compression connection on painted pipe

[kent]

I am (still!) installing a power shower and have reached the point where I have to connect to the pipe emerging from the top of the hot water storage tank. This pipe is painted with old paint which shows no signs of flaking. When I fit the compression T connection to this pipe should I first remove the paint or will it contribute to the compression seal? If it is better to remove the paint, what is the best way of doing this? Thanks to anyone who cares to reply.

[Burbeck]

Hi Ken, the main thing is don't scratch the pipe by scraping with tools etc as the compression fitting will weep/leak.

it is important to remove every trace of paint an inch or so from the end of the pipe, i use heat from a blowlamp to soften the paint then wire wool while its still hot, be careful not to burn fingers.

strong paint remover and wire wool is ok but slower use gloves

don't forget the back side of the pipe awkward to see if the paint is completely removed use small mirror and torch to look. regards bob

[weekendwarrior]

Remove the paint with some wire wool.

You may find that you will struggle getting the compression nut an olive over the pipe if you don't

-- weekendwarrior

[The Natural Philosopher]

wire wool it off completely.

Old pipe is bad news anyway ..if possible replace it.

[ClingF]

Scrape along the pipe with a fairly blunt object to remove the paint, if it has been there any length of time it should be readily removable due to the fact it has become brittle. Remove residue with wire wool.

I would avoid heat, unless absolutely necessary as this can "bake on" paint, leaving the carbonised deposits difficult to remove.

It is possible to avoid damaging the exterior of the pipe by using blunt tools. It is also possible to remove olives from the pipes by judicious use of a hacksaw without damaging the pipe. I've done it many times.

A compression joint pipe sealant should be used in any case when remaking the joint. Many compression joints would leak without the application of such assistance.

[The Medway Handyman]

Bobs advice is spot on, it has to be perfectly clean & free from old paint or it will leak. These are well worth the money

[John Stumbles]

You'll probably have to get the paint off to get the new nut and olive on but if you can get away without doing so that's OK. If the new olive is loose on the pipe then you may have old 3/4" Imperial-sized pipe, in which case you ought to use 3/4" rather than 22mm olives (but with a

22mm fitting). Getting paint off is a PITA. Sometimes twisting a pair of water-pump pliers round the pipe will crack up the paint if it's brittle, and something with a not-too-sharp edge (e.g. side of a chisel) can help off the rest. Blowlamp and scourer (like wire wool but coarser, used for cleaning saucepans) is good. It doesn't have to be perfect: just use suitable sealing stuff like Boss Green or True Blue.

[Ed Sirett]

Abrasive straps sold by Rothenburger and others (available at real PMs') are THE tool for this.

[kent]

Thank you all for some excellent tips and advice. I'll probably try the chemical paint remover approach as it wouldn't be easy to use a blow torch safely in this location. I'll hope it is not an imperial pipe! The house was built in 1973 but the previous owners re-located the storage cylinder, although this particlular pipe looks old. Many thanks.

[Roger]

The message from kent contains these words:

I missed the earlier thread as I have been away but one job I had at my sisters was to connect onto painted pipes when replacing a low level cistern.

The supply was either 15 mm or half inch and the overflow 3/4" copper, both painted. I scraped the paint off the pipes at the new junctions and used compression fittings to connect as I didn't want to use a blow torch so close to the tiles for the overflow and I was putting in an isolator in the feed.

Half inch and 15 mm are so close in size that it doesn't matter. 3/4" is marginally smaller than 22 mm so a 3/4" olive (widely available) has to be used in 22 mm compression fittings. 3/4" to 22 mm solder fittings are also available if needed. (I am not sure but I think only end feed fittings, not Yorkshire solder ring).

[Dave Plowman (News)]

I doubt you'll be able to get the olive on over paint. But anyway it should be removed. Paint stripper followed by wire wool. Don't scrape it off as deep scratches will cause a compression fitting to fail.

But unless you need to dismantle in the future use solder fittings. Practice first on scrap - but they are cheaper, neater and more reliable.

[kent]

I finally tackled the pipe today and am pleased to say that the paint stripper worked a treat. I gently agitated the stripper with wire wool on the stubborn areas and in no time the copper was as bright as new. Thanks to those who gave advice.