Painting the roof

[Looby Loo]

Hello,

 

Well the opportunity has finally come to tackle the roof. It was in a bad state when I bought my boat a couple of years ago and time has not improved it. I have searched for previous threads on this topic all of which had useful information but what I need is the idiot's guide on how to do it!

 

I am using an angle grinder with a wire brush attachment that strips the many previous paint layers off ok and works fine with the genny. I don't want to hire a scabbler as I will be tackling the roof in stages as and when weather, mooring location and lack of neighbours for the paint removal part permits. So once I have got the roof section I'm doing back to bare metal what then? There are some rust patches but the majority seems sound. I have seen products such as Vactan, Fertan and Owatrol mentioned but need guidance as to which is best suited and what to do with it. As you can tell I'm a complete novice so all advice will be gratefully received.

 

Many thanks

[Higgs]

A scabbler would obviously make light work of stripping the roof, but they really come into their own when tackling sand and very thick layers of paint. I would use an orbital sander, of the circular type and attached to a vacuum, using 80 grit to do the donkey work.

 

I'm not very keen on grinders to strip paint, they create loads of dust. Nor would I bother with Owatrol or the rust treatments. Wire brushes are useful, once you're down to the metal. Good for finishing around welds and pitting. Bad pitting, once clean, can be filled. Use a surface cleaner to degrease the steel.

 

Then all you need is primer, undercoat and topcoat. Not using Owatrol or the other products you mentioned, over years of painting boats, had no adverse effects. Good prep work and quick application of paint onto a clean and thoroughly degreased surface is all you need. I've seen plenty go wrong when people have used those additives as magic cure alls. Some people swear by them.

[Looby Loo]

Hi Higgs,

 

Thanks for the reply. You mentioned filling rust pits- with what? Can you give me guidance on what sort of filler to use please, and likewise for the surface cleanser... as I said-total novice!!

[David Schweizer]

If you manage to get the worst of the rust off, may I suggest you prime the roof with Rustoleum. Before it's re-paint, the roof of our boat was almost more rust than clean steel, the boat painter applied a couple of coats of Rustoleum primer, before the undercoat and top coat.

 

Rustoleum was a bit of an experiment for him, and he spent half a day at the factory to learn about the paint and it's properties, they assued him that a couple of good thick coats would prevent any remaining rust from emerging, and would protect any bare steel, apparently the paint is based on fish oil rather than mineral oi. It is now three years since the re-paint, and there is no sign of any rust coming through.

Edited August 7, 2015 by David Schweizer

[OldPeculier]

Do you really need to take all the paint off? You say it is sound except for a few rust patches. All I am doing is grinding out the rust, bringing those spots up to the paint level with body filler then sanding the whole lot down with an orbital sander ready for a couple of top coats.

 

If the paint is well stuck on, I say leave it and save yourself loads of work. Just my opinion....

[bizzard]

If you manage to get the worst of the rust off, may I suggest you prime the roof with Rustoleum. Before it's re-paint, the roof of our boat was almost more rust than clean steel, the boat painter applied a couple of coats of Rustoleum primer, before the undercoat and top coat.

 

Rustoleum was a bit of an experiment for him, and he spent half a day at the factory to learn about the paint and it's properties, they assued him that a couple of good thick coats would prevent any remaining rust from emerging, and would protect any bare steel, apparently the paint is based on fish oil rather than mineral oi. It is now three years since the re-paint, and there is no sign of any rust coming through.

Perhaps the rust didn't like the smell, has done a U turn and is now forcing its way out on the inside instead, up behind the ceiling.

[Higgs]

Hi Higgs,

 

Thanks for the reply. You mentioned filling rust pits- with what? Can you give me guidance on what sort of filler to use please, and likewise for the surface cleanser... as I said-total novice!!

 

 

In the past I have used Isopon P38 filler. What you're working on will not be submerged and a decent flexible filler is sufficient. Can get this from Halfords or a motor factors. Likewise the degreaser, from a motor factors. These places deal in car body products and paints. The degreaser will be quite volatile and evaporates very fast. If you aren't working in a well ventilated place, it would be worth getting a face mask - suitable for VOC's - Volatile Organic Compounds.

 

You will also need a packet of Tak rags for picking up dust prior to painting. A vacuum cleaner is invaluable for attaching to some pieces of equipment and for removing particles from the steel surface after the sanding. Vacuum and soft brush will remove the vast amount of dust particles.

Edited August 7, 2015 by Higgs

[Looby Loo]

Thanks for the tip about Rustoleum David. I will google it.

 

Old Peculiar- If I thought I could get away with it I would do just that, but the roof is a bit like Joseph's coat of many colours now. There is so much paint flaking off all over the place I feel happier just getting shot of the lot and starting from scratch. Yes - a lot more work, but hopefully it won't need to be done again in the near future once completed. The roof is sound- ie no rust but the paint is lifting on a daily basis, despite having had one good going over to remove the loose stuff so I could see what I was left with.

[Higgs]

Thanks for the tip about Rustoleum David. I will google it.

 

Old Peculiar- If I thought I could get away with it I would do just that, but the roof is a bit like Joseph's coat of many colours now. There is so much paint flaking off all over the place I feel happier just getting shot of the lot and starting from scratch. Yes - a lot more work, but hopefully it won't need to be done again in the near future once completed. The roof is sound- ie no rust but the paint is lifting on a daily basis, despite having had one good going over to remove the loose stuff so I could see what I was left with.

 

 

Loose stuff is what you get frequently after painting and not prepping thoroughly.

 

Nothing to do with your boat, but I would be slightly suspicious of a boat that had been touched up prior to a sale. I wouldn't expect the paint to be completely sound.

Edited August 7, 2015 by Higgs

[Looby Loo]

The previous owner was a demon with the DIY- unfortunately not very well to put it mildly! The boat had more tins of paint on it than B&Q and about as many brushes and rollers! He was more into slapping it all over with probably little prep work. There is more of the original red on the front deck visible now than the raddle red he painted over it which has largely come off. The anti-slip gritting consists of clumps rather than an even spread.The rusty bits weren't touched up when I bought it, but fully visible. The kindest thing that can be said about the state of the paintwork is that it has character The boat was fully surveyed prior to purchase btw. I'm currently saving up for a decent paint job on the sides, done by a professional, although it may end up being more than the sides if I make a dog's dinner out of the roof

The interior is in need of some TLC too (complete bathroom refit for starters) but that is cosmetic so less of a priority for the budget.

 

Thanks for your help with this. I used to do all the decorating when I had a house, so know that proper preparation is crucial but this will be my first attempt on my boat, hence all the questions.