Gloss UV problem

[JBP]

Hi

We are a magazine printers using Heidelberg XL106 presses and conventional 4 colour process inks.
All our covers that have a treatment on are sent to a third party for it to be applied.
Recently all gloss uv treatments have come back to us looking normal but if you even lightly scrape the uv with a fingernail it scrapes off.
Nothing has changed with our presses, inks, chemistry or procedures and the company that do the gloss uv says nothing has changed their end either.
Has anybody had experience of this and knows the likely cause?

Thanks

 

[Hman1956]

HI JBP,
we have had the same problem on and off for years. below is a list of thing we try to control, and it helps.
stay away for inks that stay open in the fountain for a long time.
the more moisture in the shop and paper/board the better you will be.
if you're putting AQ coating on the work inline......use a smaller BCM roller and a primer.
if you see just a faint image left on the sheet, like a staining from the ink, it is the ink film the is failing not the coating.
do a K&N test on the board, if the board sucks the wet ink into it self, there will not be enough binder left in the ink to hold on the pigment.

without see what you have going on it's to tell just where the failure is.

BTW what board are you using, we had a lot of problems with Clearwater and moved to IP