Treating automobile bodies

Claim 1

The method of preparing an automobile body for painting by an electro-deposition process, which comprises the steps of: (a) initiating the growth of a fine crystalline phosphate structure on the exterior exposed surfaces of the automobile body from a multitude of crystal nuclei by spraying said exterior exposed surfaces with a phosphate solution capable of chemically reacting with the surfaces of the body for a period of time sufficient to form said phosphate crystal nuclei, the spray having a maximum droplet size in the order of 100-250 microns and being effected at high energy so as to give an impact velocity on the exterior body surfaces of at least 7.5 m/sec; (b) immediately immersing the body roof uppermost in a tank containing phosphate solution to a level about that of the bottom of the window openings and maintaining a flow of said solution relative to the exterior of the body for a time sufficient to complete the formation of said fine crystalline structure on the immersed exterior sections of the body to give a substantially uniform surface density for said fine crystalline structure of between 10 5 and 10 6 crystals/cm 2 and a coating weight of between 1.5 and 2.0 gm/m 2 ; (c) creating in the interior of the body during immersion a static head of said phosphate solution measured against the normal level of the stream so as to cause a flow of solution from the interior of the body to the outside thereof by flooding solution under pressure into the interior of the body through the window openings; and (d) simultaneously spraying the unimmersed exterior upper portions of the body with said phosphate solution to complete the formation of said fine crystalline structure on the exterior upper portions of the body.

Claim 2

The method of preparing an automobile body for painting by an electro-deposition process, which comprises the steps of: (a) initiating the growth of a fine crystalline phosphate structure on the exterior exposed surfaces of the automobile body from a multitude of crystal nuclei by spraying said exterior exposed surfaces with a phosphate solution capable of chemically reacting with the surfaces of the body for a period of time sufficient to form said phosphate crystal nuclei, the spray having a maximum droplet size in the order of 100-250 microns and being effected at high energy so as to give an impact velocity on the exterior body surfaces of at least 7.5 m/sec; (b) immediately immersing the body roof uppermost in a tank containing phosphate solution to a level about that of the bottom of the window openings and maintaining a flow of said solution relative to the exterior of the body for a time sufficient to complete the formation of said fine crystalline structure on the immersed exterior sections of the body to give a substantially uniform surface density for said fine crystalline structure of between 10 5 and 10 6 crystals/cm 2 and a coating weight of between 1.5 and 2.0 gm/m 2 ; (c) creating in the interior of the body during immersion a static head of said phosphate solution measured against the normal level of the stream so as to cause a flow of solution from the interior of the body to the outside thereof by flooding solution under pressure into the interior of the body through the window openings; and (d) simultaneously spraying the unimmersed exterior upper portions of the body with said phosphate solution to complete the formation of said fine crystalline structure on the exterior upper portions of the body.

Claim 12

The method of preparing an automobile body for painting by an electro-deposition process, which comprises the steps of: (a) providing an automobile body having window openings and interior structure which communicates exteriorally of the body at the bottom thereof below said window openings; (b) subjecting exterior surfaces of the body to high energy spray of phosphate solution for a time sufficient to initiate the growth of a fine crystalline structure thereon which has a surface density of between 10 5 and 10 6 crystals/cm 2 , the spray having a maximum droplet size in the order of 100-250 microns and being effected to give an impact velocity of said droplets on the surface of at least 7.5 m/sec; (c) immediately immersing the body roof uppermost in phosphate solution up to a level below but about that of the window openings and maintaining flow of said solution relative to the body for a time sufficient to complete the growth of said fine crystalline structure with a coating weight of between 1.5 and 2.0 gm/m 2 ; (d) during step (c): (i) creating a static head within said body by flooding said solution into the interior thereof whereby to effect flow of solution from the interior of said body through said interior structure; and (ii) spraying the unimmersed upper portions of said body with said phosphate solution; and (e) recovering the prepared body from said immersion, flooding and spraying thereof.

Claim 13

The method of preparing an automobile body for painting by an electro-deposition process, which comprises the steps of: (a) providing an automobile body having window openings and interior structure which communicates exteriorally of the body at the bottom thereof below said window openings; (b) subjecting exterior surfaces of the body to high energy spray of phosphate solution for a time sufficient to initiate the growth of a fine crystalline structure thereon which has a surface density of between 10 5 and 10 6 crystals/cm 2 , the spray having a maximum droplet size in the order of 100-250 microns and being effected to give an impact velocity of said droplets on the surface of at least 7.5 m/sec; (c) immediately immersing the body roof uppermost in phosphate solution up to a level below but about that of the window openings and maintaining flow of said solution relative to the body for a time sufficient to complete the growth of said fine crystalline structure with a coating weight of between 1.5 and 2.0 gm/m 2 ; (d) during step (c): (i) creating a static head within said body by flooding said solution into the interior thereof whereby to effect flow of solution from the interior of said body through said interior structure; and (ii) spraying the unimmersed upper portions of said body with said phosphate solution; and (e) recovering the prepared body from said immersion, flooding and spraying thereof.