14 CFR § 65.104 - Repairman certificate - experimental aircraft builder - Eligibility, privileges and limitations.
(a) To be eligible for a repairman certificate (experimental aircraft builder), an individual must -
(1) Be at least 18 years of age;
(2) Be the primary builder of the aircraft to which the privileges of the certificate are applicable;
(b) The holder of a repairman certificate (experimental aircraft builder) may perform condition inspections on the aircraft constructed by the holder in accordance with the operating limitations of that aircraft.
The following state regulations pages link to this page.