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Boat Painting


AndyP

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Hi all 

 

just wondering what methods everyone employs for painting / maintaining their boats especially wood construction or wood and metal construction hulls?

 

I've created this myself to show a preferred preference for painting but wondered if anyone else had any tips tricks or shortcuts better than mine listed and what kind of paint you are using ?? (thinking more fresh water and canal than salt based by the way ) 

 

my list of preparation and paint prep is here: https://www.ultrimaxstore.com/blog/freshwater-and-canal-boat-paint-everything-you-need-to-know/

 

any help appreciated 

 

br

 

Andy 

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Gordon Bennett ....... another one!

 

"If I start my advert off with a question, then suggest my own views followed by a request for help from them.  Nobody will suspect my link leads to my website where they fill out their details!!!!

 

 

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it wasn't really our intention to advertise - we were advised by a member John Gregory who we helped with our tech advice to paint his boat correctly seems a lot of people are still tarring boats which is a pretty old practise. He thought it might be a good place for us to swap some ideas on poeple trying other paints and techniques that we might be interested as a trade off. We're more than happy not to be here though if the articles aren't welcome ?  If so please just delete my login @admin

 

br

Andy 

 

Ultrimax 

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2 hours ago, AndyP said:

it wasn't really our intention to advertise - we were advised by a member John Gregory who we helped with our tech advice to paint his boat correctly seems a lot of people are still tarring boats which is a pretty old practise. He thought it might be a good place for us to swap some ideas on poeple trying other paints and techniques that we might be interested as a trade off. We're more than happy not to be here though if the articles aren't welcome ?  If so please just delete my login @admin

 

br

Andy 

 

Ultrimax 

I would suggest that if what you say is true Mr Gregory may not be the best source of information re canal boat painting because he has, probably unintentionally, given you incorrect information. The vast majority of canal boat hulls are blacked but for a number of years the tar based blacking has been made unobtainable unless some old stock can be found. Most of the blacking is bitumen based with increasingly two pack backings becoming popular. The cabin sides, roof, etc and   often above the top guard (rubbing band) are painted. The majority with oil based paints that are brush applied but sprayed and two pack alternatives are becoming more popular.

 

As for the hull blacking. Unless the boat stays moored up in the marina for 100% of its time it is impossible to avoid bumps and scrapes so whatever coating is used the mechanical damage needs addressing regularly. Although two pack is more abrasion resistant that ordinary bitumen based blacking it will still get damaged so instead of hauling out every two years or so for pressure washing off and re-blacking a two packed boat needs it every five years or so - maybe pushed up to 10 years. However the steel perpetration for the popular two packs involves blasting and for maximum longevity expensive hot zinc spraying of "undercoat" or the application of zinc rich paint. All this is expensive and the fact well looked after boats well in excess of 39 years old are still perfectly serviceable despite only having bitumen blacking to many suggest the extra expense of "modern" hull protection can't be justified.

 

As far as topsides are concerned many boaters,  especially of older boats, paint the boats themselves. Often canal side in the open air so sprayed two pack, or even sprayed one pack is not a suitable choice. Single pack oil based paint has been proven to be the most likely to give acceptable results. Professional painters who have access to heated covered wet docks are starting to offer two pack and/or sprayed painting but apart from sprayed new builds I get the impression its still the minority. For many boaters who can afford a professional repaint a traditional hand painted look is important so that again tends to indicate an oil based single pack paint.

 

I hope this helps you understand the market. I am some kind of engineer, not a painter but it is what I see around the system.

 

PS - I don't follow links from posters with little history.

Edited by Tony Brooks
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Hi Tony 

 

 

thanks for the comment 

 

the only additional I can comment is - we tend to provide coatings and training for organisations like the MOD, tanker companies etc in term of our boating experience. As you say rightly 'blacking' is being phased out as (I'm a former oil man) and can advise it is hideously bad for the environment and is graded a low bi-product of oil and as such isn't filtered as rigorously as other blends. The govt has therefore clamped down on this rough blends as they are known because they contain too many polymers and 'dirty' branch connectors at the microscopic level that cause colossal damage to the environment. 

 

That said it's also a very inefficient product - it is very difficult to apply in an even paint film thickness ratio and it's nature to retain moisture and flexibility means it inevitably scrapes off far quicker than traditional coatings. As you say as the tops of boats, decks etc have and still are traditionally painted anyway it makes sense to bring freshwater boats into the 21st century with more robust paint systems such as Jotun J90 as a primer and undercoat and top it with something like Jotun Hardtop (which can also be used for the above waterline areas). Maintaining a same brand paint system is always advised as they react less negatively with each other and have been designed for best protection performance and aesthetics. 

 

Yes with self-build marina spraying the 2 Pack spraying isn't always viable, but most Jotun paints even the two packs can be rollered on or brushed on which makes them so dynamic for boat painters. If the 2 pack nature still worries some and the applied respiratory complications it can cause without the proper respiratory protection. Then there are now Isocyanate free 2 pack paints available that can be sprayed with standard equipment and in open air. 

 

Hope that gives a bit of background as to why we suggest the painted coating system methods now even for freshwater owner / self builders as the pro equipment and systems that we used to exclusively offer to the pro's are now being made available to a wider market and making techniques such as blacking redundant.

 

br

 

Andy  

 

 

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3 hours ago, AndyP said:

...making techniques such as blacking redundant.

The only reason most of us stick with blacking (no pun intended) is that we have to do DIY hand prep, generally a pressure wash followed by hand scraping.  This inevitably leaves some residual bitumen, no matter how assiduous we are, whilst most 2 pack epoxy coating manufacturers demand SA2.5 prep and also specify long curing times before immersion. Your statement above make it sound like thise obstacles are not insurmountable. What are your recommendations?

 

 

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I decided to stick with blacking mainly because it is cheaper at least in the short term. I am rather happy to have the boat out of water every couple of years anyway to see what the condition is. I'd feel quite uneasy every time I experienced an underwater bump or scrape if I knew that it would be up to 10 years before I could see whether it damaged the epoxy/blacking. I don't know if that's paranoid but I have nightmares about a hole developing and the boat sinking!

 

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As has been said, commercial advertising on the site is, as per the forum rules and guidelines you agreed to on joining the site, only permitted with permission of myself as site owner. 

That's not an ego trip thing, it's an avoiding having the site full of spam, giving me an opportunity to ensure you get off on the right foot with the members thing. 

 

However, given we are where we are, and the products your selling are boat related and may if use to our members, I'm happy for this thread to run, but would ask you not to dredge up old threads to post 'information' and links to your site etc.

 

Cheers.

 

Daniel

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3 hours ago, Sea Dog said:

The only reason most of us stick with blacking (no pun intended) is that we have to do DIY hand prep, generally a pressure wash followed by hand scraping.  This inevitably leaves some residual bitumen, no matter how assiduous we are, whilst most 2 pack epoxy coating manufacturers demand SA2.5 prep and also specify long curing times before immersion. 

While as I understand it you dead right that many coatings will not go over bitumen, it's also a myth that you can't hand prep before applying epoxy coatings, or that the cure times are problematic. 

 

Our boat was blasted to bright steel when new 30 years ago, but has been overcoated with pressure washing and hand prep only ever since, which has given excellent performance and prevented effectively any corrosion at all of the hull. 

 

We use Lieghs Paints (now Sherwin Williams) from Bolton including for the cabin and would recommend it to anyone. Epoxy aluminium primer and undercoat, but a single pack vinal blacking over the top. 

 

2 hours ago, ivan&alice said:

I decided to stick with blacking mainly because it is cheaper at least in the short term. I am rather happy to have the boat out of water every couple of years anyway to see what the condition is. I'd feel quite uneasy every time I experienced an underwater bump or scrape if I knew that it would be up to 10 years before I could see whether it damaged the epoxy/blacking. I don't know if that's paranoid but I have nightmares about a hole developing and the boat sinking!

For me the cost difference in paint is negligible compared to the cost of the drydock, pressure washer hire, my own time doing the job, and the boat.

 

At which point if using decent paint means you can dock every four years not every two years, your laughing all the way to the bank the amount saved.

 

Although it feels awful at the time the amount of paint removed from bumping something while using the boat is tiny and almost all on the rubbing stakes. I would say the amount of bare metal on our hull after four years is less than a side or a4 reliably.

 

Daniel

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On 13/11/2020 at 17:49, Sea Dog said:

The only reason most of us stick with blacking (no pun intended) is that we have to do DIY hand prep, generally a pressure wash followed by hand scraping.  This inevitably leaves some residual bitumen, no matter how assiduous we are, whilst most 2 pack epoxy coating manufacturers demand SA2.5 prep and also specify long curing times before immersion. Your statement above make it sound like thise obstacles are not insurmountable. What are your recommendations?

 

 

Hi @seadog  yes think a good pressure wash and some back breaking scraping of the blacking is prob the best way to go for the diy'er (light blasting if you have it on drydock and are paying someone). The residual bitumen issue yes no big tips round it other than elbow grease as you want the surface as good as possible for the new coating but perhaps if you see it that bitumen blacking won't be around in the very near future unless you have a stockpile you'll be doing it at some point soon anyway. The 2 pack don't forget can be brushed and rollered on if you use a product like Jotun Jotamastic 90 on the hull and if you choose wintergrade rather than standard (still a 2 pack , still brush or roller) then it dries quicker, protects against a more severe marine setting (ie: its often used to protect the legs of oil rigs) so you get a better coating, with better marine properties If you also look at the cost paypack then these coatings will last 10-15 years against a blacking of about 2 so a no brainer really. Saw an interesting comment above about the FOMO fear of missing out - as in the boat owner likes to have the boat out to check every two years for damage and then do the blacking. Don't think there is anymore risk of damage with 2 pack coatings as there is blacking so if you really want to take the boat out every 2 years then do and just touchup if neccessary with a brush or roller...and enjoy more time looking after the aesthetical side of the boat rather than the boring maintenance areas! 

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1 hour ago, AndyP said:

Hi @seadog  yes think a good pressure wash and some back breaking scraping of the blacking is prob the best way to go for the diy'er (light blasting if you have it on drydock and are paying someone). The residual bitumen issue yes no big tips round it other than elbow grease as you want the surface as good as possible for the new coating but perhaps if you see it that bitumen blacking won't be around in the very near future unless you have a stockpile you'll be doing it at some point soon anyway. The 2 pack don't forget can be brushed and rollered on if you use a product like Jotun Jotamastic 90 on the hull and if you choose wintergrade rather than standard (still a 2 pack , still brush or roller) then it dries quicker, protects against a more severe marine setting (ie: its often used to protect the legs of oil rigs) so you get a better coating, with better marine properties If you also look at the cost paypack then these coatings will last 10-15 years against a blacking of about 2 so a no brainer really. Saw an interesting comment above about the FOMO fear of missing out - as in the boat owner likes to have the boat out to check every two years for damage and then do the blacking. Don't think there is anymore risk of damage with 2 pack coatings as there is blacking so if you really want to take the boat out every 2 years then do and just touchup if neccessary with a brush or roller...and enjoy more time looking after the aesthetical side of the boat rather than the boring maintenance areas! 

Thanks for your views Andy. SML are now doing a 2 pack they say is tolerant of residual bitumen, so appears to be a potential DIY job. Do you have any experience with that?

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I can see that painting almost anything over a significant amount of bitumen would end badly, just because it is so soft and different to anything else, but if Andy and or SML are saying there are paints where you can just scrape it back to the steel and then apply, without having to either remove it with solvents and or mechanical blasting that would I think be very interesting as I dont have any experience of that.

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40 minutes ago, matty40s said:

With most boatyards, the WinterJotomastic is the only viable option with the specified drying times of the others in the range. 

Certainly in the winter months, although having looked at the cure times, in a warm/summer day the standard grade would be fine.

 

We have used two-pack paints on our boat from new, but also done all of our own dry docking, so have first hand experience of it, and have had not issues at all fitting it in with the normal narrowboat/canal "one week on a drydock, pressure wash and a bit of scraping only" routine and if anything would say we do less prep work than most, because the surface we are left with is so much better than you would normally get. Always roller+brush not spray. Most of the dry docks we have used* have two boats on at a time and and it is always staggering to me to see the state of the boat on the other side, who are equally bowled over when we tell them out boat hasn't been out for 4 years as they assume we're on for an inspection or something else other than re-painting!

 

*Worsley originally, then Middlewich, and recently Northwich as we know them well.

 

 

Below is an extract from the invoice for our paint from last years drydocking and roof repaint.

  • Sherwin Williams M535 - Formerly Leighs Resistex (Black) - 5 Ltr £60.11 x3 £180.33
  • Sherwin Williams Macropoxy M902 - Formerly Leighs Epigrip - 2 Ltr £46.83 
  • Sherwin Williams Acrolon C137V2 - Formerly Leighs Resistex - 5 Ltr £103.37  

The blacking (M535) describes itself as "a single pack, pitch free, vinyl copolymer resin based underwater coating" and goes on lovely with a med-pile 9" roller, brush or 4" roller for smaller areas, and flashes off to touch dry in a few hours and needs no more than a day before going in the water. Two coats over everything, having repaired and primed any bare metal or damaged areas in a coat or two of epoxy ali. 

 

The epoxy ali (M902) is a two pack epoxy 'winterfast' high build brushing aluminium primer "for application onto hand or mechanically prepared surfaces" which does exactly as it says on the tin, and is I believe fairly similar to the Winter Grade Jotomastic90. It still like the preverbal to a blanket, goes off a treat, and you really can trowel it on. It even says you can apply it to damp substrate although we obviously aim not to.

Mainly we apply by brush as smaller areas but it will also go on with a 4" roller, and although it doesn't work on vertical surfaces, I have also smoothed gouges in the deck/roof using it with a pallet knife! It also comes in 2l qty which is all we need.

 

We also used Dacrylate's "Epidac 2 HB" epoxy aluminum for the first time last year as its what Northwich supply and use, so we gave the base plate a coat of it ahead of the blacking, including a series of test-patches two wards the rear testing it against the M902. It appeared to cure to a softer finish, but that might just be the time scales. Northwich also typically airless spray, which Matt says if nothing else is a much easier way to achieve the recommended film thickness which you typically can't get with a roller. I will let you know the outcome of the tests in three years time!

 

Originally the boat was blasted to bright and painted with Metagard L574 Blast Primer - (5l for about £50) which is a lovely thin two pack primer which really does stick well, and 30 years later you can still often see it clinging on in scratches were the blacking would otherwise be back to bare metal. We have also used Epigrip J984 which is a zinc-rich epoxy primer (5l for £100) rather than the ali, but if nothing else only coming in 5l qty which we don't have use for.

 

We also once went 5 years between dry docking due to external commitments, and the boat was absolutely fine. I would certainly be both better than most get with 2-3 year intervals, and very viable if cost was an important consideration. However did appear to be noticeably more areas needing treatment ahead of recoating and we decided we would aim to stick with 4 yearly docking.

 

For the cabin we also use a two-pack paint (the C137V2) which is "a high performance fast drying acrylic urethane gloss finish for use where long term exterior gloss and colour retention characteristics are required" as the top two coats for the cabin, there is also an non-gloss version (C237)  for undercoating, the £100 cost includes about £25 extra for 'special colour' range, so the undercoat is £70 a tin as you don't need the 'special colour' range! Goes on well with a 4" foam roller cut in with a brush, although you have to work fast to keep a wet edge doing the roof particularly in summer. You get a smart looking the finish, but it is more 'business like' than 'coach work' as you do retain the rollered finish.

We use the boat plenty, walk all over the roof, and find it does us very well. You get significant chalking over winter 4-6 years in but it will come of with a scrubbing brush, and certainly you don't get any other issue even 8 years in, by which point we have recoated it for esthetics and because we are going through to the undercoat in the higher traffic areas of the roof/decks. 

 

I could talk about this all day, can provide photos (at least a link to my fb album) if people are interested, and am also very happy for anyone who wants to come a look at the boat when we do dry dock next, due around Sept 2023.

 

Daniel

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33 minutes ago, DHutch said:

The blacking (M535) describes itself as "a single pack, pitch free, vinyl copolymer resin based underwater coating" and goes on lovely with a med-pile 9" roller, brush or 4" roller for smaller areas, and flashes off to touch dry in a few hours and needs no more than a day before going in the water.

Unfortunately Daniel, despite the rebranding from Leigh to Sherwin Williams, this appears to have been discontinued. :(

 

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2 hours ago, Sea Dog said:

Thanks for your views Andy. SML are now doing a 2 pack they say is tolerant of residual bitumen, so appears to be a potential DIY job. Do you have any experience with that?

Hi yes we've seen this one Ballastic? it does appear that you can coat over bitumen with this one. I don't have any experience of how it actually performs but I guess from a paint manufacturer point of view I can only advise if a customer advised they had placed a paint over a previous coating then the new say the new coating failed. You would never advise the failing is with the new coating as the surface has had insufficient preparation. So I guess it could be seen to a diyer to save time and if all goes well then great. If there is a failing across the entire hull then it would definitely be a 'on your head be it' clause if you admit to placing it over a previous coating without surface preparation back to the original substrate. 

 

horse for course perhaps on that one !

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On 16/11/2020 at 08:53, AndyP said:

Hi @seadog  yes think a good pressure wash and some back breaking scraping of the blacking is prob the best way to go for the diy'er (light blasting if you have it on drydock and are paying someone). The residual bitumen issue yes no big tips round it other than elbow grease as you want the surface as good as possible for the new coating but perhaps if you see it that bitumen blacking won't be around in the very near future unless you have a stockpile you'll be doing it at some point soon anyway. The 2 pack don't forget can be brushed and rollered on if you use a product like Jotun Jotamastic 90 on the hull and if you choose wintergrade rather than standard (still a 2 pack , still brush or roller) then it dries quicker, protects against a more severe marine setting (ie: its often used to protect the legs of oil rigs) so you get a better coating, with better marine properties If you also look at the cost paypack then these coatings will last 10-15 years against a blacking of about 2 so a no brainer really. Saw an interesting comment above about the FOMO fear of missing out - as in the boat owner likes to have the boat out to check every two years for damage and then do the blacking. Don't think there is anymore risk of damage with 2 pack coatings as there is blacking so if you really want to take the boat out every 2 years then do and just touchup if neccessary with a brush or roller...and enjoy more time looking after the aesthetical side of the boat rather than the boring maintenance areas! 

The problem we have with narrowboats is that 2 pack epoxies dont always meet expectations for the hull coatings. Yes, 10-15 years performance is possible from epoxies but performance is badly compromised when you bend the rules. Epoxies work as a barrier coating ie when applied at the right thickness they reduce the permeation of water/oxygen to an low level and the excellent adhesion stops the coating 'lifting'/'undercutting' and allowing water/oxygen onto the steel surface. Any reduction in adhesion is going to reduce lifetime.

I spent 10 years managing a technical team developing surface tolerant epoxies for the oil industry (focussing first on splash zone coatings). Yes they work but they are a compromise. Blast to SA2.5 and you get a good surface to adhere to. Anything less is a compromise. Yes you can overcoat old epoxy coatings as long as the original coating is adhering well – and you abrade the coating to get a key. A well applied epoxy to SA2.5 steel plus touch ups every 10 years can work very well.

Bending the rules by trying to apply epoxy to residual bitumen is not a good idea. The residual bitumen will not be adhering anywhere near what an epoxy demands so premature failure likely. Will you get 5 years? Maybe. Will you get 10 years? No. Any surface tolerant epoxy applied on a less than perfect surface (SA2.5) will be a compromise. Trust me. For best performance, epoxies need the best adhesion.

The other thing that bugs me about all these epoxy 'options' are the ability to apply at low temperatures. Once again, another compromise. Epoxies work and cure very well at 20°C. 'Normal' epoxies work ok down to 15°C but that is the limit. There are two factors. One is speed of cure (and obviously that is slowed down at low temps) but more importantly is the flow of a coating. A normal epoxy will not flow as well at <15°C so will not 'wet' the surface as well as it should which impacts on adhesion. Ok, you say, lets throw in some thinner to make it flow – but that is not how the coating was formulated and extra thinner just makes the cure longer (and less!) and how do you expect that extra solvent to evaporate out of the coating. I'm not even considering the chance of condensation on the surface with ambients < 15°C and steel temp considerably lower.

Ok, the response from the paint industry is to change the cure so that the epoxy cures at lower temperatures – even down to 0°C – but those cure systems are a compromise (again!). Total crosslinking is likely to be lower so the finished coating will not be as hard (and permeation is compromised). Lower temps again mean less wetting of the surface and moisture is far more likely to be present. Most epoxies use solvents that are difficult to get out once you get down to 10°C so likely a winter/spring applied coating will be compromised with residual solvent acting as a 'plasticiser'.

All in all, it is impossible to get an epoxy to perform to 100% when needing surface tolerance and low temperature application so the 10-15 year target can be a dream. We worked on some very innovative routes to improved performance using the output of a huge research department and ended up knowing that painting with epoxy in the UK is restricted to a limited number of months a year if you want best performance. Maybe compromised performance is ok for narrowboats?

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18 minutes ago, Dr Bob said:

The problem we have with narrowboats is that 2 pack epoxies dont always meet expectations for the hull coatings. Yes, 10-15 years performance is possible from epoxies but performance is badly compromised when you bend the rules. Epoxies work as a barrier coating ie when applied at the right thickness they reduce the permeation of water/oxygen to an low level and the excellent adhesion stops the coating 'lifting'/'undercutting' and allowing water/oxygen onto the steel surface. Any reduction in adhesion is going to reduce lifetime.

 

I spent 10 years managing a technical team developing surface tolerant epoxies for the oil industry (focussing first on splash zone coatings). Yes they work but they are a compromise.

 

All in all, it is impossible to get an epoxy to perform to 100% when needing surface tolerance and low temperature application so the 10-15 year target can be a dream. We worked on some very innovative routes to improved performance using the output of a huge research department and ended up knowing that painting with epoxy in the UK is restricted to a limited number of months a year if you want best performance. Maybe compromised performance is ok for narrowboats?

Nice to see solid and relevant technical information from somebody who really knows their stuff, not just anecdote or hearsay ?

 

P.S. Not in any way aimed at Daniel who also provided some very good information, thank you ?

Edited by IanD
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