Passive flux

[davenport.neil]

Can anyone tell me, is residue from passive flux such as "la-co" corrosive after the soldering process is complete?

Thanks.

 

[Deleted member 25704]

Yes la-co is corrosive, just as all fluxes are. However, it is gas council approved and is suitable for use in the uk for water as well.

It should be used with caution - only flux the male ends, not the fittings, and removed with a damp cloth after soldering. Heating systems should be thoroughly flushed, both hot and cold to get rid of any internal residues.

However, if these conditions were not satisfied, flux on the outside of joints leaves a green unsighlty residue.

On the inside of systems, it an be argued scientifically through sampling and scientific reason, that an increase in the ph of the system water acts as an electrolyte and may lead to electro-chemical corrosion in the prescence of disimilar metals usually found in heating systems. However such occurances would not be down to the flux, but down to occupational quality.

 

[davenport.neil]

Yes la-co is corrosive, just as all fluxes are. However, it is gas council approved and is suitable for use in the uk for water as well.

It should be used with caution - only flux the male ends, not the fittings, and removed with a damp cloth after soldering. Heating systems should be thoroughly flushed, both hot and cold to get rid of any internal residues.

However, if these conditions were not satisfied, flux on the outside of joints leaves a green unsighlty residue.

On the inside of systems, it an be argued scientifically through sampling and scientific reason, that an increase in the ph of the system water acts as an electrolyte and may lead to electro-chemical corrosion in the prescence of disimilar metals usually found in heating systems. However such occurances would not be down to the flux, but down to occupational quality.

Thank you for your response.

So would i be right in thinking that in the case of gas, as some flux residue will find its way inside the pipe due to the fact that the solder is drawn in by capillary action, that it is not a case of if the pipe will corrode from the inside out but just how long it might take?

 

[Deleted member 25704]

I think you could reason this argument that corrosion would go on etc. However, the science which made the product approved, has to be trusted until such times new scientific data is available. I do not know if there is any published data on this issue, but it is an argument which has often been raised in plumbing circles - some plumbers will not use la-co for this reason. However, I do, because there is no scientific argument other than anecdotes to convince me otherwise.

 

[SimonG]

Green pipes, my pet hate. Doen't take a couple of seconds to wipe it down.

I'm not sciency and won't pretend to be, but is corrosion not oxidisation, and as gas doesn't contain oxygen then you shouldn't get oxidisation?

Steps back and waits for the clever lot to put me right!

 

[AWheating]

on wet pipes it gets flushed so dont worry, on gas clean and use very little flux on pipe only. Theres no 100% garantee you will not leave a small amount inside a pipe.

More importantly than what flux is how long. How long the pipe is going to be left de commissioned. If your turning the water on straight away after the work is complete to enable you to flush the pipework then you should have no problems. If your not going to commission for a while, like you would on new builds/ 1st fixes then you must fully flush the pipework straight away bwfore leaving empty. Not flushing can leave contaminates to corrod and bacterial can grow which its dangerous for health reasons. Made even worse by plumbers on new builds using dirty from storage tubs and dirty containers when pressure testing.

obviously on heating systems chemicals can be used to clean and avoid corrosion.

 

[wheeto]

... gas doesn't contain oxygen [so] you shouldn't get oxidisation?

That's exactly what I've always thought but I've never heard anyone else say it before, let alone say it with authority!

 

[lame plumber]

That's exactly what I've always thought but I've never heard anyone else say it before, let alone say it with authority!

contains some water residue tho and thats made of?

 

[Guest123]

My pet hate is seeing snot soldered pipes covered in green flux residues. Shows a lack of skill and care for their work.

As for flux, let the fitting cool naturally (never cool a fitting straight after soldering as capillary action is still taking place) and after about 2 minutes, wipe it over with a baby wipe and the flux is removed and the pipe stays clean.

 

[wheeto]

contains some water residue tho and thats made of?

Oxidation requires free oxygen, and water doesn't spontaneously decompose much. If it did we'd be living in a hydrogen economy (and quite thirsty).

 

[Billy Bob Bob]

Can anyone tell me, is residue from passive flux such as "la-co" corrosive after the soldering process is complete?

Thanks.

yes its worst than passive smoking your arms/legs/fingers/lungs/head/todger/nose etc might rot away and fall off

 

[neily01]

They tell me that laco is only active when heat is being applied that was why it use to be the preferred choice

 

[kozak1968]

If You that worried ( I'm not) use Yorkshire flux

 

[kay-jay]

yes its worst than passive smoking your arms/legs/fingers/lungs/head/todger/nose etc might rot away and fall off

Hmm is it worse than say powerflux? I thought la-co was non-toxic and therefore not as bad for you in terms of fumes and irritation etc.

 

[badabing04]

La-co turns your hands green as well!

 

[AWheating]

Hmm is it worse than say powerflux? I thought la-co was non-toxic and therefore not as bad for you in terms of fumes and irritation etc.

powerflux is not recommended for gas pipework, laco is. what the difference is i cant say for sure. powerflux is acid based from memory.

 

[kay-jay]

yes it is acid based, and i dont like the smell of it either.

from the fernox website

Powerflow Flux has been successfully used in gas systems for many years. However there are people who
prefer not to use a self-cleaning flux in a gas pipe system. If this is a concern, then Fry Fluxite Paste flux is
recommended.

 

[kay-jay]

from la-co hazard sheet
Potential Health Effects ACUTE (short term): see Section 8 for exposure controls
Relevant Route(s) of Exposure: Skin contact, Inhalation.
Inhalation: Inhalation of vapors is not expected with normal use. Over exposure to high vapor
concentrations may cause nasal and respiratory irritation, sore throat, coughing and difficulty
breathing. High concentrations may also cause dizziness, headache, nausea, vomiting or in
extreme cases, unconsciousness or asphyxiation.
Ingestion: Not an expected route of occupational exposure. Low oral toxicity. Swallowing large
quantities may cause abdominal and chest pain, nausea, vomiting, diarrhea or dizziness.
Aspiration into the lungs may occur during swallowing or from vomiting, resulting in lung injury.
Skin: This product has been tested and found to be non-irritating to skin.
Eye: This product has been tested and found to be non-irritating to eyes. Solids may cause
temporary irritation as a foreign object in the eye.

 

[kay-jay]

from the powerflux hazard sheet

Section 07 Health Hazard Data
Eye: Irritant. May cause corneal injury.
Skin Contact: Irritant.
Skin Absorption: No evidence of adverse effects.
Ingestion: May irritate or burn digestive tract.
Inhalation: Fumes will irritate nasal lining.
Systemic & Other Effects: N/A

 

[kay-jay]

think i will stick with the non-toxic, non irritant,non blinding and non acid la-co:44:

 

[AWheating]

im mixing the two together this week as a test, if it works ill post my opinion.

 

[kay-jay]

It works.
Probably not a good idea though as mixing two stable chemical compounds can create a potentially dangerous hybrid.

I abhor powerflux and normally use la-co.
Im doing bathrooms refurbing work on council estate at moment and get provided with powerflux. The acid in it is annoying as it stops fittings going on full slip sometimes and also makes it harder to spin or remove fittings from pipe. So when assembling those hard to reach joints under the bath i use my own la-co but my brush is already covered in powerflux....this is how i know mixing works...:banghead:

 

[AWheating]

i prefere powerflow as it works better but it binds fittings like a titch, so ive been using laco recently. Its ok but does not run and give you the confidence you get with how powerflow works.

I used to mix fluxes years back with good results, but have never tried powerflow and laco. I used to mix powerflow with a non self cleaning flux 50/50 and it worked really well and never caused fittings to bind. My old compay stopped buying the standard flux so i converted to just powerflow but not through choice.

 

[mutley racers]

Bind? Is that flux lock?

 

[AWheating]

Bind? Is that flux lock?

yes?

unless your using your flux for some sort of sexual/medical use??

 

[Mike Jackson]

We were supposed to use powerflow on the warmfront jobs but I never get on with it so I used to get powerflow on the company account and swap it for everflux with a guy who liked it. I them filled an empty powerflow pot with the everflux so if H&S came round it looked like I was using the flux they specified.

 

[hammers4spanner]

who cares !!

 

[Whyme]

Eye: This product has been tested and found to be non-irritating to eyes. Solids may cause
temporary irritation as a foreign object in the eye. trust me it does hurt your eyes. I got a splat of laco in one once and vision went blurry for about 2 hours. i was under the pipe soldering mind.

 

[sky]

eats through copper if not washed off