Tidying up minor scrapes

[AndyE]

The boat's relatively new. The hull has 2-pack epoxy blacking over a very pale undercoat.

 

In places, whilst learning the boat's handling, I've collected a few scrapes (I say this somewhat sheepishly), leaving the undercoat shining brightly through.

 

I've previously been told that you can't patch up 2-pack with black paint. This leaves me wondering how I might tidy up the scrapes?

 

Any help much appreciated.

[Tony Brooks]

4 minutes ago, AndyE said:

The boat's relatively new. The hull has 2-pack epoxy blacking over a very pale undercoat.

 

In places, whilst learning the boat's handling, I've collected a few scrapes (I say this somewhat sheepishly), leaving the undercoat shining brightly through.

 

I've previously been told that you can't patch up 2-pack with black paint. This leaves me wondering how I might tidy up the scrapes?

 

Any help much appreciated.

 

You probably can, but how it might affect subsequent coats of epoxy is open to question. I know it's a faff, what with mixing etc, but probably best to rub down a bit and touch up with more epoxy.

[BEngo]

Just wire brush it, ideally with an angle grinder and put some epoxy on top.  You will need to measure the epoxy carefully to get the proportions right, as you won't  want a full can.

 

N

[ditchcrawler]

I just don't bother. Mine was scuffed before I got back to my home mooring after the last blacking

[AndyE]

 

7 minutes ago, ditchcrawler said:

I just don't bother. Mine was scuffed before I got back to my home mooring after the last blacking

Fair comment... I may well reach the same conclusion. It's just that the undercoat is such a stark contrast to the blacking.

8 minutes ago, BEngo said:

Just wire brush it, ideally with an angle grinder and put some epoxy on top.  You will need to measure the epoxy carefully to get the proportions right, as you won't  want a full can.

 

N

Hmmm... angle grinder sounds quite heavy duty. Or maybe I'm imagining the wrong type of tool! Any recommendations for tools & re-coating products appreciated!

12 minutes ago, Tony Brooks said:

 

You probably can, but how it might affect subsequent coats of epoxy is open to question. I know it's a faff, what with mixing etc, but probably best to rub down a bit and touch up with more epoxy.

Thanks Tony. So, strip back to bare metal and then touch up with more epoxy presumably using sand/emery paper? Can I ask what primer/undercoat is required? And, can you suggest a product that would be appropriate for small-scale epoxy touch-up? Thanks again.

Edited July 23, 2023 by AndyE

[Mike Hurley]

3 minutes ago, AndyE said:

Thanks Tony. So, strip back to bare metal and then touch up with more epoxy presumably using sand/emery paper? Can I ask what primer/undercoat is required? And, can you suggest a product that would be appropriate for small-scale epoxy touch-up? Thanks again.

As the boat is relatively new why not try to contact the builder and ask what 2 pack epoxy they used, you may be able to buy the same stuff avoiding any compatibility issues.

[BWM]

There are some resin based paints that will likely do the job, and not affect the next epoxy coat. 

[blackrose]

42 minutes ago, AndyE said:

 

 

Thanks Tony. So, strip back to bare metal and then touch up with more epoxy presumably using sand/emery paper? Can I ask what primer/undercoat is required? And, can you suggest a product that would be appropriate for small-scale epoxy touch-up? Thanks again.

 

No don't take it back to bare metal, just go over the scrapes and areas immediately around the scrapes with some medium grit sandpaper to give it a key and then apply more of the same epoxy.

 

I don't know why your hull is undercoated because epoxy doesn't require undercoat. Perhaps it's a different colour of the same epoxy which was used to differentiate coats of paint. I've done that with my boat, using different shades of Jotamastic to enable me to see where I've painted.

 

If the scrapes have gone though to the steel and start to rust your sandpaper should still be ok unless the rust gets really bad in which case angle grinder with a wire wheel or cup.

[Tony Brooks]

1 hour ago, AndyE said:

Thanks Tony. So, strip back to bare metal and then touch up with more epoxy presumably using sand/emery paper? Can I ask what primer/undercoat is required? And, can you suggest a product that would be appropriate for small-scale epoxy touch-up? Thanks again.

Edited 1 hour ago by AndyE

 

No, just as Blackrose says. I would use wet & dry paper if there is no rust, probably about 300 grit. The same product as the builder used and once you know discuss it with the paint maker for exact advice.

[Feeby100]

There should not be undercoat then epoxy 

that wrong 

[ditchcrawler]

1 minute ago, Feeby100 said:

There should not be undercoat then epoxy 

that wrong 

When I worked Offshore the paint system was 2pk Zink high build primer on blasted steel and the coloured 2 pk

[blackrose]

Well we're all guessing. The only thing to do is for the OP to speak to the builder and find out what epoxy was used, how many coats, whether an undercoat was used and if so what it was. 

 

As this is a relatively new boat, why that isn't stated in an owner's manual is ridiculous in my opinion. My boat was a self-fitout and I've written down everything I've done including hull painting.

Edited July 23, 2023 by blackrose

[MtB]

3 hours ago, ditchcrawler said:

I just don't bother. Mine was scuffed before I got back to my home mooring after the last blacking

 

 

Same here. 

 

I like my boats to look as though they are used.

 

Sometimes I overdo it...

 

 

 

[LadyG]

The boat could come out of the water if it is to keep everything smart. I know my epoxy two or three years ago has faded badly. And if I could get it out I'd do a quick brass wire brush, a re epoxy then a coat of Hardtop. If only I'd known then what I know now.!

I am forever painting and take advantage of any resources available, but at the end of the day, a selection of sandpaper,  paints, brushes, rollers is at hand whenever the weather is suitable. 

Edited July 23, 2023 by LadyG

[blackrose]

49 minutes ago, LadyG said:

 I know my epoxy two or three years ago has faded badly. And if I could get it out I'd do a quick brass wire brush, a re epoxy then a coat of Hardtop. If only I'd known then what I know now.!

 

Chalking of epoxy is normal and doesn't affect its other properties. Is a black hull really so important to you? I'm perfectly happy with a grey hull. 

Edited July 23, 2023 by blackrose

[AndyE]

9 hours ago, LadyG said:

The boat could come out of the water if it is to keep everything smart. I know my epoxy two or three years ago has faded badly. And if I could get it out I'd do a quick brass wire brush, a re epoxy then a coat of Hardtop. If only I'd known then what I know now.!

I am forever painting and take advantage of any resources available, but at the end of the day, a selection of sandpaper,  paints, brushes, rollers is at hand whenever the weather is suitable. 

Would you mind explaining a couple of terms "re epoxy" & "Hardtop"? And what if the scrapes are above the waterline? Still out of the water?

8 hours ago, blackrose said:

 

Chalking of epoxy is normal and doesn't affect its other properties. Is a black hull really so important to you? I'm perfectly happy with a grey hull. 

Sorry for the noob question but what do you mean by "Chalking"? Grey would be OK but shiny white glaring out from under the black is a bit too striking (to my eye). I may get used to it. Right now I'm embarrassed of such clear evidence of my mistakes e.g.entering tricky locks. (I guess imposter syndrome into such a friendly but skilled community). 

[David Mack]

17 minutes ago, AndyE said:

Would you mind explaining a couple of terms "re epoxy" & "Hardtop"? And what if the scrapes are above the waterline? Still out of the water?

"Re epoxy" just means recoating with 2 part epoxy paint. And I assume @LadyG is referring to Jotun Hardtop AX, which is a 2 part polyurethane topcoat which can be used over epoxy, and won't go grey.

https://www.smlmarinepaints.co.uk/products/hardtop-ax

Scrapes above the waterline can be redone while the boat is afloat. If you are working close to the waterline you might want to heel the boat over a bit to get the area far enough out of the water to dry properly before painting (and until the paint has hardened).

 

Edited July 24, 2023 by David Mack

[LadyG]

8 hours ago, blackrose said:

 

Chalking of epoxy is normal and doesn't affect its other properties. Is a black hull really so important to you? I'm perfectly happy with a grey hull. 

Yes but it's not a nice even grey any more, it's sorts of grey brown on the waterline.

[David Mack]

17 minutes ago, AndyE said:

Sorry for the noob question but what do you mean by "Chalking"?

Black (and some other colours, notably reds), can go lighter coloured with time and weathering. So your black hull becomes grey. Some people are fine with this, others less so. But any patched areas will show up as black on grey, until they too have faded a bit.

[rusty69]

Having just done our boat, the first coat was grey, followed by red tinted, followed by black (for the reasons blackrose mentions). It made the actual painting process much easier than just using black. In hindsight, I think I prefer the grey to the black. 

 

Black may be traditional for a boat hull, mainly due to the limited products available in the past, but now other options are available, offering better levels of protection, I suspect we will be seeing more grey out there. 

[David Mack]

14 hours ago, BEngo said:

Just wire brush it, ideally with an angle grinder and put some epoxy on top.  You will need to measure the epoxy carefully to get the proportions right, as you won't  want a full can.

 

N

SML produce a chart showing the weights of the 2 components required for mixing up various quantities of Jotun paints. I use a cheap set of digital kitchen scales (£5 from Asda) to weigh the components out.

https://www.smlmarinepaints.co.uk/uploads/files/library/files/2 pack weights 0314.pdf

[Machpoint005]

I thought the main point of epoxy was that it didn't need doing every 2-3 years. Traditional blacking lasts that long, so in general, why not go for the less expensive option? After all, it's the haul/lift out that costs anyway.

 

 

[MtB]

3 minutes ago, David Mack said:

Black (and some other colours, notably reds), can go lighter coloured with time and weathering. So your black hull becomes grey. Some people are fine with this, others less so. But any patched areas will show up as black on grey, until they too have faded a bit.

 

I've always understood 'chalking' to be the process where old paint begins to break down and the surface becomes loose and powdery. The white paint in the lettering on my last boat did this. In the rain there would be white streaks running down to the gunwale from all the letters. 

 

The tendency for dark finishes to lighten with sun exposure is a different effect and should be called, in my opinion, "lightening". 

[rusty69]

2 minutes ago, David Mack said:

SML produce a chart showing the weights of the 2 components required for mixing up various quantities of Jotun paints. I use a cheap set of digital kitchen scales (£5 from Asda) to weigh the components out.

https://www.smlmarinepaints.co.uk/uploads/files/library/files/2 pack weights 0314.pdf

Mixing small batches straight from the tin is quite difficult though, or at least that is what I found trying to mix a small batch. Most of mine ended up on my shiny new scales on the first attempt, after which I used a small jug. 

Edited July 24, 2023 by rusty69

[David Mack]

Just now, MtB said:

 

I've always understood 'chalking' to be the process where old paint begins to break down and the surface becomes loose and powdery. The white paint in the lettering on my last boat did this. In the rain there would be white streaks running down to the gunwale from all the letters. 

 

The tendency for dark finishes to lighten with sun exposure is a different effect and should be called, in my opinion, "lightening". 

You may be right that there are two different processes going on, but I think 'chalking' is often used to describe both.