I've used Laurel Mtn Forge for many rust blue jobs on all kinds of firearms and have never had a problem except for one particular Nazi P-38 frame. It simply would not blue well. The edges would not hold the blue and basically became nearly bare while carding the balance of the frame with 4/0 steel wool. Repeated attemps did no good and I finally had to accept the fact. The slide and barrel of the same gun came out beautifully blued with 100% coverage. Have no idea what was different about the frame.
Anyway, I always degrease with brake cleaner and barehand the parts while carding with no problems on any kind of steel from antique low carbon to modern chrome-moly. For me, the detergent in LMF works very well.
OB
