../catalog_98/Techniques

 Softening PMC-121/50 & PMC-744 Using ‘SO-FLEX’

 Using ‘SO-FLEX’ By Weight . . . For best results, you should use an accurate scale to properly use ‘SO-FLEX’ with PMC-121/50 or PMC-744. ‘SO-FLEX’ should be weighed and must be thoroughly mixed (at least one minute) with the appropriate amount of Part B before combining with Part A.‘SO-FLEX’ is a softening agent that lowers the cured durometer of a variety of Smooth-On polyurethane products. The charts below indicate the effect ‘SO-FLEX’ has on full cured (7 days) PMC-121/50 and PMC-744 when added as a percentage of the total mix.

Parts By Weight

Part "B" + "SO-FLEX" (mix well) + Part "A" = Hardness*
50 0 50 50
50 20 50 43
50 40 50 35
50 50 50 30

*Shore A hardness after 7 days.

Using SO-FLEX by volume with PMC-121/50 . . . if you want to add SO-FLEX by volume instead of by weight, you can do so by measuring out equal amounts of parts A, B or SO-FLEX. As indicated above, this will result in a cured Shore A hardness of 30.

Softening PMC-744 with ‘SO-FLEX’

Normally, PMC-744 cures to a hardness of Shore A 45. PMC-744 can be made softer and more flexible by adding different percentages of ‘SO-FLEX’ as indicated below.

Parts By Weight

Part "B" + "SO-FLEX" (mix well) + Part "A" = Hardness*
50 0 100 45
50 20 100 40
50 40 100 35
50 50 100 30

*Shore A hardness after 7 days.