Caxton-Iseman Capital has tapped UBS for financing backing the $570 million acquisition of Ply Gem Industries, a subsidiary of Nortek. The financing will comprise about $325 million of senior debt financing and $190 million of high yield debt, a banker said. The deal is scheduled to launch in the second half of January. Nortek, owned by Kelso & Co. and management, acquired Ply Gem in August 1997. Ply Gem manufactures and distributes do-it-yourself home improvement products. A Caxton-Iseman spokeswoman was unavailable for comment and Edward Cooney, Nortek's v.p. and treasurer, did not return calls.