expedite drying of latex mask

Eric: I�ll pass on the uV and ammonia, also. Thoughts are: 1 You�re correct that the temperature/humidity mix can be a big driver to latex peelable solder mask cure time, but don�t overlook material thickness. Dispensers put material in a very thick layer. Baking a thick layer of the mask seems to make the problem worse, because the mask skins over (cures on the outside) and hinders acceleration of cure times. So, another variable in the process seems to be mask thickness. 2 Mask should be applied in as thin a layer as possible. [We tell people to put-down peelable about as thick as nail polish � it�s getting easier and easier to tell guys that, nowadays] 3 Check your assumption about curing processes as you move through the product evaluation. Humidity (light air), and heat cures could be part of your evaluation matrix. 4 Consider printing your mask, but in doing this, don�t forget to evaluate the ability of the mask to "stand-up" under solder heat cycles. Some peelables get crusty after their first heat cycle. 5 Major types of peelable solder mask types are: * Oven thermal cure peelable - 1 or 2 part PVC (I think), the type screened on by your PCB supplier, who may also use it as a plating or HASL mask. * Ambient air dry peelable - latex (high pH) or synthetic latex (neutral pH and probably preferable). Dispensed. * Ambient air dry soluble - water (warm) or even solvent soluble types. Dispensed or screened/stenciled. * Light cure peelable * Light cure water soluble The light cures may come in long wave UV, or a combination of UV/ visible light cure which is often faster. Both can be dispensed or screened/stenciled. 6 A while ago, Stu Leech posted something on SMTnet about was looking for beta sites for a drying machine.

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