etching primer under featherfill
I've been away for awhile ,but had a chance to browse the board tonight .I happened to see this thread and had to respond .
I don't know if ospho is anything like SEM Rustmort ,but if it is ,READ THE LABEL before you use it over sandblasted metal .
Rustmort 's label states that it is NOT to be used on sandblasted metal .
Before using Featherfill READ THE LABEL ,to see if it needs an etching primer under it .In my own experience it needs SOMETHING!! . My personal preference would be PPG Epoxy Primer ,(color don't matter) rather than etch primer on bare metal .
Also ,Evercoat (company that makes featherfill) also makes a product called Slick Sand .I have to tell you that IMO this is a much better ,easier ,and versatile product to use than Featherfill , and I've used both---MANY times .Slick Sand is just as good at filling ,is used much the same way ,and has better adhesion in my opinion.Also, if you read the label on Slick Sand ,it will tell you that it is recommended to be used on bare metal ,without etch primer .Above all other advice I can give you , is READ THE LABELS on anything you use .
Hope this helps . Rick