Degreasing steel

Degreasing steel

I need to make sure the steel is completely free of oil and grease before I enamel it. A good test, to see if it's grease-free, is to run water down the steel and see if the water pulls away from anywhere on the steel surface.

I set up a hot alkali bath (above) using a temperature controlled relay switch to control the power to a hot plate. I'm using a fairly caustic solution of Sodium Hydroxide (NaOH).

Litmus paper test

The Litmus paper test gives this a pH of 11, which should do nicely!

Litmus test gives pH of 11

So I soaked the steel test pieces in the bowl and agitated it from time-to-time

Soaking steel in hot caustic bath.

I soaked for at least an hour but found the pieces still didn't pass the surface water test mentioned above.

I resorted to a well tried method of using a different kind of grease...the sort found around the elbow!

Scrubbing the steel with caustic pumice paste

I'm scrubbing the steel with a cloth and caustic pumice paste. Once done the steel is washed with tap water and put to dry:

drying under a hot box

The 'oven' here is just a large cardboard box positioned over a kiln. In the oven the the steel dries quickly enough not to get rusty.


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