Priming a hull before blacking?

[Ben Wilson]

Hi guys, 

 

I am doing some work on my Springer Waterbug and am going to be taking the hull back to bare metal before welding, and eventually new blacking. To be on the safe side I'd like to use some sort of metal primer/rustproofing paint prior to blacking the hull, but am unsure what to go for, or even how necessary it is. 

 

Can anyone offer advice or any recommendations? 

 

All the best

[blackrose]

You can paint the blacking straight onto bare steel. However, if you want to use a primer then make sure it's a primer suitable for underwater applications: International Primocon or Jotun Vinyguard are two that I've used and they're virtually identical products. Quick drying and a couple of coats will give you about an extra year on top of the lifespan of the bitumen.

 

How are you getting it all back to bare steel? I have to say, if I was going to all the trouble of taking a hull back to bare metal I'd be painting it with a good 2 part epoxy - for example, Jotamastic 90 (winter grade). 3 or 4 coats of that properly applied according to the technical data sheet should give you up to 10 years service life (no primer should be used).

 

Epoxy is a more technical product to mix and apply than single part paints, so if you're not confident stick to underwater primer and bitumen.

Edited May 16, 2023 by blackrose

[Ben Wilson]

Thank you very much, that's a big help. I'm taking it back to bare metal largely because of welding to be done on the side plates, but also because the blacking previously is very patchy (it was neglected a bit with it's previous owners sadly).

 

I've been using mostly a 4 inch scraper and then an angle grinder/drill with a brush attachment which has so far been working really nicely. 

 

2 part epoxy could be an option, I'm a bit guided by price though so bitumen may be the best bet. 

 

Thanks again!