Paint quantities when blacking and ideas on general prep.

[Mattlr89]

Hi, 

I'm sure this has been covered ad nauseam, but is someone able to recommend approx. paint quantities when blacking as well as the best ways to prep the metal?

 

Here are my thought's so far...

 

I'm planning on doing a bottom coat of Rylards Premium Protection, then a middle coat of Rytex and finally a another coat of Premium Protection along the waterline. 

 

How much of each product would you recommend for a 70ft narrowboat?

 

Is it also recommended to use thinners with the initial coat, so that the paint fills pitted areas better?

 

When it comes to preparation, I plan to pressure wash, paint scrap and use a tungsten sanding disc on an angle grinder to prepare the metal before painting. 

 

Thanks in advance,!

 

Matt

[blackrose]

I never found rylards premium protection any better than any other Bitumen paint in terms of protection. It's just as susceptible to UV degradation and diesel on the waterline.

 

Personally I wouldn't use a sanding disc on an angle grinder anywhere on the hull below the waterline because you'll be taking off good steel too. Use wire wheels and eye protection and don't worry about the prep or the painting too much because any Bitumen blacking is only going to last a few years anyway.

[David Mack]

I used Ballistic Black, which claims to have a higher solids content than other bitumen paints.

Manufacturers data sheets give coverage rates from which you can work out the quantity required.

Surface prepped using a twisted knot wire cup brush on an angle grinder. Wire brush will get into the corners around welds etc. where a disc can't.

Edited June 27, 2021 by David Mack

[Sea Dog]

3 hours ago, Mattlr89 said:

Is it also recommended to use thinners with the initial coat, so that the paint fills pitted areas better?

You won't need to with Premium, it's already that bit "runnier" making it a good choice in that Rytex sandwich you are using it as the bread for!

 

At 57' I found about 4.5 litres of Premium and closer to 5 litres of Rytex did a full coat. Clearly, you're gonna need more - probably enough to end up with a most of a tin of each left!

 

I'd go the full 3 coats rather than coat 3 being waterline only. After that, slap some of the spare Premium on the waterline.

[Mattlr89]

Thanks all - really useful responses ?