Method for sealing a fastener
A method for sealing a fastener employs a mold which provided with an inlet port for molding material. The mold is then positioned over a fastener and the mold is sealed against a structure. A molding material is then injected into the mold. The mold is then removed to leave an in-situ molded cap formed over the fastener and sealed to the structure.
1. A method for sealing a fastener comprising the steps of:
providing a mold having an inlet port for molding material;
positioning the mold over a fastener;
sealing the mold against a structure;
injecting a thermoplastic elastomer (TPE) molding material in a plastic state into the mold to fill the mold with any overflow routed through an overflow port, said TPE selected from a set of thermoplastic polyether-ester block copolymers, thermoplastic fluoroelastomers, Polyarylsulphones (PSU) or polyphenylsulfones (PPSU);
cooling the TPE yielding a preliminary cure without chemical reaction; and,
removing the mold to leave an in-situ formed molded cap over the fastener and sealed to the structure.
2. The method as defined in claim 1 wherein the molding material adheres to the fastener and the structure.
3. The method as defined in claim 1 wherein the mold provides a sealing circumference on a surface of the structure around the fastener, said molded cap sealed to the surface within the sealing circumference.
4. The method as defined in claim 1 wherein the mold is formed from Polytetrafluoroethylene (PTFE).
5. The method as defined in claim 4 further comprising spraying a release agent into a cavity in the mold prior to positioning the mold.
6. The method as defined in claim 1 further comprising applying a surface treatment to the surface prior to positioning the mold.
7. The method as defined in claim 1 wherein the step of injecting molding material is performed with a handheld hot melt gun inducing the plastic state in the thermoplastic elastomer.
8. The method as defined in claim 1 wherein the steps of applying the mold and sealing the mold are automated.
9. The method as defined in claim 1 wherein the fastener comprises an array of fasteners and the step of positioning the mold comprises positioning the mold over the array of fasteners.
10. The method as defined in claim 6 where in the step of applying a surface treatment comprises applying a primer over the surface within the sealing circumference.
11. The method as defined in claim 6 where in the step of applying a surface treatment comprises applying an adhesive over the surface within the sealing circumference.