Therma-Tru SHOP 3 Door Preparation - U1 Revised - Manual (Page 9)

Door
Preparation
Shop 3 2014 (U1 REVISED) 3.9
Door Slab Resizing
Apply Adhesive
Fully coat inside skin surfaces of rail pocket.
Use plain, no-kerf rails at top of door, or
kerfed rail with kerfed edge pointing
inward (not showing).
At bottom end, place rail in pocket with
kerfed edge facing out.
Note: For 20-minute steel fire doors,
only the bottom rail may be replaced.
The replacement rail must conform to
the specifications in the applicable
fire door listing report.
Insert Rail
Mix Adhesive
Use a fast-setting epoxy.
Mix thoroughly before applying to
door skins.
Note: For 20-minute steel fire doors,
only adhesive(s) specified in the
applicable fire door listing report
may be used.