  We present weak lensing mass estimates of seven shear-selected galaxy cluster
candidates from the Deep Lens Survey. The clusters were previously identified
as mass peaks in convergence maps of 8.6 sq. deg of R band imaging, and
followed up with X-ray and spectroscopic confirmation, spanning a redshift
range 0.19 - 0.68. Most clusters contained multiple X-ray peaks, yielding 17
total mass concentrations. In this paper, we constrain the masses of these
X-ray sources with weak lensing, using photometric redshifts from the full set
of BVRz' imaging to properly weight background galaxies according to their
lensing distance ratios. We fit both NFW and singular isothermal sphere
profiles, and find that the results are insensitive to the assumed profile. We
also show that the results do not depend significantly on the assumed prior on
the position of the mass peak, but that this may become an issue in future
larger samples. The inferred velocity dispersions for the extended X-ray
sources range from 250-800 km/s, with the exception of one source for which no
lensing signal was found. This work further establishes shear selection as a
viable technique for finding clusters, but also highlights some unresolved
issues such as determination of the mass profile center without biasing the
mass estimate, and fully accounting for line-of-sight projections. A follow-up
paper will examine the mass-X-ray scaling relations of these clusters.
