DSF

I'm finding that on some of my cork backed coasters the cork bubbles up after pressing. Pressing is 180c for 70 seconds. Should I drop the time down?

I expect alas this is due to the quality of the coaster not the method, Are these from a reputable supplier?

pcwizme;152491 wrote:I expect alas this is due to the quality of the coaster not the method, Are these from a reputable supplier?

Yes from one of (I think) the leading two suppliers who exhibit at the big trade shows.

Are you pressing the print side up?
obviously heating the cork directly will cause issues.

Mrteajunkie;152495 wrote:Are you pressing the print side up?
obviously heating the cork directly will cause issues.

Yes print side up

I would certainly give the suppliers a call.

It is moisture. You need to pre-press upside down for 30 seconds then press the right way up.