|Home » Forums » Professional Finishing » Message||Login|
You are not logged in. Consider these WOODWEB Member advantages:
Alright guys, been awhile since I needed some help but sometimes you have to know when to be the teacher and when to be the student.
I have a S. Bent and Brothers Oak table in my shop. It came in with heat damage on the top with no damage to the pigment.
Might be that a catalyzed Vinyl coating over a non catalyzed Nitrocellulose coating is what caused your problem.Did you remove all traces of residue from the Nitro coating prior to applying the Catalyzed sealer and
Ive seen this happen when the surface was not completely tacked off.
Did you lay out liberal coatings when you applied them or kind of fogged them on?
I used Mohawks Wax Wash after sanding the first time. Dried it and tacked it before spraying on the first coat of sealer.
You cannot spray any catalyzed finish over a non cat finish (well, you might get away with one coat and have it wrinkle on any subesquent coats IME).
General rule is only catalyzed finishes on top of cat finishes - but you can go the other way no issues.
Its the more "aggressive" finish with the hardener trying to lift the underlying finish and once that happens you pretty much have to strip and start over.
I've seen this "alligatoring" in several circumstances in my shop.
It can be an adhesion issue - burnished wood due to oversanding; poor feathering around a chip in the finish; cat- over non-cat, or post-cat over pre-cat; "hot-coating" outside of the window.
Its always a bitch. I've gotten away smoothing it down a little and then misting coats over it. But it takes a long time to build finish in all those crevasses - unless there is some complicating factor, like a faux finish, it takes way less time time to simply sand it off and start over.
I have also gotten away with flattening as much as possible and then applying a barrier coat of de-waxed shellac. Again, you still have the problem of build, and its something you get away with - not really the right answer.
I spray with a firehose, because I like that "fat" look, especially in tinted/opaque finishes. But that has caused problems, especially among the young fellas who want to do like the boss, but don't have the experience to know where to draw the line. This is is especially true in an instance where they might have cut through the existing finish with, say, 150, and then flooded the piece with a post-cat. As Andrew said, the post-cat seeps in those little microscopic scratches and lifts it right up.
Its a frustrating problem, but I agree with Andrew - refinishing might be your best bet. Good luck