Letter 41059

Alternate for Phosphating  

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Sir,
We are dealing with INJECTION MOULDING MACHINE manufacturing & we have our own paintshops in which we carry out painting -mainly Poly Urethane based.We would like to know about the alternate methods of degreasing process/phosphoric coating prior before primering on our product.

Rejith.G.R
Quality Assurance engineer - Chennai, Tamilnadu, INDIA

Has an eight hundred-pound gorilla entered the room with no one acknowledging it? This is at least the fourth request from India this month asking how parts can be painted without a phosphate pretreatment--but no one is saying why everyone suddenly wants to do that. Is there a new restriction on phosphates in wastewater? Is someone making the rounds claiming that phosphating isn't necessary? Please tell us why you would want to get away from the pretreatment that has proven itself around the world as the most cost-effective and robust treatment in thousands of applications, Rejith. Thanks.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Dear sir,
Thanks a lot for your reply. As you asked I wish to say some problems we encounter with phosphating is ...
1)It takes away the shining on the components which doesn't require paint coating over that.i.e, the fresh (originality)look of certain parts (like SS sheets,chrome plated elements) in our machine is lost.
2)And once after stipulated time expires, phosphating lead to rust formation & in certain cases it penetrates and causes for pre-mature pitting on that.
3)And the continous exposure with this chemical will lead to some health related problems like suffocation & moreover this is not environmental/user friendly as you know.
Please suggest...anticipating your fav.replies.
Regards,
Rejith.G.R.

Rejith.G.R
- Chennai, Tamilnadu, India

Their is lots of alternative treatments, many of which are used by my employer. Most are OK but none are as good as Zinc Phosphate. If you use no treatment count on having adhesion problems.

Ronald Zeeman
Coil Coating - Brampton, ON, Canada

Dear Mr. Rejith,

Many common metals are unsuitable for a variety of applications in the form in which they are initially produced, being quite susceptible to corrosoion as they come from the mill; they should have their surfaces altered in order to make them more useful. The performance of all painted and ;powder coated finishes depends on the correct preparation of the metal substrate. Failure of coatings in service with problems such as corrosion and blistering are nearlhy always causesd by inadequate pretreatment.

Such pretreatment depends upon :-

1. What is it that we want to protect?
2. From what do we want to protect it?
3. What is the quality standard we look for ?
4. What is the productivity we need?

You want 'an alternative method of degreasing process/phosphate coating prior to painting. Our product FERROGUARD is a composite chemical, which
> removes thin wet films of oil and grease;
> removes light to medium rust; and
> finally forms a composite phosphate coating firmly adherent to and integral with the surface being treated.

The treated surface is now ready for painting.

FERROGUARD is applied by brush and finaly wiped dry, not rinsed dry. The residual chemical after wiping will spend itself out by reacting with the base metal.

FERROGUARD may be used to treat components made out of steel and galvanized surface.

FERROGUARD is not a panacea for all metal pretreatment problems. If you write to us tell us what is the standard you look for, we will write to in detail.

EVERY ASPECT OF METAL FINISHING THAT IS WORTHY OF CONCERN AFTER THE PARTS HAVE BEEN FINISHED IS WORTHY OF CONSIDERATION BEFORE THE PARTS ARE FINISHED.

S. MEENAKSHISUNDARAM Guardian Anti-Corrosives Private Ltd. CHENNAI, TAMIL NADU, INDIA

Rejith,
1). If you are painting and plating,you might consider doing the painting first. The painting will act as a mask, and the chrome plating will be shiny because it will follow phosphating rather than preceding it.
2). Phosphating is a pre-paint treatment, not usually meant to be a final finish; I don't really understand the corrosion problems you are mentioning.
3). Please describe this 'suffocating'. I am not aware of any health related problems for phosphating when the usual common sense safety measures are in effect. Similarly, I know of no environmental problems associated with phosphating except perhaps the release of phosphate-rich rinse water; and even in that case, dry-in-place phosphate coating systems exist. Good luck.

Ted Mooney finishing.com Brick, New Jersey

Nanoceramic - Bonderite

One of the best surface technologies that can replace phosphating.

Best Regards,

Boris Smoje
specialist - Serbia, Belgarde

Dear Sir,
There are water borne polymers ranging from epoxies to polyurethanes with which you could eliminate phosphating process.However,you need to remove grease and rust(in case the component is rusted), rinse twice in DM water,dip in water borne polymer bath(from 3% to 5% concentration.Allow an intervel of 20 minutes.Then,proceed for further top coat by powder coating or liquid top coat.If not you can leave the component atleast for a week.
HOPE THIS WOULD RESOLVE YOU ISSUE.
Thanks,

Balaji Viswanath.b
- Bangalore, Karnataka, India

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