Ask Cougartron Part 1: Difference between electrolytic weld cleaning fluids and the pickling paste

Weld cleaning | Ask Cougartron | Wednesday, 20 December 2017

Ask Cougartron Part 1: Electrolytic weld cleaning fluids vs. pickling paste

We are extremely happy with the response we got after launching our Ask Cougartron program last month.

In the first video, Harry – our sales area manager – talks about electrochemical process safety and explains the difference between electrolytic cleaning fluids and pickling paste.

Your Question: “Both methods use acids, why do you say that the electrochemical method is safer than pickling?”

Safety of the weld cleaning process is a common concern so this is a great opportunity to explore the topic in detail.

Let’s get straight to the point.

Why is pickling paste harmful?

The pickling paste contains hydrofluoric and nitric acids – both highly harmful to the human body.

Hydrofluoric acid is a dangerous threat to various parts of the human body and can be absorbed through inhalation, ingestion, and contact with skin and eyes. Symptoms range from simple irritation to serious medical conditions such as skin and bone disease.

Acid often penetrates the skin and reacts with the calcium in the blood without obvious symptoms at the very beginning. This means that side effects can often only occur after tissue decay has become significantly advanced.

Washing the affected area with water is of very little help since the acid penetrates the skin quickly and can only be sanctioned by a medical procedure.

Nitric acid is less harmful to the internal organs. However, it causes significant chemical burns and leads to tissue decomposition.

Any contact between the body and the pickling paste results in significant medical problems – That is why all operators have to use extensive protective equipment and go through detailed training. Additionally, factories operating with the pickling paste are in many areas legally required to obtain special permits.

Read more about the dangers of the pickling paste here

Are electrolytic weld cleaning fluids safer?

The acid component of electrolytic weld cleaning liquids is phosphorus-based.

Cougartron uses the same class of phosphoric acid that can also be found in soda drinks and home-cleaning agents. The only difference is the concentration of the acid which is a bit higher when it comes to weld cleaning liquids.

Since the acid is mild and insufficient to eliminate oxidation itself – the second component of the electrochemical process is a low-voltage current that provides the desired effect. The process results in minimal evaporation and the emerging steam is essentially harmless.

A certain level of hazard is associated with the use of any acid, but mild phosphoric acid used during weld cleaning reduces this risk to a minimum and requires the use of only basic protective equipment. It also represents an insignificant threat to the environment.

Conclusion

Although both processes use acids, electrochemical weld cleaning is much safer than pickling given that phosphorus-based electrolytic fluids are mild and low-risk.

They do not represent any significant threat to the human body, unlike hydrofluoric and nitric acids, which are found in the pickling paste.

Phosphoric acid is mild and therefore our machines use a weak electric current to achieve the necessary reaction with the stainless steel surface and eliminate all imperfections after welding.