Poly not drying

I'm just at the finishing stage of a dining table and having a few dramas with the matt Cabothane polyurethane finish on the top.

The tabletop was sanded thorughly with 120 and then 240 grit before it was sprayed with feast watson sanding sealer (2 coats) and sanded back with 240.

I then sprayed the table top with the Cabothane thinned down by 20% turps with a 1.6mm spray gun.

2 days on there are patches that still haven't dried. They are tacky and you can scratch it off with your fingernails :~.

I rang Cabots and they have said that the maximum you should thin their product is 10% (which isn't stated in any of their literature) but put the lack of drying down to uneven film thickness and to wait for another couple of days for it to dry.

It's got me a bit stuffed. Considering it is supposed to be dry for sanding and recoat in 6 hours and given the fact that the first coat was a pretty thin coat 2 days seems like a long time for it to still be tacky. I'm stating to get worried i'll have to try and sand it all off and start again.

I've used poly for years but this is my first time spraying it.

Any bright ideas about what's going on?

sounds like you put the poly on too thick

Yeah, it seems like that. Maybe it is but i've done a fair bit of spraying and compared to what you'd put on with a brush it was a pretty light coat. The areas that have dried are pretty much what I expect.

Will wait and hope not to break out the sander again....