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Plant Management

Parts Cleaning articles from Products Finishing are selected and categorized by application for quick reference:

Bromine Solvent   06/01/08
I recently heard from a customer of ours that some electronics firms are forbidding the use of bromine-based solvents in cleaning their components. No specific reason was given. Have you or your cleaning experts heard of such a recent ban? I would appreciate any information you have.

Banned” versus “Regulated”   04/01/08
like the reference to “regulated” when it comes to federal requirements. Everyone seems to think these materials are “banned.”
Also, from a technical standpoint, cyanide is not a metal. To cite one case in our local community, a contractor was starting up a coating operation that used iron phosphating and powder coating. The city did not even require an environmental impact statement.

Cleaning Used Hooks & Racks—Dec. ’01   04/01/08
Mr. Peterson, regarding the above article, the writer indicates that there is a new type of cover or cap that is made from a conductive silicon that can be fitted over the existing hook. After painting, it can be removed and replaced with another one. I would appreciate if you could let me know which company manufactures this product.

Etching during stainless passivation   04/01/08
I have a couple of questions about the etching problem finishers run into when they passivate stainless steel. I see many different causes described in the PFOnline archives, but looking at the causes listed I would have trouble convincing a customer that these things take place without published data or studies. I’ve been in the industry for 30 years now, and have to admit that I don’t have the information at hand to give something to a customer that will convince them we simply haven’t strayed from our process travelers. Do you have a list of recommended sources I can buy for that purpose?

Iron Phosphate Start-Up   12/01/07
I read an article you wrote on PFONLINE. I was hoping you could give me the short answer or a reference for what the wastewater issues may be with iron phosphating. I understand it is safe, but can't find specific information about it and would like an expert's point of view. What do you think about iron phosphatizing and wastewater issues? Any information you can offer would be greatly appreciated.

Rinse Tank Water PH   12/01/07
Some of our customer specifications call for rinsing anodized, chromate-selaed parts in cold (ambient) water, while others call for a hot water rinse. What effect, if any, will raising the temperature of RO water in a post-anodize, post-chromate rinse tank from ambient to 130°F have on the water's pH value? Is there a way to rinse in hot RO water, max 130°F, and still be able to maintain a pH level on the part between 5.5 and 8.0 or the water in the rinse tank?

"Fuzzy" Parts   10/01/07
We are chromating impacted parts made from 7075 T6. We are noticing that some of the parts form a "fuzz" where they are machined. This area is white powder and when removed leaves a black spot on the surface of the tube that will not chromate. The issue is sporadic and can occur at any stage of chromating, but is primarily seen immediately upon removal from the soak cleaner. We have tried four proprietary cleaners and still have some of the same issues. We have also determined there are no stray currents. Could this be the blisters that you have written about?

FOLLOW-UP: Passivation Before Heat Treatment   10/01/07
To Readers: I received a very good email from D.H. discussing the August 2007 question regarding the passivation and apparent rust on 17-4PH precipitation hardenable stainless steel. One significant point that I did not mention was that the passivation process may be better done prior to heat treatment. Either that, or an acid cleaning process may be necessary to remove surface contaminants that could be diffused into the surface depending on the time, temperature and atmosphere of the heat treatment.

Matching Up With Manufacturers   10/01/07
There is a page on PFONLINE where you answer a question about preserving copper plating on Torlon. I am interested in plating Torlon with copper but have been unable to find anyone who has that ability. Could you give me information as to who can plate Torlon with copper?

Residual Smut?   08/01/07
We're having a problem with small cylindrical parts and small amounts of residual "smut" left over after our cleaning at an outside cleaning vendor. In this case the parts are cleaned as follows 1) vapor degrease 2) alkaline clean, 3) citric acid passivation, 4) rinse. The residue is found in the ID of these parts when wiping the ID with a cotton swab. The material is type 304L stainless steel. Do you have any advice on how to eliminate or remove this smut? Parts are sensor housings and must be clean for later electrical processing.

Zinc Removal   08/01/07
I own a powder coating shop and process large amounts of both steel and aluminum. I have a three-stage wash with a multi-metal iron phosphate single-stage cleaner. I now have a customer who wants to bring in galvanized panels from China, and I'm concerned about the zinc going into my waste stream. Where could I find a solubility versus pH chart for zinc?

Clean Steel Using COR Rinse 404   06/01/07
We have been using cor rinse 404. Could you tell me if there are any issues with adhesion with different paints systems? How do you check if the metal is clean?

Cleanliness Test   06/01/07
The application I have is a cleanliness requirement for a metal washer. Please let me know if you know of a test kit available to perform this type of analysis.

Hazy Parts   06/01/07
We have a turntable washer with two stages: cleaner coater and rinse with tap water. The parts to be cleaned and powder coated are CRS sheetmetal boxes, enclosures, etc. The cleaner we used for four years worked great until recently. After the initial few days of the new bath, the parts start to develop a haze when cleaned. When it's been long enough it's so thick you can't see the metal in areas where the sprays don't directly hit. Every time I titrate and add the chemical, it disappears for a short time.

Stainless Steel Wash Primers-Which and Where to Get It?   06/01/07
I have a couple of hundred 3/16-inch 304-stainless steel dowels that I need paint to bond too. I am not concerned about corrosion, only concerned about proper bond of paint to the SS. Besides the obvious degreasing and sanding, I keep reading of "Wash Primers." So what brands are there and where I can I get them?

Clingier Can Be Better   04/01/07
Gel cleaners extend dwell time, provide better cleaning

Blisters And Creep On Aluminum Castings   02/01/07
We have repeatedly failed a 336-hour salt spray test on an aluminum casting. Our pretreat system and coating have met the same requirement on steel and a shorter salt spray test on aluminum castings.

Removing Rust, Mill Scale And Oils In One Step   02/01/07
We have a small job shop that powder coats. We do parts of varying sizes all the way up to 20 ft in length, made of steel or aluminum, occasional magnesium. The parts we receive, as stated before, are constantly different sizes and shape and some of it is made of HRS steel and has rust and corrosion on it, as well as oil. I always see the typical pretreatment stages to be a cleaner, rinse, phosphate, rinse, sealer, rinse or not. Nowhere do I see anything to deal with the rust and mill scale from the HRS steel. Is there a product that removes the rust, mill scale and oils in one step? Or are there more steps required, I can honestly say most everything I ever read about seems like a perfect world where the only thing the steel has on it is oils. This is not the case in my business. We have a manual spray washing system that we use due to our varied parts, but I can absolutely see the need for a dip tank being a useful tool as well for the smaller parts.

Smut On Titanium Parts   02/01/07
I use a Nitric/HF bath to etch titanium. Afterwards I desmut in 45% by volume nitric acid solution. Recently I have been noticing smut on parts.

Plaforization Performance   12/01/06
We are looking to install a Plaforization system for ornamental iron and aluminum fence. Do you know how many hours of salt spray we can get out of that system?

Inconsistent Results from Passivation   10/01/06
I have passivated the same part, made from 416 SS, in my Nitric/Sodium Dichromate bath a couple of times. On one occasion the parts were attacked and subsequently became scrap. The parts-a few days before and a few days after-were all OK. I document the percentages Nitric Acid on a weekly basis and everything is within specifications (ASTM A-380 Code G). Why would the one batch get attacked and not the others? After having the material analyzed the only major differences in the chemical composition is 0.3% Manganese higher in the attacked parts and 0.25% higher in Copper as well. Could this be the problem? Is improper heat treating the more likely culprit? Any help would be greatly appreciated.

Pretreatment of Multiple Substrates   10/01/06
We are currently coating various substrates for aerospace products with various coatings. We are using a Mil-T-81772 thinner via a wipe method to achieve pretreatment for coating. Our coatings are Chromate primers, TT-E-489 enamel, Epoxy primer and Mil-C-22750 Epoxy topcoat. Substrates are SS 300 series steel, alodined aluminum, anodized aluminum, titanium and magnesium. We are experiencing problems passing dry and wet tape tests. And I have been tasked to get us up to a NADCAP audit ready status. Is there any one method and chemical/solvent that could be used to clean all these situations?

Pros and Cons for Ambient Temp Pretreatment   10/01/06
Our current pretreatment is a heated phosphoric acid three-tank system of acid, rinse and rinse. I am in the process of replacing the system due to worn-out tanks and exhaust systems. In my research, I recently found a "room temperature" strategy for pretreatment. This is of very high interest for many reasons.
Can you explain to me the pro's and con's of room-temperature-pretreatment?

Response to Spray Wand Phosphatizing   10/01/06
Comment: The following was a response from a reader of the column. He elaborated on the question of spray wand phosphatizing. I did note that the pH of the readers cleaning system was far too low and would have to be raised to at least 4.0 to do an adequate job coating the parts.
Additionally, I had also received other feedback on the logic of "top-up" cleaning and "top-down" rinsing. B.D. elaborates on the reasoning. Makes sense to me.

Alodine   08/01/06
We use alodine on 5053 aluminum and use a water based coating. We want to change to powder but we are also having to meet the RoHS requirement that does not allow hexavalent chrome in the alodine. Have you found or know of an alternative to the Alodine that would give good adhesion and good Florida exposure.

Cleaning Welds   08/01/06
I would like to know where I purchase the equipment to passivate weld seams on stainless steel, I do not want to dip the parts, I would like to hand passivate.

Filtration   08/01/06
We are supposed to filter back into the plating tank and I am not sure on how to do the filtration of the solution back into the tank. Should we use a simple carbon cartridge or a wound type of filter?

June Issue   08/01/06
I am a loyal reader of PRODUCTS FINISHING and just finished reading the June issue. You are always very thorough and descriptive. I observed your response to E.P. regarding the phosphate cleaning systems and have some other suggestions...

Pretreatment   08/01/06
I am setting up a new Batch operation and wanted to know which pretreatment to go with. A 3 stage dipping system, or is a 3 stage hot pressure cleaning solution wash, Clear Rinse and sealant? Will the Iron railings benefit from a 3 minute dipping more than a power wash manually?

Phosphate Cleaning Systems   06/01/06
We currently use an iron phosphate one-step cleaner applied manually through a high-pressure wand. The soap solution is applied at medium pressure and a clean water rinse is applied at high pressure.  Most of the material we are treating is hot-rolled, welded and extremely grimy.
Researching, I noticed we were keeping zero controls on anything we were doing so I started from the ground up.

Which Solvents to Use   06/01/06
I'm new to formulating a sprayable solvent-based epoxy paint and my question mainly involves the choice of solvents. Although I know each solvent has its own evaporation rate and solvent power, why do most formulators use more than two types. For example, why would toluene, MEK, MIBK, xylene be used in one paint formulation? Couldn't I get a specific evaporation rate, viscosity, sprayability, VOC's, etc. by just using MIBK and MEK? Or are xylene, toluene or other solvents having more of a major play in a formulation than a carrier?

Hydrogen Embrittlement Problems   04/01/06
We have a problem with hydrogen embitterment.

Iron Phosphate-Rinsing Required?   04/01/06
Must iron phosphate be rinsed before painting? What problems might I have if not rinsed? R.K.

Passivate Using Different Materials   04/01/06
Can I passivate assembled parts with two different materials? One is 304 stainless steel tube and the other is 303 stainless steel solid. I am using epoxy glue made by 3M #2214 regular. I want to know if the acid will create problems to the glue or harm the parts.

USA Made Alternative to Ecophor   04/01/06
I am searching for a U.S.-produced product to take the place of Ecophor A447 product. Do you know of one or can you direct me to someone who may know of one?

When to Change Out Chemical Tanks   12/01/05
How do you determine when it is time to change out chemical tanks. Dissolved soils or just the cost because it is taking so much more product to titrate?

Cleaning Copper Parts   10/01/05
Some of our copper parts, which have been cleaned but not protected by a chemical reagent but cased by vacuum bag, take on a bad appearance after three days. There are some stains and oxidation on the surface. How would you recommend cleaning the copper parts and also how should we package them? What are the normal processes?

Passivate Stainless Steel   10/01/05
I have been told that it is not necessary to passivate 316 S.S., but that 303 and 304 must be to provide a corrosion resistant surface.

Particle Counters   08/01/05
We have seen a number of our customers switch from a washdown weight and visual particle count to a laser particle counter. Do you have any recommendations for suppliers of particle counters?

Metal Cleaning   08/01/03
In our business we sometimes have to send parts (old gas tanks, boat tanks, rusted or heavily scaled pieces, etc.) out to be cleaned, stripped or derusted. We have to send these parts to metal cleaning shops. Who would I contact if I wanted to add this type of business (metal cleaning) onto our existing business?

Cleaning Used Hooks & Racks   02/01/03
In my column for December 2001, I outlined some possible paint stripping solutions for R.R. After that column I received two more suggestions regarding hooks and racks.

Anodizing of Diecast Aluminum   02/01/02
Our company uses a lot of diecast aluminum parts now for agricultural water application equipment such as big gun sprinklers and valves. We generally anodize parts that are going to be in constant contact with the water in order to help protect the aluminum from fast rate corrosion. The dilemma that we run into is two-fold in that with the sulfuric acid anodizing that our vendor uses, the parts come out dark gray and a charcoal residue, which wipes off on everything that it comes into contact, is left behind on the surface. Do you have any suggestions for solving this problem?

Info on PM&M?   02/01/02
I just bought a used sandblasting cabinet and need a manual for it. The name on it is PM&M. Where can I get info on this cabinet?

Industrial Cleaning Techniques   10/01/01
I'm looking for information about scientific groups and firms dealing with the cleaning of rust, cutting oils, grease, etc. from metal surfaces.

Cleaning Chemicals Software   11/01/00
My new process development lab director is in search of software. Where can we look to find software that will assist a process developer in such a way that he can find specific information on what chemistry is used for certain types of applications?