Steel hull, How clean does it need to be before painting?

[fodder1]

Hi Everyone,


So I recently brought a Admas40 that was very cheap. The owner was very upfront and showed me all the faults. One of the major ones was the bottom was very heavily fouled. While cleaning and preparing the boat to get it back closer to home I dived the hull and to say it was heavily fouled would have a been HUGE understatement. When I cleaned it off it took off a lot of the paint down to the steel. As you could imagine this means that i will need to strip and re-paint.



After doing a lot of reading, I understand the hull need to be cleaned of rust, then primed (normally epoxy, currently has PPG simgacover280) the covered in a top coat of epoxy (ppg sigmadua550) then the ablative antifoul.


A bit more reading, you need to get the hull back to "clean metal" or "white Metal" which after a bit of trial and error with some different disks and an angle grinder seems to be an impossibility. As the steel is still a little 'orange peel' and the pits of that orange peel still have rust.


I wondered if I could just wash the steel with some rust converter, but when I read the directions it states "do not use with high zinc primers".


So without sandblasting, I dont think I can get it back to "white metal"



Then after a bit more reading, I found the "needle gun". But from the videos I have watched the needle gun gives the steel a hammered look. Also the videos don't really bring back the steel to "white metal". IE the steel is still showing the darker color and rust colour. A good option for DIY to get the pannels clean.



At nearly 5K for my boat to be blasted fron the water line down, including interlux primer, so I am looking for options.


As for the Needle gun, I was wondering at the noise level.



Chris.

[Panope]

5K for blast and prime sounds like a bargain. It is the only sensible option.

Steve

[stainless guy]

Save your money on the needle gun and put it towards doing it right. Blast to white and start over