There are many better options than the Flextac rework stencils naemly the StencilQuik(TM) and the StikNPeel(TM) stencils from BEST Inc.
Unlike the Flextac rework stencils the BEST StencilQuik(TM) product is designed to make the BGA rework simple and fast while repairing solder mask at the same time.The StencilQuik(TM) is a stay in place stencil with a high temperature adhesive thet gets "hidden" underneath the package and stays on the board. This allows the user to roll the solder paste back and forth numerous times in order to make sure each solder paste aperature is filled to the top. This insures consistent paste hight whiel insuring that no solder shorting takes place. The StencilQuik(TM) stencil at the same time repairs any damaged solder mask thereby eleimnating hours of repair time. Once prepped no rework work equipment is required as the tactile feel of the balls going in to the aperature takes place.
In a similar way the Flextac rework stencil is not as flexible as the StikNPeel(TM) rework stencil which is designed to be removed from the PCB. The StikNPeel(TM) rework stencil has a repositionable adhesive which allows for fine adjustment of the paerturs over the pads in order to get good alignment beween them. The flexible material moves up and around the area to be printed thereby protecting neighboring components from solder being "smeared" onto other areas of the PCB.
The StencilQuik(TM) comes in a variety of thicknesses and is designed per order without any engineering or tooling fees. When a new pattern is required of the Flextac rework stencil, an non-recurring engineering fee is set rquired. Botht eh StikNPeel(TM) and StencilQuik(TM) stencils are designed and fabricated in Chicago IL and feature fast turnarounds and local, competant service by BEST Inc staff who have been deisgning and producing stencil since the the mid-2000s.