We have been noticing small checks and lifting in fumed larch veneer on fire rated MDF. There is no finish on it yet and we are reluctant to begin. We had a similar problem with fumed oak lifting and splitting off the substrate. Is this a common problem with fumed veneer, or a manufacturer defect? They always claim that the glueup was perfectly orchestrated and it must be us. The panels are still raw so I find it hard to believe.
From contributor C:
There are a ton of things that could do this, here are some:
* M/C of the veneer was high
* M/C of core too high
* Too much heat at pressing
* Not enough heat at pressing (residual moisture)
* The core outer surface is loose
* The core did not bond to the veneer (FR care is tough)
* FR core works best with UF glue, PVA is tricky
This is general. I have never worked with fumed larch, but it may have properties that require special attention.