strike through dull varnish

[padilla]

i am having some trouble with strike through dull varnish piling on my coater blanket. are there any suggestions

 

[Bob Peterson]

Check the following:

Coating viscosity. Should be 17-19 with a #3 Zahn cup.
Check coating blanket squeez.
Increase coating film thickness.

If none of the above address the problem, the varnish is probally setting up too fast. Add 2% or 3/8 ths of an ounce per pound of linseed oil to the varnish. This will slow down the set speed. Be carefull as to how much you add as it will tend to make the varnish glossier.

 

[padilla]

thanks for the suggestions. i have found that a viscosity higher than 13-15 secs won't allow the strike through to workas well as it should. pressure is correct costing thickness seems to help. do you think some tack rducer in the varnish may help instead of linseed oil?
thanks

 

[CKL]

Strike Through

Strike Through

Check to see which blanket surface you are being supplied with. Some are more likely to take ink/varnish. Each manufacture may call it something different. Cast, ground, buff, polished. Make sure you use a 3 ply not 4 ply.

 

[Bob Peterson]

If you want to try and reduce the tack of the varnish I would recommend a petroleum solvent i.e. Magie 52 or 60 Oil. Ask your ink company to supply you with this reducer.

 

[Indexx Printing]

thanks for the suggestions. i have found that a viscosity higher than 13-15 secs won't allow the strike through to workas well as it should. pressure is correct costing thickness seems to help. do you think some tack rducer in the varnish may help instead of linseed oil?
thanks

Since tack reducer has some linseed oil or other vegetable base it will help. We are running a 6 color Heidelberg CD-102 with a coater. We run Nicoat 2120 gloss coating and Hostmann Steinberg Strike through varnish. We run tegra jelly reducer. We have found that turning the sweep down on the coater and pumping the varnish helps. It also helps to run as little water as possible. We run Allied All-Star G2 at 3.5-4 oz. per gallon and nothing else and we continue to see our water sweep speeds in the upper 20s to low 30% range. Hope this helps you.

Todd

 

[earlhubbs]

The best combination that I have seen is the Nicoat 2710 with OVI Contrast Dull Varnish. The cleanest running Coater blanket is the Folacoat polyester. Because of its smooth surface the varnish will not build up like a rubber coater blanket. Let me know if you need contact info on any of the products.

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