Screen Printing Forum

hi --

could someone please give me some info on the following questions:

1. with dual cure emulsion, does the "dual cure" aspect have anything to do with the types of ink you can use with it (plastisol, solvent-based, etc.), or does it only deal with the way the emulsion hardens? can typical dual cure and regular diazo emulsions be used with both plastisols and solvent-based inks? thanks!

2. i have a very basic understanding of mesh counts and their uses, but yesterday ran across a webpage about fabrics, at pocono screen supply (http://www.poconoscreen.com/tips/fabric.html) that was confusing. for a list of various applications, it had a chart with headings "mesh," "count," "inch,"
and "(cm)." for example, for printing posters with uv inks, it had mesh: 380, count: (150), inch: 460, (cm): (180).

this has thrown me for a loop. i've generally understood that the mesh count is the number of threads per inch in the fabric, and is pretty much indicative of how fine a detail you can get with it and how tough the ink is to force through it. can anyone please explain wha the other figures mean?

thank you!

Hi Chunk-
Basically the term "dual cure" relates specifically to the type of sensitizer system that the emulsion uses. dual cure products usually are purchased with the emulsion partially sensitized, most often with a photo-polymer sensitizer and the end user adds the second (thus dual) sensitizer to the product. Check with the manufacturer of the whatever emulsion you choose regarding the best application for the emulsion formula. Some emulsions are designed specifically for plastisol inks that do not require a high degree of solvent resistance and will be less likely to break down if you let the plastisol sit in the screen for extended periods. Other formulations are designed to be water resistant for H2O containing ink formulas; provide higher resolution and thinner stencils for UV printing; and higher solvent resistance for higher solvent containing inks, like vinyl inks.

Regarding the mesh count question, it is common for mesh suppliers to provide a metric cross reference to the US standard of tpi (threads per inch). The cross reference refers to the number of tpi -vs- the count of threads per centimeter. Typically, when using UV inks, you should choose a higher mesh count in the 390 tpi and up to 500+ depending on the ink manufacturers recommendations. Check the ink data sheet for the ink makers mesh recommendation and stick to their recommendation. If you experience any cure problems with the ink, the first question they will ask is what mesh count you are using.

Hope this helps.