Method for enameling the bottom face of a culinary vessel of aluminum or aluminum alloy and a culinary vessel obtained in accordance with said method

DETAILED DESCRIPTION What is claimed is: 1.
A method for enameling the bottom face of a culinary vessel of aluminum or aluminum alloy which comprises applying on said bottom face an enamel slip coating of a conventional type for aluminum or aluminum alloy, heating said layer of enamel slip to a temperature within the range of 50.
degree.
to 95.
degree.
C.
during a sufficient period of time to reduce the moisture content to a value within the range of 0.
5 to 10% by weight, applying a second layer of enamel slip containing between 15 to 40% by weight of hardening agents in the form of fine particles on the first layer of enamel slip before the temperature of said first layer has fallen to a value below about 45.
degree.
C.
, and firing said two layers in order to sinter the enamels contained in said layers.
2.
A method according to claim 1, and applying the second enamel layer by screen-process deposition.
3.
A method according to claim 1, wherein the first enamel layer contains less than 10% by weight of hardening agents.




Description:
This invention relates to a method for enameling the bottom of culinary vessels such as saucepans, frying pans, shallow frying pans and the like of aluminum or aluminum alloy.
Enamels of known types which are used for enameling aluminum or aluminum alloys suffer from the disadvantage of being soft or in other words of affording low resistance to abrasion and scoring.
This disadvantage results from the particular composition of the enamel frit employed, the sintering temperature of which must necessarily be lower than the melting point of the aluminum or aluminum alloy employed.
Some attempt has been made to harden these enamels by adding hardening agents, as has already been described in French Pat.
No.
2,289,627.
However, the present Applicant has observed that the addition of such hardening agents is attended by a major drawback in that it has the effect of considerably reducing the adhesion of the enamel coating.
By reason of the disadvantages just mentioned, manufacturers usually adopt the solution which consists in forming an enamel coating only on the side wall of the utensil whereas the metal of the bottom face of this latter remains uncoated