The following information accompanied stocks donated to the Bloomington Stock Center by Nick Brown, University of Cambridge.
Because Fit1 and Fit2 are at least partially redundant, individual mutations in Fit1 or Fit2 do not produce blisters in homozygous wing clones produced by mitotic recombination, but blisters are produced when 3L chromosome arms carrying Fit1 and Fit2 mutations are made homozygous in wing clones. 
To screen for other mutations involved in wing blister formation, Fit283 P{FRT(whs)}2A chromosomes were mutagenized with EMS and 3L chromosome arms were made homozygous in the presence of a vestigial-GAL4 insertion and a UAS-FLP insertion to look for wing blisters. The following mutations were isolated:
hobC55         W2218X
hobC236       W1985R
ClC-cA27      L756X
ClC-cB87      W338X
Rcc1A47       T266I
Rcc1C226     T266I
Usp5A10       G781N
Usp5C235    C207Y
sflA7 Q426X
sflA84           V477E
sflC1 H993R
gigasA25       C480Y and Y1662X
gigasC28       V1602Q
CG1136C227 K80X
CG1136C245 Q25X
rheaA16
rheaA109
rheaC63
rheaC110
rheaC130
rheaC208
Note that Rcc1A47 and Rcc1C266, although identical, are independent mutational events.
In addition, two mutations in an unmapped complementation group were isolated. The locus was named 'crisp packet' (cpkt) as wings with clones induced by vg>FLP look like a crumpled-up potato chip/crisp packet. The alleles are:
cpktA42
cpktC249