Good trick, or a real no-no?

[Sadly]

Another simple question :)

I have noticed that soldered joints often get discoloured (a bit blackened due to oxydization). This happens much more with lead-free solder which seems to require a little more heating than the older stuff.

If the fitting is going to be visible (even if only short term, e.g. untill the room is next decorated) it looks bad.

I have realised that this oxidization can be removed by a powerflux. I have tried a thin smear of powerflux left for about 10 minutes, then cleaned well with a damp cloth - much better looking joints.

Is this a known trick, or a known no-no?

[Nigel Molesworth]

It's acid, so removes the oxidation. I'd be inclined to *wash* it off.

[Peter Taylor]

I was taught to always wipe a new joint with a damp cloth while it's still warm (i.e. after the solder has hardened). As well as cooling the pipe for safety, any left-over flux is removed so it won't go green and the pipe is cleaned up in the process.

I don't think you'll ever keep the solder shiny for very long, lead-free or not. maybe you could try end feed fittings with silver solder. :o)

[Dave Plowman (News)]

Why not just give it a 'polish' with wire wool if you're worried about looks?

[Sadly]

Could do...

The only reason I am that bothered is that SWMBO thinks that some of the new pipework, where it is exposed to view, looks grubby - but she is perfectly happy with bare copper. I normally give a good wipe with a damp cloth after the joint is cool-ish (to get rid of any remaining flux) but this doesn't remove all the oxidization.

I shall continue using a smear of flux to remove bad cases of blackening as it seems to do the trick perfectly. I expect the piepwork will all be painted before the end of 2006.

[Nigel Molesworth]

Why not use primer? Keeps SWMBO happy for years, and takes minutes.

[Geoffrey]

It wouldn't keep me happy but as I'm the one who does all the painting I suppose I don't count.

[Nigel Molesworth]

Better than bare pipes though.

An alternative (assuming you can live with paint on the walls and floor, plus bits of carpet in the paintwork) is to let her paint it.

[Ed Sirett]

This is the recommended method to clean up pipes provided the flux is thoroughly removed. It it not done often as it often isn't needed.

[meow2222]

bare copper looks fantastic if its polished and kept shiny, but its a high maintenance business, as copper oxidises and corrodes readily. I saw one place where the copper pipework was polished up regularly, and it did look quite something. Beats boxing in any day.

NT