David S. Peterson
Multi-Metal Pretreatment
I need to clean steel, aluminum and steel castings, steel forgings, electrogalvanized and galvanneal sheet, and aluminum sheet metal parts for an e-coat application. Presently, we use Parco 305 (Henkel), but results are variable. The finish on the galvanized parts is especially variable. What chemistries do you have for this range of materials?
Read MoreSoda Blast Question Revisited
In my October 2011 column, a reader had a question regarding a source for Natrium 60 for blasting. Although I could not determine the source, I assumed it had to do with sodium bicarbonate blasting for paint removal. I wrote a bit on that subject and asked the readers to contact me if they knew any more regarding that specific product. Tim Herman of Natrium Products responded with a good overview of sodium bicarbonate blasting. As it turns out, his company offers a product that was likely what the reader was looking for: Natrium 260.
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Ask The Expert: Corrosion Under Powder Coating
Q. We’re powder coating on sheets of cold-rolled closed annealed parts. We found that, after some days, the color is peeling off, and we have found corrosion beneath that. Is there a solution, or should we switch to another process?
Read MoreCorrosion Under Powder Coating
We’re facing problems in powder coating on sheets of cold-rolled closed annealed parts. We found that, after some days, the color is peeling off, and we have found corrosion beneath that. We do a three-in-one cleaning process and then powder coat at our job shop. Our product is an acoustic enclosure of a diesel generator set, so we are using polyester powder for sun resistance. Is there a solution, or should we switch to another process?
Read MoreAdhesive Removal from Aluminum
My company is having problems removing adhesives from aluminum plate that is used for salt spray testing. We are using Alkleen 002L cleaner and Deox NC-620 deoxidizer.
Read MoreInline Aluminum Foil Cleaning
I would like to degrease 0.003-0.010-inch aluminum foil inline before I punch and sheet. Can you point me toward someone who makes this type of equipment and related chemistry?
Read MoreTroubleshooting the Pretreatment and Paint Process
We had finished parts sectioned, mounted, polished and examined under a microscope with the hopes of identifying deficiencies within our coating system that cause premature failure. One of the items brought up are oxides trapped within scratches and scale texture under the e-coat. The substrate is hot-rolled-steel (recycled steel) bar that has been steel shot blasted then put through the standard cleaning process prior to e-coating. Have you ever heard of or seen steel shot blasting driving oxides into small crevices or texturing natural to hot-rolled steel? We cannot seem to figure out why these oxides are still present after shot blast and pickling.
Read MoreTanks for Citric Acid Passivation
We want to change over to citric acid bath passivation. Can we use the same tanks that we use with nitric acid?
Read MoreAluminum Pretreatment for Paint
I am trying to clean and scuff (sand) primed aluminum to prepare for painting. An equipment supplier suggested trying shaved dry ice with a low percentage of particulate like nut shells or baking soda. The dry ice supplier we use does not provide that material. Have you heard of this treatment and do you know of a supplier of this material?
Read MoreCaustic Effect On Zinc-Coated Steel
Can you tell me whether caustic soda will dissolve the zinc coating on zinc-coated steel?
Read MoreCopper Plateback
We have a rack line where we run our zinc and tin plating, and we are noticing when soaking copper parts, in our alkaline soak cleaner, that our steel parts will acquire a dark film on them, when removed from the soak, to go into the electrocleaner. What would be causing this?
Read MorePrecleaning Prior to Ultrasonics
We are cleaning deep-drawn parts that have significant amounts of heavy oil on them when received. Would you recommend some sort of gross oil removal first or just leave it to the ultrasonic cleaner?
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