Blackening on top of primer

[Elias Harwood]

Can I paint blackening onto keyed primer?

I want to paint it below the gunwales to the bottom of the first rubbing strake so it’s not going near the water line. I’m going to use a two pack epoxy for everything below the first rubbing strake.

Thank you,

elias

[rusty69]

Sure you can. Whether it will adhere well is another question. Read the tin and the data sheets if you can. Some blacking products prefer to go on bare steel or previous applied blacking (of a similar type). What is there at present?

 

ETA, I always use gloss paint on the bit down from the gunwales.

Edited October 26, 2018 by rusty69

[pearley]

SML Coatings advised us to use Vinyguard primer before applying their blacking. Sticks sell. 

[Elias Harwood]

1 hour ago, rusty69 said:

Sure you can. Whether it will adhere well is another question. Read the tin and the data sheets if you can. Some blacking products prefer to go on bare steel or previous applied blacking (of a similar type). What is there at present?

 

ETA, I always use gloss paint on the bit down from the gunwales.

Hi Rusty,

Old primer.

I normally use gloss too. But this way any damage caused, and it’s mostly below the gunwales, can be easily fixed by painting on more blackening. Otherwise it’s sanding, converting, priming, painting. Someone told me this was common practice on the old working boats.

 Thanks

[Elias Harwood]

21 minutes ago, pearley said:

SML Coatings advised us to use Vinyguard primer before applying their blacking. Sticks sell. 

Thank you Pearley

[blackrose]

3 hours ago, pearley said:

SML Coatings advised us to use Vinyguard primer before applying their blacking. Sticks sell. 

Jotun Vinyguard is good and so is International Primocon - I think it's the same stuff - looks the same anyway.

[Elias Harwood]

Thank you 

[Elias Harwood]

I received a message concerning my question about using Rylard Premium Protection- Bitumen Coating With Gilsonite on top of keyed primer from boatpaint.co.uk and was told “ 

Yes – that would be fine. It is a spirit-based product – so no fear of damage to the primer.

Above the waterline is fine”.

Thanks all,

elias

 

[blackrose]

I think the thing to do is also key the surface prior to applying the primer. 

 

In general if you apply subsequent coats soon after previous ones you don't need to key them because (assuming the paints are compatible) you will have good molecular bonding. It's only after coats of paint have been left for some time that keying is required. That is unless you're after the perfect finish, in which case you should rub down between every coat.

Edited October 26, 2018 by blackrose

[Dr Bob]

Good advice above from Rusty and Blackrose but suggest you dont paint it this weekend! Far too cold. Dont try and paint if the temp is near the dew point - always try and be 3 or 4°C above - otherwise you will have condensation on the blacking will not stick. Look for the dew point on various web sites such as xcweather.co.uk. Unless you have a heated paint shop, I would wait until April now. Paints with solvents dont like average temps below 15°C. You can get away with low temp epoxies but I wouldnt. Too much of a compromise.

[Elias Harwood]

Hi guys.

I know it’s  late in the year and I really don’t want to blacken my boat now but I really have no choice.

Just ordered the blackening so it won’t be this weekend, Thursday is looking good weather wise.

I use Accuweather which gives comprehensive information on the weather.

I will of course key the primer and use actetate to clean bare steel or remove grease. And I will convert any rust patches.

Thank you for the advice,

elias

 

[Richard10002]

6 hours ago, Elias Harwood said:

Hi guys.

I know it’s  late in the year and I really don’t want to blacken my boat now but I really have no choice.

Just ordered the blackening so it won’t be this weekend, Thursday is looking good weather wise.

I use Accuweather which gives comprehensive information on the weather.

I will of course key the primer and use actetate to clean bare steel or remove grease. And I will convert any rust patches.

Thank you for the advice,

elias

 

Why do you have no choice? The boat won’t come to much harm between now and March/April.... compared to the poor quality of the job if the world is damp when you do it next week.

[KenK]

I had my boat blacked last November supposedly in a heated dry dock. I've just done it again. The blacking fell off in patches, all over the sides above the waterline throughout the summer and when we took it out of the water all of the blacking below the waterline had gone leaving a thin white powder coating, below that it was bare metal. It is likely that the boat was blacked when it was damp and this caused the lack of adhesion. I have complained to the company concerned and sent a variety of photographs showing the condition of the boat, I wonder what their response will be!

 

Ken

[Dr Bob]

1 hour ago, KenK said:

I had my boat blacked last November supposedly in a heated dry dock. I've just done it again. The blacking fell off in patches, all over the sides above the waterline throughout the summer and when we took it out of the water all of the blacking below the waterline had gone leaving a thin white powder coating, below that it was bare metal. It is likely that the boat was blacked when it was damp and this caused the lack of adhesion. I have complained to the company concerned and sent a variety of photographs showing the condition of the boat, I wonder what their response will be!

 

Ken

Let us know how you get on.