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Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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How to choose the best flux for your line?
June 21, 2011
Hi Dr Cook. Thank you for all your input into the industry over the years!
How do you (or any reader) choose which type of flux is best and how do you choose which one to use?
With regards to concentrations used in the flux (g/l), does that differ on the thickness of the material, or how is this established?
There has been quite a bit of talk in SA about nickel additive fluxes, there are relatively small amounts of nickel chloride in the flux and the supplier from India claims that it lowers coating weights or pick up, what are you thoughts on this?
Chemical supplier - Germiston, South Africa
June 28, 2011
Sir:
I like the North American way of galvanizing and therefore would use quadraflux at about 11 to 13 degrees baumé and a pH between 4 and 4.5 and also at about 71 C.
Thickness of the steel is not a factor in flux choice. If iron +2 builds in the flux then a higher baumé may be required.
As far as nickel chloride in the flux, I consider this too dangerous and would not knowingly enter a plant with nickel chloride in the flux. This is a cancer causing material and the target organs are the lungs, throat, etc. (organs of the breathing systems). I also would think that the nickel would be depleted quite quickly and therefor would have to be tested frequently.
From experiments that I have done I expect zinc usage would decrease using nickel chloride in the flux, but the health aspects of the workers, especially if the kettle was not enclosed would preclude its use.
There are far better ways to reduce zinc usage and they are quite safe and quite effective.
Regards,
Galvanizing Consultant - Hot Springs, South Dakota, USA
Hi Dr Cook
Thanks for your insight.
Why are there so many different types of fluxes i.e., double salt, triple salt quad etc.? Do some fluxes work better on certain applications compared to others?
On your recommendation with the Quadraflux, would that be suitable for any galvaniser and any type of work that they are processing, kind of a one fits all?
With regards to your nickel comments, is this primarily because the nickel on the work going into the kettle and the associated smoke would cause a problem? If you look at electroplaters that plate nickel, they use very high contents of nickel in their nickel plating baths by comparison, are the associated health hazards the same?
Best regards
- Germiston South Africa
July 25, 2011
July 25, 2011
Sir:
For the large galvanizer in Germiston, in about 1985, I installed a flux solution with an ACN of about 1.4, previously the ACN was about 0.4. The total savings was about US$8,000,000/year. This was when zinc was cheap. There are a number of variables that also must be controlled in the flux solution to maintain a good result.
For continuous pipes I installed other types of flux, even for different pipe diameters, and again there are a number of other variables that must be controlled to attain required results.
Regards,
Galvanizing Consultant - Hot Springs, South Dakota, USA
July 26, 2011
Sir:
Yes some of the nickel in the flux solution would go into the smoke and then be breathed into the lungs. In electroplating the nickel would primarily be retained in the water solution.
A number of years ago I was concerned about nickel in galvanizing (nickel metal added to the zinc). I contacted the nickel development association and the guy sent me an article which was supposed to show me how safe nickel is. Well this article was a story about an English town where nickel metal was isolated from its ore. After a few years people in the town started dying from cancer. First the nickel workers died then their wives who washed their clothes then the children. The town was called the "town of the walking dead."
Also in the previous edition of the CDC (Center for Disease Control, USA) Handbook of Dangerous Materials, nickel was listed as causing cancer in man and dog, with a 5 to 50 year delay in symptoms from exposure date.
Needless to say my concern about nickel exposure persists.
Regards,
Galvanizing Consultant - Hot Springs, South Dakota, USA
Hi Dr Cook
Thanks for your insight however the suppliers of the nickel additive flux are persisting that these concerns raised are unfounded. They claim that the nickel gets alloyed into the zinc coating and does not burn off and cause carcinogenic smoke, they state that it is only the ammonium chloride in the flux that burns off and causes smoke?
What then happens to the zinc chloride and this nickel?
We are trying to educate the users on the possible dangers but the seller is just interested in making the sale which I find as being irresponsible.
Is there any other data that I could download to support these concerns?
Best regards
- Germiston South Africa
September 5, 2011
September 8, 2011
Mr. Jones:
I recommend that you have the ash (skimmings) of a user (galvanizer) of this nickel chloride flux tested for nickel.
Are you a sales rep. for this nickel chloride flux company or do you work for the galvanizer in Germiston?
Any nickel at all in the ash (skimmings) would be a source of concern. The developer of this nickel chloride flux should demonstrate that it is safe.
Regards,
Galvanizing Consultant - Hot Springs, South Dakota, USA
Not sure there's any doubt about what Ni can do, healthwise.
But is there evidence that Ni from Ni-bearing flux is in the fume and that the toxic quantities are ingested, breathed or taken some other way?
The presence of a dangerous substance isn't grounds enough to stop its use. There has to be evidence of a link showing how it would move into the body to have its toxic effect.
If we just refused to go where there are dangerous things, the world would not be a place to stay!
Geoff Crowley
Crithwood Ltd.
Westfield, Scotland, UK
September 8, 2011
October 5, 2011
Dr Cook
I am not a "rep" for this nickel based flux, we supply a product called Galvastop/Stopgalv and a few other products.
Initially my questions to you were just regarding the pick up reduction that is being claimed by using this nickel based flux. With the amount of nickel in their flux it is difficult to believe because it would be consumed pretty quick, but it was you that pointed out the associated health risks with using nickel in the flux which I was not aware of.
As I mentioned these possible dangers were not pointed out to the galvanisers who use this type of product and in fact I have forwarded your comments to a lot of them to make them aware of this, however as a sales person would, the supplier is saying that this is not the case and that the nickel would get alloyed in the zinc layer and the smoke is only caused from the ammonium chloride.
Your comments would be appreciated
Best regards
Donavan
As Geoff rightly said, I would like to pass on some concrete facts about this to the users.
- South Africa
October 7, 2011
Donavan,
Nickel causes cancer, usually lung, throat, voice box, etc. all related to breathing functions. Lead is toxic and causes reproduction problems. Both are listed in the CDC handbook and on California Proposition 65.
I have recommended that you have the ash/skims of a galvanizer using nickel flux to determine if nickel is present. If it is in the ash/skims then it is certainly in the air. I advise you again to do the testing.
As a young lad I was poisoned while making lead fishing sinkers. A few years ago I had a horrible rash from the outside corners of my eyes to my ears from nickel in eyeglass frames. It took many months of treatment for this rash to clear-up.
For your information I have galvanizers using my new process which is lead-free, nickel-free, bismuth-free, and tin free. Thus you see I am not a neutral judge of nickel use in hot dip galvanizing. I have however read several articles relating to the cancer activity of nickel and I truly am concerned about nickel and also lead.
Regards,
Galvanizing Consultant - Hot Springs, South Dakota, USA
October 11, 2011
Thanks Dr. Cook
I echo your concerns and that is why I have been asking these questions to alert the users of these dangers!
Regards
Donavan
- South Africa
October 12, 2011
Sir:
I am at the AGA Tech meeting in Columbus, OH and a flux company guy from Hagen, Germany is here and he says that nickel chloride added to the flux solution does not work.
He says that control of the flux is very difficult and high concentrations of nickel chloride are required and when the flux solution would be contaminated there is no place to dispose of it.
Galvanizing Consultant - Hot Springs, South Dakota, USA
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