I'm working on a project and we're trying to figure out what the coefficient of friction between steel and latex painted steel. Any help is appreciated!
Is there some means of keeping the steel part from digging into the paint?
If the steel is rough and/or the paint is soft then it more of a soil mechanics problem.
Latex is a form of rubber. So somewhere between steel on rubber and steel on steel. Since paint is relatively elastic, there is a huge variation with pressure and surface roughness. If Google hasn't indexed a test like this, the odds are no one has done it yet.
The OP did not provide enough details of the application. Are they interested in static or dynamic friction coefficients? What are the contact pressures? What is the cured film thickness? As Compositepro noted, "latex" paint is a generic term for water-based emulsion paints containing synthetic binders, and the friction characteristics can vary based on the specific paint formula.
This paper provides some insight on how various factors influence friction coefficients between stainless steel and a latex film.
If you're interested in reading about some basic test work to characterize friction properties of soft rubber materials, take a look at this paper from 1942.
Depends too much on circumstances you have not told us.
Least friction is a smooth stainless steel loosely forced onto a smooth stainless steel.
Painted steel on painted steel (very tight, firm bond with little height or lumps on both pieces of steel) IF the steel is lightly loaded needs to be tested - This because the grip of paint-to-paint is unknown.
Once the paint gets thicker or more uneven, or if the load is great, or is intermittent and frequent, WILL cut through the paint layers quickly. This causes rust (much greater friction, probably two locked surfaces if carbon steel), or the scraped off paint will jam the previously sliding surfaces mechanically.
