Baked Oil Finish

Natural aged unfinished iron grate

Recently, some customers have been inquiring about "baked oil finish". This finish is produced by coating iron castings with used vegetable oil and then burning it off in a powder coating oven.

Oxidizing (burning) vegetable oil in the presence of iron at a temperature typically above 300 deg. F but below its flash point will result in a greasy golden brown residue which is a long chain organic molecule. (organic polymer ). Anyone who has inadvertently left cooking oil too long in a hot frying pan will be familiar with this residue as it is exactly the same thing.

The purpose of this finish, ostensibly, is to create a surface that mimics an aged patina finish. This finish wears off over time and is promoted as a way to avoid the "orange rust" phase of the natural patina process.

While IRONSMITH is prepared to provide this finish to customers who demand it, we feel there are some factors that should be taken into account before specifying this finish.
1.Baked oil is not a "Green" finish.
  1. The finish requires energy to apply in the baking process. (More than a typical powder coat application.) That energy would typically be supplied by natural gas.
  2. The burn off of the oil produces pollutants of several kinds including green house gasses (CO2, CO,) and PM10 class particulates (10 micron particulates known to cause health problems and restricted by the EPA South Coast Air Quality Management Board etc.). One can see this for one's self in the smoke from an over heated fry pan of oil.
2. Baked oil has no track record in the field

To date we know of no extended exterior field trial of this type of finish.

We have begun some trials ourselves with mixed results to date. The finish will prevent "orange rust" from forming on the grates but where it wears off or is thin localized areas of rust appear and they will generally be orange at first. The organic polymer may get sticky in intense summer heat causing dirt to adhere.

3. The end result is the same.

 

 Over time both an unfinished grate and a "baked oil finish" grate will look the same. We feel this process, then, has no real benefit but has real economic and environmental costs.