Verdigris or dirty pipe turned white paint blue?

JamesA · 10 Nov 2006

Our plumber recently replaced some copper piping.
The new stuff was bare copper whereas the rest he joined to was painted white.
I therefore painted the new bits with Dulux satin paint for wood and radiators.
Its turned from white to sky blue and is flaking in places.
The pipe had black bits on the end where he'd used the blowtorch when joining.

Dulux said:
The colour change and flaking can be caused by Verdigris on the pipes. This is a whitish/green mould type of substance on the pipes. To ensure this does not happen again you will need to clean the pipes with white spirit then file down with wire wool. Once this process is complete wash with water then ensure pipes are clean and dry. Now you will need to apply a primer, we recommend Hammerite Special Metals Primer then once this is dry you will be able to apply the top coat.

Are they right?
Would the Verdigris have been visible as the pipes looking sparkling clean?

Yarn · 10 Nov 2006

Im no expert, but i think that you would have seen the Verdigris. I imagine that brand new pipe is as clean as the end of the cleaning process that they describe anyway.

How quickley did the pipe turn blue? Does the pipe get hot? Does the pipe attract condensation? Was the paint new well looked after paint?

breezer · 10 Nov 2006

pipe probably had flux residue, on it, stip it and clean it then paint it

JamesA · 10 Nov 2006

Yarn said:
How quickley did the pipe turn blue?

A few hours, as soon as it dried

Yarn said:
Does the pipe get hot?

No.

Yarn said:
Does the pipe attract condensation?

No.

Yarn said:
Was the paint new well looked after paint?

The paint is at least 3 months old, but I've used it on the wood cladding successfully and the tin has been properly closed for that time.

I think perhaps I should have used primer...

Third_Eye · 10 Nov 2006

Most Copper turns blue green when painted when emulsion is applied over it. It can sometimes happen with some Oil Based Paints also.

Zampa · 11 Nov 2006

Was the satin paint water based by any chance?

Moz · 12 Nov 2006

Verdigris is that a ready meal from M/S

I bet its flux residue ..

robopenshaw · 14 Nov 2006

I bet it's just the copper oxidising! This is a blue/green colour... I'm thinking a base coat/primer coat would have prevented it!

Purely a guess on my part though!

Rob

JamesA · 14 Nov 2006

Moz said:
Verdigris is that a ready meal from M/S

I bet its flux residue ..

I sounds a bit like "third degree" which it what I got off the wife when she'd noticed the pipe had turned blue.

I bought a spray can of white metal primer which seems to have done the job.

tonygerm · 14 Nov 2006

as said before waterbased paint no good 4 copper,degrease with white spirits.prime(calciumb plumbate)undercoat and gloss .....job done

confidentincompetent · 14 Nov 2006

With bare copper I just wipe over with white spirit..(wet rag where the plumber left his flux..) Then a coat of white gloss (thinned a little) No need to prime according to dulux...

That hammerite special metals primer is a load of crap ..

diynot

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Verdigris or dirty pipe turned white paint blue?

breezer

Moz

confidentincompetent

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