  In this paper, we introduce a horizontally-oriented, photophoretic `boat'
trap that is capable of capturing and self-loading large (radius ${\ge}1$
$\mu$m) solid gold particles in air for more than one hour. Once trapped,
particles are held stably, even as the trap is modified to scan axially or
expanded to a larger size to increase the capture cross-section. We
theoretically present and experimentally demonstrate each of these affordances.
We describe the utility of such to investigate large, metallic, and plasmonic
particles for display applications.
