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

Reverse Current Cleaning   12/01/08
I am interested in building a reverse current tank but I have zero experience using this type of equipment. I was wondering if you might have a contact that could assist us in building one of these tanks at our facility in Southern California.

Chlorinated Paraffin/Vacuum Heat Treating   10/01/08
I have a suspicion that the metal stamper is not removing all of the chlorinated paraffin and that the chlorinated paraffin is having an adverse effect on the steel parts during or shortly after the vacuum heat treat. Considering that the heat treatment is being done in a vacuum, I don’t think any paraffin is being decomposed, but rather cracked into smaller alkanes and alkenes. What is confusing me is the apparent rust pattern that develops on these parts. Can you advise me on this?

Pitting of 7075 and 2024 Alloys   10/01/08
I would like to know more about the pitting problems in 7075 and 2024 aluminum alloys. We currently make anodized parts from both alloys and on occasion we see pitting after cleaning. I have recommended RO water in the tanks and DI water in the seal tanks.

Stripping Nickel from Inconel 718   04/01/08
Could you please advise me of the best way to strip sulfamate nickel off of Inconel 718 base material? Is there a risk of damaging the part if it is stripped in 50% nickel due to the high nickel content of the base material? Any advice would be greatly appreciated.

Passivation of 17-4ph Stainless   02/01/08
In response to your Article "Passivation before Heat Treatment" in October 2007: Your second paragraph states "If the atmosphere in the furnace... etc". Stainless steel should never be heat treated in an atmosphere. The only heat treat/anneal that should ever be done to any and all stainless steels should be done in a vacuum environment. If it's done in an atmosphere, any contaminants (steel) will attract to the stainless steel and will cause corrosion.

FRP Parts Washer   04/01/07
I am considering the use of a 5 stage part washer constructed from FRP (Fiber Reinforced Plastic). Do you or know anyone who has any experience with a washer constructed from this material? It is intended to wash mild steel sheet metal parts.

Passivation Problems   04/01/07
I am having a problem with parts passivated in citric asic. They are 303ss and passivated for 30 min. My end user is sending them out for a salt spray test and they are failing.

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.

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.

Evaluating Acid Concentration by Titration   12/01/06
We have installed a vibratory clean/deburr system that uses stainless media and sulfuric acid to clean copper and brass brazed parts. When performing a titration to evaluate the acid concentration we get a coalescing of black material in the solution as the end point is approached. This makes it difficult to observe a pink color shift. It also seems to slow the reaction. Does anyone have an idea what this substance may be? Any suggestions?.

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?

Removing Oxide Coating From Titanium   12/01/06
I want to find how would you remove the bluish color from the surface of titanium products?

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.

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?

Cleaning of Surfaces   07/01/06
I need good information on the cleaning of surfaces. Can you recommend some information sources?

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.

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

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?

Alkaline Solution   02/01/06
I work at a carpet cleaner. We also clean tile. Recently we spilled a little of our alkaline solution onto a customer's steel refrigerator door. I first told the customer to use the back side of a Brillo pad to kind of scratch the steel door to match the patterns, but that hasn't worked. Do you have any recommendations on what I could use to get rid of the etching spots made by the alkaline solution? We use an acid cleaner as well but I'm not sure if the acid cleaner that we use would change the pH balance enough to counter the alkaline.

Dull Polish in 440c and 420B NIMO   12/01/05
We are ball making people. We find dull polish problem during passivation of 440c and 420b nimo steel.

Phosphating on Differing Surfaces   12/01/05
Is a smooth surface better for phosphating or a rough one? We are thinking of moving to a steel media in our mass-finishing equipment instead of the ceramic media we are using now. There is no question the steel media provides for a better finish but will it affect the phosphating process negatively?

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?

How to Clean and Preserve Copper Plating   11/19/04
We have a little problem with copper plating on torlon plastic parts. The plating seems to be working fine. The problem arises in storage when after time we begin to see small spots or discoloration on the plating. Our customer will reject the parts for having any type of imperfection...

Powder Coating Over Finished Chrome Parts   09/25/04
We have a four-stage washer with a first-stage iron phosphate wash heated to about 130°F, two fresh water rinses and a final seal rinse. Sometimes we powder coat over new parts that are finished in chrome...

Local/Spot Passivation   08/01/03
I have been asked to create a validation protocol for localized/spot passivation. Our products consist of surgical instruments for the orthopedic industry. We use mostly 17-4 SS but have also used 440C. Occasionally, parts must be reprocessed requiring some additional cleaning around the reworked areas. How should I approach this validation?

Referral   08/01/03
I was wondering if you know of anyone who does barrel electropolishing of small parts? Thanks for your time.

Hard Chromium Plating and Fixturing   06/01/02
I have recently been put in charge of our hard chromium plating operations. I am new to electroplating and want to learn more about the chromium plating process. I want to learn how to do it right as opposed to the "we have always done it this way" approach. Can you suggest some books and references I can read to learn more about the hard chromium plating process?

Stains on Plated Parts   06/01/02
I work for a plating company that deals with plastic plating. We have a problem with water stains on parts after they come out of our dryer. After going through the decorative chrome, the parts go through four rinse tanks. The last two are DI water, yet we still have some stains. Is there anything else that we can do to avoid these drip stains?

Removing Welding Smut from Aluminum   11/01/01
We are welding 6063 aluminum extrusions and are looking for an efficient way to remove the welding smut from the parts. What do you suggest? R.W.

Cleaning Magnesium   10/01/01
What is the recommended chemical cleaning process and composition prior to electroless nickel plating for magnesium?

Reverse Current Cleaning   02/01/01
I am the electroplating manager at a company that makes connectors. All of our parts are made from raw metal stock (copper, nickel-copper, etc.) on screw machines. The problem we have is we must clean the parts before plating them (remove the cutting oils and grease). We have used chemical cleaners, anodic cleaning and reverse current cleaning. What I am looking for is as much information on reverse current cleaning. This process seems to work the best. In the current process, we are using 2-5 min at no more than 4V. Can you shed anymore light on this subject? Any information would be appreciated. Also, are there any web sites that would be beneficial to look at on this subject?

Smut and Desmutting   02/01/01
I am new to this industry and have heard about smut and desmutting operations. Can you please give me a definition of smut? How is smut generated in the process of anodizing? What is the desmutting operation? I would appreciate any references for further technical reading.

Zinc Phosphate Sludge   09/01/00
We run a zinc phosphate spray coating line where mostly mild steel is treated. Since the startup of the line, we have experienced problems with excessive sludge buildup.