobs so very cheap, but a long way from you. Mike.

<hr width=100% size=1>"Naaa mate, she's made of tin"

 

[Casey]

Before you invest in a Dremel take a look at a Minicraft. Similar sort of thing but half the price!

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[Plum]

Me again! If you go the re-galvanising route, you may want to try Par Galvanising at Rayleigh, Essex. Although in theory he has a minimum weight per job, if you talk to him and explain it is a boat job and you will pay cash, he will do smaller jobs.

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[ongolo]

Good Evening,

I have followed the thread on painting the bilge. I have not had any experience in wooden boats, but I live in one of the two most corrosive places in the world I believe, and had to do some experiments to protect my 55ft steel hulled Gaff schooner.

I have made some experiments, the results of which seem at first ridiculous until you get to investigate the chemistry and the ph values of it.

Of the many experiments for preventive maintenance on rusted (loose rust removed by chipping, brushing scraping) two stood out best.

The lesser uses one of the new water based primers on a rusted surface which are hardly completely dry. The water based primer soakes up any moisture to dilute itself. Then we used a water based epoxy system over that and any old paint of our choise to protect the water based epoxy. The trick is that over painting of the epoxy must be done at the right time which you have to experiment with and depends upon temperature and other factors. If you paint too soon with a solvent based paint over the epoxy it might not cure completely or the solvent penetrates it and softens up the underlaying layer of primer. Painting to late and the subsequent coat will not adhere to the water based epoxy.

My choice is chlorinated rubber in the form of pool paint because it dries so quickly.

The other experiment wich appears ridiculous is that I mixed a solvent based paint with building cement to a thick paste. The paint is only a binder for the cement. I used a cheap spray paint from Plascon called CATERPILLAR YELLOW or as we call it CAT Yellow. But I have also used chlorinated rubber mixed with cement, I think any solvent based paint will do. The consistency must be almost like a paste and it appears that a) any humidity on or in the steel is soaked into the grains of cement in contact with the rusted steel and ,

b) the alkaline properties of the cement prevents the steel to rust further (hopefully without side effect in your wooden boats)

after this cement treatment I use again a water base epoxy as a barrier before a paint of my choice goes on.

The cement does protect the steel, but if you have to take the paint off, the cement paint mixuter brakes off fairly easy and will take the rust with it. Some time I have observed that an almost clean metallic grey surface was the result, which would be ideal for over painting again, but the result of this I cannot say yet.

That was now my five cents worth, but if it does not work for you, dont try and sue me. That does not work at 22 south and 15 east. )

regards ongolo


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[Mirelle]

That makes very good sense to me. There is no doubt that the cement in the bilge of my wooden boat (it is there to allow the bilge water to drain quickly back to the sump) protects the iron floors where they lie under it. And I like the idea of using water based paints.

<hr width=100% size=1>Que scais-je?

 

[petercrook]

"Would eventual replacement with bronze be beneficial (expense aside)?"

Depends on what other metals are used under the water-line - see the thread on bronze castings.

Cautious Clara's floors were (wrought?) iron, most of which had been replaced with mild steel straps covered in some black substance. One at least of the latter is now rusting badly (it's all surface rust at the moment so won't affect its strength, but it does make for a filthy bilge). The original floors were also rusting badly and the futtocks to which they are fastened were showing signs of electrochemical decay (going soft).

We chipped the rust off the iron floors and painted with Hammerite Rust Remover and Hammerite smooth earlier this year (the boat was afloat when we bought her and we didn't want to haul her out). This seems to have been reasonably effective so far. As the boat is now ashore we decided to remove the most corroded floor and replace it with a cast bronze one. We're glad we did because it fell apart as we took it out!

We're replacing the floors with bronze because Cautious Clara has a lead keel, bronze keel bolts and copper/bronze fastenings. If she had had an iron keel, iron keel bolts and iron floor fastenings we would have tried the wrought/galvanised iron route. After all, the original iron floors have lasted 93 years, so if you do the same I guess they will see you out!

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[Gordonmc]

The trim-balast in "Flap" is iron pigs which have been rusting away happily for a few decades. In terms of weight loss, this is negligable but it does mean the bilges are covered in a layer of oxide... which means pumping the bilges has to be done in the dead of night with no-one watching.
In the realisation I will have to lift the floors and treat the pigs I have been doing some experiments with some easily accessible ones.
Traditionally coated in pitch; wirebrushed, primered and painted; wirebrush and waxoyl and finally a coat of Finnigan's car underbody paint with a waxoyl base.
I will be doing all of the pigs with the latter.
It is the least messy in application and should be OK in the future if I have to re-trim. So far it has been the best in stopping rust reappearing.

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