"Plates for eating slowly" or "Heat Retentive Plates" are already on the market, however any person with some knowledge in pottery can make his/her own plate. This type of plate typically need only one minute preheating in a full size microwave oven and remain still hot after 30 minutes to keep food warm.
"Heat Retentive Plates" were developed originally as: "gourmet plates"; they were conceived simply to enjoy hot food, however people has found many other applications for them, such as:
"WLS Plates", this means that weight loss surgery patients who need to eat slowly (Particularly after the operation), are using them to keep their food warm.
"Caregiving plates" for the elderly, Alzheimer's patients and people with mobility problems due to: Stroke, Parkinson's, ALS (Lou Gehrig's disease) and other neurological problems.
The plates are very simple to make; they only have 3 components which can easily be made by any person with basic skills in pottery or any company that manufactures normal plates .
1Using the Image as a guide, make original models of the components by any well known method (Basic knowledge of pottery is assumed). Remember that ceramics shrink when fired; so take that into account when making your models. You can make "Heat Retentive Plates" in practically any shape but it is preferable that the heater is round as well as the cavity that encloses it. The key is to enclose the heating element or heater in a tight cavity and making minimum contact with the walls of the cavity. The radius of the heater should be about 3/8" (about 10 mm) smaller than the diameter of the cavity.
2Using your model, make molds out of "Plaster of Paris" there are many books on the subject of molding ceramics. A practical alternative is making the mold out of silicone RTV; this method allows to reproduce very intricate or complicated originals and you can find videos about the subject on You Tube.
3Make the plate or upper component which can have "corrugations" or "circular reinforcements as shown; (This is only a possible configuration of the plate.
4Make the base or lower component as shown; Important: it does not have a "dry foot", the part that seals with the plate goes unglazed and the base is fired upside down when glazed.In this particular case the base has also corrugations but they are optional.
5Make a heating element using red earthenware and mixing 15% of iron filings thoroughly by "wedging" or any other mechanical means such as a pugmill; the heater is not glazed and it is fired at cone 04 (The upper and lower component firing cone depends on the clay used, also follow the recommendations of the glaze manufacturer regarding to firing instructions.
6Once you have the 3 components ready assemble them upside down using a waterproof glue.
Questions and Answers
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- The heater needs to be glued in place with high temperature epoxy; the area where the heater is glued and the joint must be unglazed. You should know also that there are nowadays many high tech adhesives available; I'm sure you know that even airplanes are being assembled using adhesives.
- Use lead free glaze approved for use with food; there are some glazes that are for use only with decorative ceramic objects.
- The plates get very hot with typically just one minute preheating; handle with care; however you can handle the plates safely by the rim. Do not overheat them, one minute is enough (Make sure the heater is separated at least 3/8" (Approximately 10 mm. separated from the side (Vertical) wall of the cavity).