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Making plastisols are similar to making a cake. The resin in plastisol is like flour in the cake. The plasticizer is like the liquid in the system. Plasticizers are oily to the touch, similar to vegetable oil. The additives, i.e. pigment, filler, puff, etc. are like nuts, fruits, etc. to the cake. These additives offer specific characteristics to the plastisol as with the cake. The point is that this ratio of solids to liquids is specific. If more water, oil, eggs, etc. are added to the cake mix, it takes more time to bake the cake. The same holds true when adding more liquids to a plastisol. You would have to compensate for the extra liquids. It is best to add NA0005 thinner or S.H.A.P.E. to the plastisol when the need to modify arises. Both the thinner and S.H.A.P.E. contain the PVC resin ("binder") which allows fusion to take place. Viscosity reducer is simply a liquid reducer and can alter, if not destroy, the print and fusion characteristics if care is not taken in the addition. Note also that the opacity and/or bleed resistance is lowered when adding any clear plastisol to a colored, all-purpose or low-bleed plastisol.

Pigment concentrates are similar to viscosity reducer in that too much pigment concentrate added to a clear base plastisol would alter the fusion characteristics. Since pigments do not contain binder, there is a limit as to how much pigment may be added to a base (10% to 15% maximum) before curing is altered. This limits the opacity as well. If the mix is not opaque enough there is a tendency to add more pigment, which increases the opacity yet, may destroy the ability for complete cure. Adding more base increases the resin or binder, enabling cure, yet lowers opacity again.
The exception to this is the Rutland Color Boosters, which are pigment concentrates that have binders incorporated in them.

Plastisols are thixotropic. That means the mixture is high in viscosity when at rest and is low in viscosity when shear or movement is applied. Normally, viscosity will build over a period of time but will stabilize. Temperature and shear have the following affects on viscosity.

• As temperature increases, viscosity decreases initially but continued elevated temperature will start early gel causing the viscosity to increase.
  
• As temperature decreases, viscosity increases.
  
• During mixing as friction heat builds, the viscosity decreases.
  
• During mixing friction heat builds up causing the viscosity to decrease initially but over mixing could cause early gel and increase the viscosity.