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topic 32993

Formulation of pickling paste for stainless steel


A discussion started in 1999 and continuing through 2020 so far.
Adding your Q. / A. or Comment will restore it to the Current Topics page

1999

Q. How would you spot passivate a weld in 316L SS using nitric acid in a suspension, specifically what concentration of nitric acid would be used, what would be the gel substance, and what time period would you recommend.

Any assistance would be appreciated.

Best Regards,

Chris [last name deleted for privacy by Editor]


1999

A. There are commercial products for local passivation of stainless steels after welding. Try asking at a local welding shop. I know that Avesta, a stainless steel company, is one supplier of a passivation paste product.

larry hanke
Larry Hanke
Minneapolis, Minnesota


1999

A. You can perhaps gel the nitric acid with Fumed Silica [affil. link to product info on Amazon].

My prejudice is I dislike gelled acid for safety reasons. Further, since acids function by reacting with metal, and the gel impedes fresh solution flow to the surface, I think they are less effective than liquid acids. But I would think that you can just follow the regular passivation spec (QQ-P-35C [link is to free spec at Defense Logistics Agency, dla.mil]) for nitric or nitric-chromic passivation.

Is it impractical to just repassivate the whole welded structure?

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha


1999

A. Chris, You could use Brush Electroplating to selectively passivate the areas that need to be done. Depending on the size of the areas it could go fairly quick.

David Crocker
- Valencia, California



Thickeners for Pickling Paste

2000

Q. I'm interested in knowing what kind of thickeners I can use with strong acids, like nitric acid, to prepare pickling paste or a paste with phosphoric acid to phosphatize metal surfaces. I'm working with resins for coatings and paints in general, and this kind of knowledge helps me in preparing surfaces before painting. As I'm in Brazil, commercial names are difficult to find, so, I'd like to know the chemical names or the name of raw materials suppliers All suggestions are welcome. Thanks in advance.

Sergio Henrique Klein
- Novo Hamburgo - RS - Brazil


February 1, 2012

A. Dear all,

For thickening weak or strong acids you can use Ethomeen C12 from Akzo or Cecajels from Ceca. Cecajel 210 for many Weak and Strong acids (HF, Phosphoric, Citric); Cecajel 300 for Sulfamic acid; Cecajel 250 for Hydrochloric acid.

Hope this helps.

Ron Vos
- Hoofddorp, Netherlands


February 1, 2013

A. Thanks Ron for doing what you could. Sergio asked for the chemical names of raw materials and I think fumed silica and barium sulphate are the most common generic thickeners, although maybe not the equal of commercial products :-)

I suspect, but don't know, that fumed silica would be unsatisfactory for mixes that contain hydrofluoric acid. Regards,

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha



To minimize search efforts and to offer multiple viewpoints, we combined previously separate threads onto this page. Please forgive any resultant repetition, failures of chronological order, or what may look like readers disrespecting previous responses -- those other responses may not have been on the page at the time :-)



2003 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I would be interested to know what gelling or thickening agents or binders can be used for acid pickling which are stable to nitric acid (50% conc.). Most of the gels I tried are not resistant to higher concentrations of nitric acid.

Shashibhushan Vaidya
pretreatment and cleaning chemicals - Mumbai, Maharashtra, India



2004

Q. To prepare the paste with HF & HNO3 what filler to be added?

Rajendran Sun
metal treatment chemicals - Chennai, Tamilnadu, India


2004

A. Hi Rajendran. The more common thickening agents will not work because the HF will attack Fumed Silica [affil. link to product info on Amazon] and the HNO3 will attack cellulose thickening agents. Sorry, I don't know the answer. One thing you could do is review expired patents on the subject, or you could buy some and reverse engineer them.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha


2004

A. The thickener is barium sulfate.

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg, South Carolina


2005

thumbs up signDear Mr.Sun,

It will be some really mad person who will disclose its proprietary chemistry to you and the world. You may better go to some Chennai five star hotel and ask the recipe of their speciality cuisine and get same feedback from them.

Jenny Smith
- Texas


March 18, 2009

affil. link
Calcium Gluconate
for HF acid burns

Hi, Jenny. You're right, of course, that proprietary knowledge won't be shared. Still, there is a constant & continuing shift between what constitutes proprietary chemistry versus what is generic info that is discussed in technical conferences, journal articles, and industry websites. The worldwide patent system, with patents having a limited life of 20 years, was established with the specific goal of encouraging progress through ideas becoming public knowledge after a time.

Some people may consider the thickening agent for gelled acids to be proprietary information but, as you see, some other people consider at least some thickeners to be just generic info.

Users must make sure they have the calcium gluconate first-aid antidote on hand at all times, and a clear plan for proper follow-up medical treatment before even getting near hydrofluoric acid.

Regards,

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com - Pine Beach, New Jersey
Striving to live Aloha



Stainless Steel Pickling Alternatives

2007

Q. Dear sir, I don't have a pickling solution and pickling paste how do I make this solution? urgent ... thanks everyone ... if any can give me some info. Please, I will very appreciate. thanks

Jason Leong
chemical finishing - Kuala Lumpur, Selangor, Malaysia


2007

A. Buy a copy of ASTM ASTM A380 [link is to the practice at TechStreet] , 'Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems.' It gives many solutions as well as useful application information. Note that improper usage can cause intergranular corrosion or hydrogen embrittlement in some cases.

Pickling paste is usually pickling solution thickened with an inert ceramic powder, but perhaps most users buy from welding suppliers.

Ken Vlach
- Goleta, California

contributor of the year

Finishing.com honored Ken for his countless carefully
researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work
which the finishing world continues to benefit from.




Pickling paste without hydrofluoric acid

June 10, 2009

Q. Is there a pickling paste available for post weld finishing of stainless steel available with no hydrofluoric acid. I'm aware of <0.5% pastes but not Zero hydrofluoric.

We produce a mobile electropolisher, so are interested in developments in pickling paste

Richard Ray
manufacturer of post weld finishing machine - Ballina, NSW, Australia
outdated


June 30, 2009

A. This is a very difficult task.

adv.
We have successfully developed green" pickling pastes without nitric acid for stainless steel, carbon steel, titanium. We are currently working on eliminating hydrofluoric acid also. However work is not completed yet.

anna_berkovich
Anna Berkovich
Russamer Lab
supporting advertiser 
Pittsburgh, Pennsylvania 
russamer labs banner



April 22, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I am a person involved in pickling & passivation of Stainless Steel. Right now I am doing a conventional method. The process is by the use of hydrofluoric & nitric in a proportion.(Liquid form)
I want to make use of the same proportion in paste/gel form.
So kindly let me know that which ingredient to be used for the above to bind it in paste/gel form without loosing the properties of the product.
I am looking for the binder to make it happen.

Shafiullah
- - Bogra, Bangladesh



April 14, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Hi I am interested to manufacture stainless steel pickling paste/gel. The product is made by using both nitric and hydrofluoric acid with a gelling agent. Kindly assist me. Thanking you and await your reply.

Anil patel
- Nairobi Kenya


May 13, 2013

Q. Kindly let me know how do I manufacture pickling paste for stainless steel without the use of hydrofluoric acid and nitric acid.

Anal Kulkarni
chemicals - Mumbai, Maharashtra, India


May 14, 2013

A. Anal,

Gels production for pickling, passivation for stainless steel, carbon steel, titanium - are proprietary.

adv: If you want to buy the recipes - no problem - contact me. But free advice - sorry, we cannot.

anna_berkovich
Anna Berkovich
Russamer Lab
supporting advertiser 
Pittsburgh, Pennsylvania 
russamer labs banner



October 19, 2014

Q. I am trying to make a pickling paste and have tried barium Sulphate as suggested.
Formula contained HF 5% and Nitric 30%, but Barium sulphate didn't thicken it. Just wondering what I have done wrong? Please help.
Regards,

Andrew Gilbert
- Queensland Australia


October 19, 2014

A. Not enough barium sulfate. Keep adding until it is the consistency you want.

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg, South Carolina



November 11, 2018 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. How to convert nitric acid and hydrofluoric acid in gel or paste form

akshata ghadi
- mumbai maharshtra india


November 2018

affil. link
Calcium Gluconate
for HF acid burns

A. Hi akshata. As you see, we added your posting to a thread where the question was already answered. But please be aware that when you jellify this very dangerous acid, allowing it to be placed onto surfaces and just sit there where people can potentially be unknowingly exposed to it, you significantly increase its dangers. Please make sure you that are a highly responsible steward for the risks you will be creating. Thanks for your understanding.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com - Pine Beach, New Jersey
Aloha -- an idea worth spreading


August 18, 2020

FOUND ON INTERNET:

Mr. Vinay Golwala was Granted Patent For "Different Stainless Steel Chemical Treatment Pickling Compounds & Processes For The Preparation Thereof" Published By Indian Patent Office.
Indian Patent Claims
1.A process for preparation of stainless steel acid pickling composition comprising of adding 2-15% calcium nitrate and 3-16% aluminium nitrate; dissolving a acidifier 15 -55% of nitric acid and 0.5 -25% hydrofluoric acid; mixing 0.1 -5% polyvinyl pyrrolidone; optionally adding xanthan gum.
2.A stainless steel acid pickling viscous brush gel composition formed by process as claimed in claim 1 consisting essentially of acid pickling agent such as nitric acid and hydrofluoric acid; inorganic mixture of calcium and aluminium nitrate; gelling agent such as polyvinyl pyrrolidone; optional thickening agent such as xanthan gum.
3.A stainless steel acid pickling sprayable gel composition formed by process as claimed in claim 1 consisting essentially of acid pickling agent such as nitric acid and hydrofluoric acid; inorganic mixture of calcium and aluminium nitrate; gelling agent such as polyvinyl pyrrolidone; thickening agent such as xanthan gum 0.05-3%
4.A acid pickling viscous gel composition formed by process described in claim 1, as claimed in claim 2 where the said acid pickling viscous gel composition is formed within 15-30 min by the addition of calcium nitrate, aluminium nitrate, polyvinyl pyrrolidone solution, nitric acid and hydrofluoric acid.
5.A acid pickling sprayable gel composition formed by process described in claim 1 as claimed in claim 3 where the said sprayable gel is formed by addition of xanthan gum to the said viscous gel composition for 2 hr.
Patent Practice and Intellectual Property Services

Anant Karnani
- HYDERABAD, TELANGANA, INDIA



PICKLING PASTE HOW TO GEL FORM ?

October 9, 2020 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Hello ,
I need your help with a product.
As you know, we use pickling gels for stainless steel.
It consists of hydrofluoric + nitric acid.
So how can I get these products in Gel form?

GOKAY ERGUL
- IST TURKEY


October 2020

A. Hi Gokay. We appended your inquiry to a thread which should answer your questions, but feel free to continue the discussion. Good luck.

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Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com - Pine Beach, New Jersey
Aloha -- an idea worth spreading


October 12, 2020

Hi Gokay,

Preparing pickling paste does not involve mixing with organics. The proprietary know-how has been sold to Bama technologies, Italy many years ago. Thanks to in-house mixing, Bama won numerous contracts for maintenance cleaning of large vessels for bio and food industries.

The gels compositions can be altered for summer temperature, for carbon steel, stainless steel, titanium. It is possible to mix 'green" gels, gels for passivation only.

adv.
Contact us if you are serious in obtaining gel technology.

anna_berkovich
Anna Berkovich
Russamer Lab
supporting advertiser 
Pittsburgh, Pennsylvania 
russamer labs banner

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