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First time blacking, advice needed


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Hi, as the title really, it's going to be my first time blacking my boat, a 50ft narrow boat.

Any advice appreciated, even tongue in cheek advice lol.

A few more specific questions, along where the rubbing strips attach to the main hull a previous owner seems to have put what looks like silicone sealant along them. These strips of silicone are basically falling off and its pretty rusty underneath, I'm guessing this isn't standard practice?

Boats out on a trailer for a week, I've got a pressure washer hired, probably buying the blacking from the chandlery....yeah, help please!

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On cheaper narrowboat shells, the builder saves money by tack welding the rubbing strikes every few inches, rather then continuously welding them top and bottom.

 

To prevent water ingress in the unwelded gaps, the builder often injects mastic into them. 

 

To sort this out properly, the rubbing stakes need removing, the rust sorting and if undamaged, the strikes replacing by continuously welding top and bottom. Not cheap.

 

Or you can bodge it by squirting rust converter such as Vactan into the gaps to convert the rust and then sealing with mastic before reblacking. 

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See if you can get the blacking cheaper at a builders merchants - it's basically the same stuff.

 

Now, let's have a good old CWDF argument about whether or not to black the baseplate.

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Blacked my boat for the first time last year. It's graft alright but not especially difficult.

 

Boat out of the water. Jet wash the barnicals off and old paint. Doesn't have to be down to the steel but you need a good solid base to paint over or it'll just come off. Long handled scraper to get the stubborn barnicals off, including those on the bottom of your boat. Should take you about 2-3 hours for this bit.

 

Oh, wear overalls. You'll get mucky.

 

Buy lots of brushes of varying sizes. Buy lots of roller blanks of varying sizes.

 

Once your hull is clean, get an angle grinder and roughen up the water line. Out with your bitumen paint and with your paint brushes start going over the water line. You'll want several coats. Three or four. Make sure you get into any cracks and crevices. Fill em with paint.

 

I used Keelblack when I blacked my hull. It works great and dries quickly. I'm about 7 months in with it and it still looks like new.

 

Once that's dried you'll be painting the rest of the hull. Out with the roller. Basically you're going to be painting over it several times. If you can do three or four layers, so much the better. Might as well if the boat is out of the water.

 

Make sure you paint your weed hatch and get paint up the rudder tube and on the rudder too. Anything that is under water wants paint on it.

 

Some people suggest you don't need to paint the bottom, others do. I didn't this time, because I was skint and couldn't afford the additional paint, but I will do next time.

 

You'll want as many layers of paint as you can, obviously letting it dry in between layers.

 

It's not rocket science but it's hard work. I'd definitely recommend Keelblack because you can get it done more quickly or at least get more layers of paint on.

 

Oh and good advice from Mike above, out of the water is definitely better unless you can hold your breath for hours at a time.

Edited by Guest
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We used the cheapest  small rollers for Belfast - the ones about 5 in long and 1.5 in diameter. Big rollers may appear to be quicker, but small ones really get in around all the rubbing strakes, rivets and welds and we barely used brushes at all. Stick them in a bucket of water overnight, then in the morning shake the water off and start painting again. At the end of the week throw the rollers, brushes and trays away.

We had some extra help one day but otherwise it was just 2 of us. In a week we managed to pressure wash a 70ft working boat hull and put 3 coats on below the water line, including the bottom, and 2 above (would have been 3 except we timed out). Also fitted in a hull survey and a few patches welded on, but they only got 2 coats of black.

But it was a hard week!

Edited by David Mack
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Two main bits of advice I was given.

Make sure you prep the hull properly and deal with any rust before you start blacking.

Give the blacking paint enough time to cure before putting it back in the water

 

I found it better to brush than roller, but that's just a personal preference

 

As David Mack says, it's hard work

Edited by 13-10
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Roller too fast and tiny bits of air get trapped in pits. Next morning they've popped and has to e done again. In fact rollering slowly, its just as quick with a brush. Let the first coat dry for at least 20 hours.

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Paint the bottom. Put on as many coats as you can. Check Keelblacks tech advice re overcoating intervals, too short and the first coats will not be dry enough, leave it too long and it will be too dry (might not apply to Keelblack but it applies to Epoxy and other stuff) Get those paper suits from Screwfix/Toolstation. Don't paint your hair. Don't worry about the rubbing strakes unless they are underwater. I, and many others, only use the good stuff below the water line, above the waterline I just bung on bitumastic from Screfix (actually Toolstation may be cheaper) Don't use foam rollers, the stickiness pulls out bits of foam. Don't paint the dog / partner / kids - paint is too dear to waste. Repeat in a few years.

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11 hours ago, Bussymcbusface said:

Thanks for all your advice! I've got a few weeks to prepare so I'll have a look round for paint, overalls, brushes, rollers etc, oh and probably vactan and mastic too, yeah it is just tack welded, thanks!

You can save on brushes and rollers by putting them in a bucket of water, in between doing coats of blacking, then shake the water off when ready to do the next coat. That way you only need one roller and one or two brushes, a big one and a smaller one. Oh, and use the cheapest brushes, you will be throwing them away afterwards.

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22 hours ago, Bussymcbusface said:

yeah it is just tack welded, thanks!

Make sure you push as much blacking into the gaps as possible. Really stuff it in. If water and air can’t get to it it can’t rust. 

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If you look at old metal structures, footbridges and the like and especially barges that have metal stiffeners and finishing strips riveted along the edges of gunwhales they eventually take the shape of many Loch Ness Monsters - a series of humps where the rust has forced the metal up, its a so and so of a job to repair this as the metal is always wasted away underneath, I have never noticed this happening on cheap and cheerful narrowboats where the rubbing strakes are probably only tack welded along the lower edge so maybe water doesn't penetrate underneath? However, if a length of half round rubbing strake was under the water I would be a bit wary of what was happening there, maybe even welding along the lower edge.

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On 03/05/2018 at 20:28, Neil2 said:

See if you can get the blacking cheaper at a builders merchants - it's basically the same stuff.

 

Now, let's have a good old CWDF argument about whether or not to black the baseplate.

I can’t resist. I cannot see the point in blacking the baseplate, there’s no light, and no oxygen there. The interface between the water and the air along the sides of the boat seems to me to be the place where it is important to have good blacking and good anodes. A short cruise down some of our shallower canals ( a lot of them these days) will remove the blacking from the bottom plate fairly quickly.

Edited by Stewart Kirby
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On 03/05/2018 at 22:19, jonathanA said:

Pay a boat yard to do it and save your holiday time for boating ! 

Good  option.

But also you might be saving just £50 quid doing it yourself.

When the boat is in dry dock or hard standing you could do lots of other jobs while the yard does the blacking. 

Painting the counter bands, or gunnels or welding something or whatever. 

 

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On 03/05/2018 at 22:20, Bussymcbusface said:

Thanks for all your advice! I've got a few weeks to prepare so I'll have a look round for paint, overalls, brushes, rollers etc, oh and probably vactan and mastic too, yeah it is just tack welded, thanks!

No probably definitely get some Vactan . Apply that to any rusted areas after you have wire brushed it . Like others have commented I find using a brush gets a thicker layer of paint on particularly in any areas that are pitted. It is a messy job but take plenty of before and after photographs and it makes it all worthwhile. I use Sealex B as a coating and have been happy with it although if the weather is cold it needs warming up to make it easier to apply .

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11 hours ago, Stewart Kirby said:

I can’t resist. I cannot see the point in blacking the baseplate, there’s no light, and no oxygen there. The interface between the water and the air along the sides of the boat seems to me to be the place where it is important to have good blacking and good anodes. A short cruise down some of our shallower canals ( a lot of them these days) will remove the blacking from the bottom plate fairly quickly.

Clearly the water line is the most important bit. But if you have pitting on the bottom plate, then effective cleaning and blacking will reduce the chances of the pits growing to the point where they come out the other side of the plate, even if all the high points got polished fairly rapidly.

The main reason most people don't black the bottom is because it is a pretty unpleasant job.

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12 hours ago, Stewart Kirby said:

I can’t resist. I cannot see the point in blacking the baseplate, there’s no light, and no oxygen there. The interface between the water and the air along the sides of the boat seems to me to be the place where it is important to have good blacking and good anodes. A short cruise down some of our shallower canals ( a lot of them these days) will remove the blacking from the bottom plate fairly quickly.

I think we need to get one thing straight, the notion that rusting does not occur on the baseplate is clearly nonsense.  In fact the popular view that the waterline is the most vulnerable area doesn't stand up to any examination of the evidence either.

 

The issue is whether it is worth the trouble of blacking it, given the vulnerable environment the bottom of a narrowboat lives in and as David says, the fact that it is an extremely unpleasant job.   

 

A lot of folk are swayed by the anecdotes about elderly boats where the unprotected bottom still looks like new.  I think this could very well be the case with certain deep draughted boats, say 2'6 and greater where the baseplate is getting scoured on a regular basis and rust never gets a hold.  But modern shallow draught boats generally float well clear of the canal bottom, unless you happen to do most of your boating on the Ashby or the HNC.

 

So, my proposition is don't bother if you have a heavy deep draughted boat (that might well have a bottom plate in excess of the normal 10mm anyway) but consider it worthwhile if you think your boat floats well clear of the canal bottom most of the time.    

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1 hour ago, David Mack said:

Clearly the water line is the most important bit. But if you have pitting on the bottom plate, then effective cleaning and blacking will reduce the chances of the pits growing to the point where they come out the other side of the plate, even if all the high points got polished fairly rapidly.

The main reason most people don't black the bottom is because it is a pretty unpleasant job.

Plus, in some facilities virtually impossible to get suitable access

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On 03/05/2018 at 17:22, cuthound said:

On cheaper narrowboat shells, the builder saves money by tack welding the rubbing strikes every few inches, rather then continuously welding them top and bottom.

 

To prevent water ingress in the unwelded gaps, the builder often injects mastic into them. 

 

To sort this out properly, the rubbing stakes need removing, the rust sorting and if undamaged, the strikes replacing by continuously welding top and bottom. Not cheap.

 

Or you can bodge it by squirting rust converter such as Vactan into the gaps to convert the rust and then sealing with mastic before reblacking. 

I'd agree with this apart from the last bit. That bodge will just make a proper repair more difficult.

 

If you can get the rubbing strakes fully welded while the boat is out of the water that's all you really need to do. I don't think you need to remove them first to sort the rust out. Any rust that's already underneath will be fine as long as it doesn't continue. If there's a bit of water or dampness between the rubbing strake and hull then it will probably get boiled off by the welding or you could go around with a blow torch and try to dry it out first. Even if you can't get rid of all the trapped water then a finite amount of water and air will only cause a finite amount of rusting. So just get them welded top and bottom and that's it.

1 hour ago, Neil2 said:

I think we need to get one thing straight, the notion that rusting does not occur on the baseplate is clearly nonsense.  In fact the popular view that the waterline is the most vulnerable area doesn't stand up to any examination of the evidence either.

 

 

All the evidence I've ever seen from my own boats and others suggests that the waterline is indeed the most vulnerable area.

Edited by blackrose
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3 hours ago, Troyboy said:

No probably definitely get some Vactan . Apply that to any rusted areas after you have wire brushed it . Like others have commented I find using a brush gets a thicker layer of paint on particularly in any areas that are pitted. It is a messy job but take plenty of before and after photographs and it makes it all worthwhile. I use Sealex B as a coating and have been happy with it although if the weather is cold it needs warming up to make it easier to apply .

Vactan is shite used by amateurs. I don't know why we bother with it. Oh wait, we are amateurs! 

 

Seriously I've used it on my boat and yes it turns the rust black and converts it and that seems great. But the polymer coating doesn't last very long in damp environments - not in my experience anyway and it's not a great base for subsequent coats of paint so then the rust comes back. Having worked prepping and painting the inside and outside of rivetted steel boats for a couple of years in a boatyard I'd never use Vactan on my own boat again. Instead I'd always prep properly and use a decent two pack epoxy. Probably not an option for the OP if his/her boat is blacked with bitumen but just saying that Vactan is not the way forward.

Edited by blackrose
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We use large wire brush (cup type) on angle grinders to prepare for blacking. A light weight grinder is easier on the wrist.

Don't neglect the weed hatch and it's cover.

Give the welder plenty of notice if you need new anodes  welding on.

Try to leave 24 hours between the last coat and relaunching if you possibly can. This isn't always possible if you're paying a yard to do the work.

Edited by Peter-Bullfinch
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