Preparing to paint a steel boat

[Rustic Charm]

Originally Posted by Russ

Have owned steel for 15 years. NOT blasting a BIG mistake on an old boat. Skip the fairing, spend the money on a good blast and use AMERON paint. Joint the Metal Boat Society they have loads of info. I use AMERON Primer and then AMERON on deck but Interlux for topsides ( a bit more shine then athe AMERON which gets pretty flat.

Thanks Russ, but for the reason's I've already posted, sandblasting is not an option. Thus, I need to do the next best thing.

[Rustic Charm]

Has anyone ever tried Topflight by Norglass?

It's a non ablative hard antifoul heavily impregnated with copper, but it's a single pac.. A bit expensive at $82 a litre, but no where near as expensive as the $200 a litre for coppercoat.

[ThresherMan]

You might want to check out the articles here:

How to maintain and operate your Boat!

[conachair]

This is well worth a few dollars for a download, imho

http://www.amazon.com/Metal-boat-mai.../dp/B0070QRME4

Another vote for ameron sealer when you can't blast.

[ski69sail]

Hi there, I have just done a lot of painting on my steel yacht. Altex paints make a commercial product called Carbogard . They also have a distributor in Tassie and I would recommend having a chat with them. I can also put you in touch with the local rep here in New Zealand if you do not get all your questions answered.

[Wotname]

Originally Posted by Snowpetrel

...
Underwater is always an interesting juggle. If the paint isn't falling off in big chucks I'd just cross my fingers and repaint with good quality compatable antifouling. I'd be reluctant to put coppercoat over an old substrate, and it's a huge job to strip all the old antifouling back without a sandblaster. done it the hard way now on three boats.

+1, especially about caution using coppercoat over existing AF coatings. While I'm very happy with my coppercoat (7 years IIRC), I did start with a clean slate. FWIW, I initially allocated 3 days to remove 30 years of AF on a 30 footer; in fact it took almost 6 weeks.

[Rustic Charm]

Originally Posted by Wotname

+1, especially about caution using coppercoat over existing AF coatings. While I'm very happy with my coppercoat (7 years IIRC), I did start with a clean slate. FWIW, I initially allocated 3 days to remove 30 years of AF on a 30 footer; in fact it took almost 6 weeks.

6 weeks?

What were you using to remove it with? A butter knife

I'm intending to use 'Peelaway'. It's meant to be pretty good in removing 'paint' and is said to easily remove AF's

[Truemettle]

Rustic Charm, I guess International Paints do not live up to their name. I am trying to see the humour in this!

[Triumphant]

I have owed a steel boat for over 20 years and tried lots of methods and we have just been through the 6 month refit and re plating exercise in Rio Dulce Guatemala.

Our current solution for rusty steel preparation if you cannot blast is as follows:

We use chipping hammers, grinders and then stainless steel wire brushes on power tools, both brushes and wheel types to prepare the areas that were corroded until they were shiny, wash the area with water and degrease then painted on Phosphoric acid and leave overnight.

if the steel still has black spots on it in the morning, this means that rust is still present, do it again until there are none.

If the steel was still shiny in the morning with no black pitting then you go ahead and wash it in water (the phosphoric acid leaves some kind of barrier coat like Ospho which stops rusting) then apply 2 to 3 coats of a good quality 2 pack primer, this time we used International 2 pack which is getting good reports from the contractors in the area on a variety of materials.

Depending on the paints and the timing, you may have to sand the primer to provide a mechanical key. Other paints are applied before the primer is fully cured to provide a chemical key, check this out first.

After that, 2 to 4 coats on the top sides of a good quality 2 pack epoxy top coat.

Below the waterline, 2 coats of Coal tar epoxy over the primer as a barrier coat then 2 to 4 coats of antifouling.

We use Transocean paints here as they are available, they work, they are designed for commercial ships and they are cheaper than US products.

We do not bother with fairing compounds below the water line as you cannot see it and if you want to do NDT (Non Destructive Testing) in the future to find thin spots in the steel this causes problems.

I am not sure about using Copper coat on a steel boat, sound a bit scary


Hints
Do not use normal steel wire brushes as they spray wire everywhere which ends causing more rust

Do not be afraid to use lots of water to wash away grinding debris and other contaminates

Use Degreasing products on bare steel

Do not bother with Ospho as it is very expensive, here it is about 8 times the cost of Phosphoric acid which is one of it’s main ingredient and you can control the strength of the solution better. It is sold here in all the paint shops.

Good luck

[Rustic Charm]

Originally Posted by Truemettle

Rustic Charm, I guess International Paints do not live up to their name. I am trying to see the humour in this!

Truemettle, you have completely lost me with your comment?

Why do International Paints not live up to their name?

What is so humerous?

[Rustic Charm]

Originally Posted by Triumphant

I have owed a steel boat for over 20 years and tried lots of methods and we have just been through the 6 month refit and re plating exercise in Rio Dulce Guatemala.

Our current solution for rusty steel preparation if you cannot blast is as follows:

We use chipping hammers, grinders and then stainless steel wire brushes on power tools, both brushes and wheel types to prepare the areas that were corroded until they were shiny, wash the area with water and degrease then painted on Phosphoric acid and leave overnight.

if the steel still has black spots on it in the morning, this means that rust is still present, do it again until there are none.

If the steel was still shiny in the morning with no black pitting then you go ahead and wash it in water (the phosphoric acid leaves some kind of barrier coat like Ospho which stops rusting) then apply 2 to 3 coats of a good quality 2 pack primer, this time we used International 2 pack which is getting good reports from the contractors in the area on a variety of materials.

Depending on the paints and the timing, you may have to sand the primer to provide a mechanical key. Other paints are applied before the primer is fully cured to provide a chemical key, check this out first.

After that, 2 to 4 coats on the top sides of a good quality 2 pack epoxy top coat.

Below the waterline, 2 coats of Coal tar epoxy over the primer as a barrier coat then 2 to 4 coats of antifouling.

We use Transocean paints here as they are available, they work, they are designed for commercial ships and they are cheaper than US products.

We do not bother with fairing compounds below the water line as you cannot see it and if you want to do NDT (Non Destructive Testing) in the future to find thin spots in the steel this causes problems.

I am not sure about using Copper coat on a steel boat, sound a bit scary


Hints
Do not use normal steel wire brushes as they spray wire everywhere which ends causing more rust

Do not be afraid to use lots of water to wash away grinding debris and other contaminates

Use Degreasing products on bare steel

Do not bother with Ospho as it is very expensive, here it is about 8 times the cost of Phosphoric acid which is one of it’s main ingredient and you can control the strength of the solution better. It is sold here in all the paint shops.

Good luck

Thank you Triumphant, very useful hints.

I was conscious of coal tars being used on marine structures but didn't think of it on a boat.

And very helpful hint about not using normal steel wire brushes. I think a bit of that happened to me last year when I did the deck.

[Truemettle]

It lost something in the translation, International Paints is not available in Austrailia, that does not strike me as being too international. Just a bad joke getting worse with an explaination. :-)

[Snowpetrel]

Originally Posted by Rustic Charm

6 weeks?

What were you using to remove it with? A butter knife

I'm intending to use 'Peelaway'. It's meant to be pretty good in removing 'paint' and is said to easily remove AF's

Took me about 6 weeks more or less full time, on the last two boats but with a few extra jobs happening as well, and a few R&R days. Though I didn't use any paint stripper, which may, or may not help.. so I'll be interested to hear how it goes for you. What sort of cost was the paint stripper?

Anyway what I did last time on my alloy yacht, was scrape, sand and curse all the antifouling off, becouse it was loose in a few places, unfortunately it had stuck like s$%t to a blanket in the rest! Then I bogged the modifications and bare alloy areas, after sanding and priming. Then sanded the whole bottom with 8 inch (or so) 40 grit disks on a Makita polisher/sander. Then I put three coats of wattle epoxy primer over the whole boat underwater, very lightly sanding between to take off any lumps. I followed this with a coat of the wattle two pack tie coat, then two coats of antifouling. Hopefully it's going to work for many years, with fresh antifoul every year or so.

I didn't do the topsides (next!), but if I did I would have measured from the sheer to the waterline carefully first, and sanded and faired the topsides at the same time, and painted them with the same primer while painting the hull, then just masked and painted on the polyurethane with a roller. Don't go high gloss on a poorly faired boat , it looks terrible. Add some flattening powder and roll it on.

Compatability of the old topsides paint might be an issue. Either sand it all off, or do a test. Often a high solids epoxy can go over old single pack. Not perfect but it works. Invest in some good protection. A full face mask us worth its weight in gold. A festol Sander with vac is a brilliant but if kit as well. Good Scaffolds really help.

I'd buy the epoxy paint by the 20 litre drum, and just keep putting on coats till it's all gone. Say 4 full coats would be ideal. I would fair underwater, if it needed it. Males it much easier to repaint and sand if it's moderately smooth.

Sent from my HTC_0PCV2 using Cruisers Sailing Forum mobile app

[Rustic Charm]

Originally Posted by Truemettle

It lost something in the translation, International Paints is not available in Austrailia, that does not strike me as being too international. Just a bad joke getting worse with an explaination. :-)

International is available in Australia, just not the two products earlier stated.

[Wotname]

Originally Posted by Rustic Charm

Thank you Triumphant, very useful hints.

I was conscious of coal tars being used on marine structures but didn't think of it on a boat.

And very helpful hint about not using normal steel wire brushes. I think a bit of that happened to me last year when I did the deck.

AFAIK, tar epoxy is no longer permitted on recreational boats in Oz. Has been banned for some years now.