Rust!

[Wiff]

I have a boat that was freshly painted with a rust inhibitor and a layer of grey primer last autumn by a boat yard. The paint is clearly rusting underneath and in places flaking off leaving raw rust patches, is this normal? I have been informed that I should have put a top coat on right away but I have painted other areas of the boat since in red oxide primer and no rust has re appeared.

 

I did intend to paint the boat in the sunny weather but now find i have to treat and re prime the whole of the roof before painting

 

I would like to know what your views are on this. Local boaters who have seen the job say it should not be flaking and bubbling rust.

 

Thanks

 

Heather

[pquinn]

I have a boat that was freshly painted with a rust inhibitor and a layer of grey primer last autumn by a boat yard. The paint is clearly rusting underneath and in places flaking off leaving raw rust patches, is this normal? I have been informed that I should have put a top coat on right away but I have painted other areas of the boat since in red oxide primer and no rust has re appeared.

 

I did intend to paint the boat in the sunny weather but now find i have to treat and re prime the whole of the roof before painting

 

I would like to know what your views are on this. Local boaters who have seen the job say it should not be flaking and bubbling rust.

 

Thanks

 

Heather

it sounds like a poorly prepared job.

[BEngo]

I have a boat that was freshly painted with a rust inhibitor and a layer of grey primer last autumn by a boat yard. The paint is clearly rusting underneath and in places flaking off leaving raw rust patches, is this normal? I have been informed that I should have put a top coat on right away but I have painted other areas of the boat since in red oxide primer and no rust has re appeared.

 

I did intend to paint the boat in the sunny weather but now find i have to treat and re prime the whole of the roof before painting

 

I would like to know what your views are on this. Local boaters who have seen the job say it should not be flaking and bubbling rust.

 

Thanks

 

Heather

Primer is porous. It was not exactly dry over the winter so the paint will have been letting water through to the steel. It is not at all surprising that there is rust coming through. You have to get a coat of undercoat or better, undercoats and gloss, on ASAP after primer and certainly before it rains on the primer. This provides a waterproof surface so the steel doesn't start rusting under the paint. Once it starts to rust the rust gets under the mill scale and spreads steadily.

 

Rust may not have appeared under your recent red-oxide but will. It's only a matter of time, even if you put some gloss over it.

 

For a proper job you now need to get the primer off, de-rust with abrasive sanding discs and wire brushes, apply Vactan or Fertan then put a full paint scheme on. Anything else will not last.

 

 

Sorry.

 

N

[Wiff]

so the £900 I spent on the job was totally wasted then, wonder why nobody informed me before i spent the cash!

[Grace and Favour]

so the £900 I spent on the job was totally wasted then, wonder why nobody informed me before i spent the cash!

Well unfortunately BEngo's correct - primer and undercoat are )microscopically( porous - and so rust is inevitable if left like this for any extended period of time - and particularly through winter!!!

 

Any half-decent painter should have told you that

 

However, you are best now to take the paintwork back to steel, and starting again. and do it either under cover (in a dry dock or poly-tunnel) or at least during an extended dry weather period (we can but hope)

[alan_fincher]

Primer is porous. It was not exactly dry over the winter so the paint will have been letting water through to the steel. It is not at all surprising that there is rust coming through. You have to get a coat of undercoat or better, undercoats and gloss, on ASAP after primer and certainly before it rains on the primer. This provides a waterproof surface so the steel doesn't start rusting under the paint. Once it starts to rust the rust gets under the mill scale and spreads steadily.

 

Rust may not have appeared under your recent red-oxide but will. It's only a matter of time, even if you put some gloss over it.

 

For a proper job you now need to get the primer off, de-rust with abrasive sanding discs and wire brushes, apply Vactan or Fertan then put a full paint scheme on. Anything else will not last.

 

 

Sorry.

 

N

What he said.

 

so the £900 I spent on the job was totally wasted then, wonder why nobody informed me before i spent the cash!

Well it might not have been, had you then followed it up quickly with more than primer.

 

Unless they told you the primer would provide a rust resisting waterproof layer to last a winter, (which I doubt), I don't think you can really be too upset with them.

 

They probably expected you to carry on with the next essential layers, but unfortunately you didn't realise you needed to get on with that straight away.

[ditchcrawler]

it sounds like a poorly prepared job.

Sounds like my roof. You didn't let the snow and rain fall on it, did you?

[bottle]

I have a boat that was freshly painted with a rust inhibitor and a layer of grey primer last autumn by a boat yard. The paint is clearly rusting underneath and in places flaking off leaving raw rust patches, is this normal? I have been informed that I should have put a top coat on right away but I have painted other areas of the boat since in red oxide primer and no rust has re appeared.

 

I did intend to paint the boat in the sunny weather but now find i have to treat and re prime the whole of the roof before painting

 

I would like to know what your views are on this. Local boaters who have seen the job say it should not be flaking and bubbling rust.

 

Thanks

 

Heather

 

Absolutely correct, sorry but as others have said, back to bare metal and start again.

[system 4-50]

You should have trawled this forum more thoroughly, earlier. The mantra is repeated over and over again.

Primer? Top coat it NOW NOW NOW.

Primer? Top coat it NOW NOW NOW.

Primer? Top coat it NOW NOW NOW.

Primer? Top coat it NOW NOW NOW.

Primer? Top coat it NOW NOW NOW.

[Wiff]

Shame it continuously rained till christmas then froze, just wish I had been better advised by those that take the cash. I did at one point want to take the boat in a rough state and do it myself and was advised against this as it would be better if they put on the primer. Feel quite disgusted a bad job done for me all round shall not go there again!

So if a coat of undercoat and not primer had been applied would I still have this problem?

[BEngo]

Undercoat alone, on bare steel, will blister and peel, then the steel goes rusty.

 

You need all three coats. Undercoat will not stick to steel unless it has primer on it. Crudely, the primer is built to stick to the steel; the best etch themselves into it. The undercoat bonds to the porous primer (it sort of 'soaks in'), then the top coat chemically bonds to the undercoat.

 

Undercoat is in many cases non-porous, but the ability of the top coat to form a chemical bond to the undercoats decreases quite fast as time passes. If you want to leave the boat in undercoat for any time then first get advice from your chosen paint maker's technicable bods. They will tell you whether their undercoat is porous and how long you can leave it before overcoating.

 

N