letter 53536

What causes Manganese Phosphate to not adhere? [Illinois] 

November 4, 2009

Our company has received several deliveries of weldments from an outside vendor. During the Manganese Phosphate process the second set of weldments coated everything except the welds. I suspect that the weldments were welded with Stainless Steel filler. Are there any other fillers that will not accept Mn Phos?

Randy Hilgen
process planner - Peoria IL. USA

I will guess that they did a chemical cleaning that did not touch the oxide layer on the welds.
If this is so, consider grit blasting the entire unit or mechanical cleaning of the welds prior to chemical cleaning.

James Watts
- FL