Burnishing Compound to Hurt Liner

Question:

We have a seven cu ft tub style vibratory finisher used for steel ball burnishing. Last year we relined it, and the salesperson told us that we had to use the company's compound or the warranty would not be honored. Can a burnishing compound hurt the liner? C.P.

Answer:

I am disappointed to learn that the questionable sales tactic you refer to is still being used. Almost all mass-finishing machines today are lined with polyurethane. This has been common practice for more than 20 years. I remember the old natural rubber liners that were damaged by mineral spirits used in automotive-parts reconditioning, but all those machines have long since been changed to polyurethane. Polyurethane can withstand any compound commonly used for mass finishing. I spoke with a very experienced lining manufacturer, and he never heard of a mass-finishing compound that will hurt polyurethane. This even includes the strong compounds used in chemically accelerated finishing. If there are any compounds out there that should not be used with polyurethane liners, a bigger concern than lining damage will be operator safety and environmental impact.

Polyurethane linings can be hurt with extremely abrasive, or sharp, objects. An example is part-on-part finishing of heavy, sharp edged stampings or forgings. Some of those applications use ceramic, or steel alloy linings that are substantially harder than the parts.