David S. Peterson
Rinsing Difficulties
How helpful would it be to add a rinse aid to our post-process rinses in chromate conversion, and iron and zinc phosphate processes?
Read MoreCitric Acid Passivation
I would like to set up a citric acid passivation line as follows: heated citric, drag-out tank, three cascading unheated rinse tanks and possibly a heated rinse to help in drying. Am I missing any tanks and or accessories that you would recommend?
Read MoreCopper Sulfate Test for Passivated Parts
Why is the copper sulfate test a common test to know if the passivation process is in good quality?
Read MoreStainless Steel Streaking After Passivation
After passivating 347 stainless steel per AMS700 Type VI there is a stain pattern. On inspection at 10x magnification, I see that the surface is pitted. Process steps are alkaline degrease at 140°F, two rinses, final rinse in reverse osmosis water, nitric strike at 5 percent by volume, then two rinses with the final reverse osmosis (water quality 200 ppm). The stains or discolorations are in a straight line pattern. Any suggestions?
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White Haze on Stainless Steel
Has anyone experienced a white haze forming on stainless steel metal surface after cleaning with n-propyl bromide (nPB) solvent?
Read MoreCast Iron, Potable Fresh Water Pump Body
Can you recommend a process to clean rust and “cure” the interior of a pump housing to prevent rusting and not affect the quality of the water?
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Cleaning Limescale from Galvanized Steel
How do you clean white lime scale and rust spots on galvanize?
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Ask The Expert: Clean Paraffin Wax Die Lube
Q. We are a general purpose coating house. Our cleaning line consists of an alkaline cleaner, city water rinse, iron phosphate, sealer, RO rinse then RO halo.
Read MorePowder Coating Pretreatment
How do you recommend we clean a paraffin wax die lube from a cast aluminum substrate?
Read MoreOxsilan Pretreatment Revisited
In my August 2011 column, I responded to a question regarding the benefits of Chemetall’s Oxsilan pretreatment process versus more conventional iron and zinc phosphate pretreatments. Chemetall product manager Gary Nelson has provided further information.
Read MorePretreatment of Carbon Composites
Is there a type of chemical bath or similar option that carbon composites can be processed through to improve paint adhesion?
Read MoreMetal Finishing Standards
What are the intended purposes of specifications MIL-C-10578 and QQ-P-35? Can the passivation be substituted for the phosphoric acid etch?
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