Introduction and question

[McCreed]

Welcome Jim.
Unfortunately I don't have any clear-cut answers for you as it could be a myriad of things that are the cause. Sometimes things like bubbling, wrinkling happen inexplicably. I experienced this with two allegedly compatible products from the same manufacturer.

This may not explain your bubbling, but sanding timber to 800 is way too fine, and can cause issues with adhesion. Fine grits like 600, 800 begin to polish the surface instead of abrading. The primer needs the microscopic abrasions for "mechanical bonding" (in simple terms "stick to"!). Again, this does not account for the bubbling, it would be more likely that you'd experience the paint lifting or peeling. It's recommended to not go finer than P240 (or 220 if in the US) for preparation before painting timber.

Did you clean the bare wood with metho or naptha before applying the primer? There may have been traces of machine oil or other contaminant on the wood from the manufacture. Hard to say, I'm just throwing things out there.

As for "Sorry the post is quite wordy"... you obviously haven't looked around the forum much (or read some of mine )... your post is brief by comparison!

[Jim De Bressac]

Thanks McCreed

I feel better about being verbose !!

We didn't put any metho or such on as the grain hadn't raised. Good point about too fine a grit and I'll note that for next time.

The bubbling only happenend after the wet and dry process and only around the penetrations so I am assuming water has crept under one or some of the layers of primer, paint or clear coat. I have sanded the clear coat off and starting again. I have sealed the small screw holes with pva glue and coated the insides of the large holes with pva as well ( and crossed my fingers ).

I'll let the group kmow how this goes.

Thanks for the support