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Archive | May, 2016

Stainless steel and heat tint

Belfast-20130415-00284

If you’ve ever overheated your stainless steel cookware (like almost all Revere Ware) you’ve seen that rainbow tint discoloration that stainless steel can take on. This isn’t something you can simply wash off.   This discoloration is called heat tint.

Stainless steel works (keep from rusting) due to the addition of small amount of chromium int the steel mixture. (Note that this is a type of chromium that the body needs in trace amounts, not the hexavalent chromium of the type featured in the move Erin Brockovich.)  The Chromium oxidizes and forms a thin layout on the outside of the stainless steel which keeps the iron from rusting.  The nice thing about stainless steel is that this layer is self repairing; if you damage it, more chromium is exposed to air and oxidizes to form a new protective layer.

However, it seems that under high heat, parts of the stainless steel can form a thicker chrome oxide layer. Chrome oxide layers of different thicknesses will show different colors.

In short, the rainbow tint is completely harmless, if not annoying.  The best suggestion we’ve seen to remove it is to use a stainless steel cleaner like Bar Keepers Friend to polish the outside of the cookware.

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3D printing a new tea kettle trigger

We’ve completed our first 3D printable design – a trigger for the larger 3 1/2 (or so) quart Revere Ware tea kettle.

trigger_rendering

Here are the old and new trigger side-by-side:

old_new_trigger

We gave the new trigger a more curved end as we felt that the original allowed the finger to slip off too easily.

The only material available for our printer that matches or exceeds the temperature resistance of Bakelite is called Z-GLASS and is semi-transparent.  While the trigger won’t win any beauty contests (it is a bit of a rough finish due to the nature of 3D printing) it is quite functional.

Here it is on a kettle:

trigger_on_kettle

If you have a 3D printer that can print to a material that has a deformation / deflection / softening temperature (the point at which it will irreparably bend) greater than 350 degrees F, you can print these yourself.  Here are the Solidworks and STL files.

If you would like to get one of these triggers, please contact us.

Update: Unfortunately, despite the temperature rating of the material we used, the trigger started softening up pretty quickly when we tried it out on the stove.  We are still looking for a material that can be 3D printed and will withstand the temperature.

 

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