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Steel Hull Repair

BJP_1

New member
Joined
21 Nov 2020
Messages
1
HI All,

I'm looking at the best ways to remedy the rusty areas on my steel hulled yacht.

As far as I can tell there are two ways to do this.

The first and cheapest way seems to be to use an angle grinder with a steel wire brush attachment to grind away the problem areas and then prime and repaint.

The second and more expensive is to get the hull sand blasted.

I am on a tight budget so using the first approach seems to make the most sense to me.

I was wondering if anyone has any suggestions or past experience.

Thanks,

Joe
 

NormanS

Well-known member
Joined
10 Nov 2008
Messages
7,772
I'm sure you're on the right lines there. Is the rust inside or outside? If inside, practically impossible to sand blast, and if outside, it's not worth it unless the whole hull needs to be done, so you're back to the electric wire brush.
Don't know where you are, but if outside in the UK, this is not a good time to expose bare steel to the weather. You want dry air, and as soon as an area is prepared, slap the primer on.
You'll probably get more, but not necessarily better, advice on the PBO forum.
 

Whitlock

Member
Joined
17 Nov 2020
Messages
53
If the rust is severe enough to require a wheel I would suggest that you have a hull survey to check that there is still sufficient thickness of steel there.
Going at it with a wheel will get the rust off but, depending on the age of the boat, it's comforting to know that you're not grinding too much away.
My boat is steel 10mm thickness below the waterline and only 14 years old but I took the opportunity this year to have an ultrasound survey while it was out of the water to prove that it was all OK, which it was. A friend, on the other hand, was digging out rust inside the anchor locker of his steel boat and went right through the hull.
 

Wansworth

Well-known member
Joined
8 May 2003
Messages
16,692
Location
SPAIN,Galicia
as mentioned not best time to do painting ,give it a wire brush and slap on some primer to keep it till the warmer weather
 

srm

Well-known member
Joined
16 May 2004
Messages
1,280
Location
Azores, Terceira.
There is a saying that steel hulls rust away from the inside. My experience confirms this; most of the exterior epoxy coating looked good after over ten years hard use however I eventually managed to sell the boat for its scrap value. The buyer stripped the interior to the bare hull and replated all suspect areas then shot blasted and painted inside and out!

I was advised by a competent surveyor (sadly they seem to be a minority in the trade these days) that cleaning and recoating the visible rusty patches is not effective as corrosion is probably going on under the old coatings. Each year you will be finding more places to clean and paint.

As suggested above power wire brush, or better a needle gun, and primer as a temporary holding treatment, but if you want to keep the boat full grit blasting and appropriate coatings in a dry environment is the only effective way - but its going to be expensive.

Incidentally, a wire brush in an angle grinder is not all that effective at removing rust, it tends to burnish giving a dark surface. I used a coarse abrasive sanding disk as that could shift paint and rust to get down to bright metal. But, be careful how much metal you remove!
 

Wansworth

Well-known member
Joined
8 May 2003
Messages
16,692
Location
SPAIN,Galicia
Working on rusty old Dutch coasters a pen knife was always useful in attacking a bit of rust or flaking paint,a sort of therapy,anyway kept a brush with red primer handy and so we kept on top of the “rust”🤣
 
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