lacquer problem

[David Houchens]

The check cracks in the photos posted are much larger than any I had, These were 1/8" to maybe 3/4" long. And I don't wet sand between coats if that was what was meant. I was wet sanding before buffing. I am stripping the whole mandolin and will start over.
Thanks to all for the diagnosis. Chalk it up to another learning experience.

[David Houchens]

Sorry no pictures got posted but I think my Shellac sealer was too heavy. Thanks to all who responded

[sunburst]

...I think my Shellac sealer was too heavy...

I've wondered if that is sometimes the problem people are having with shellac as a sealer, but I haven't mentioned it because it is just a guess and could easily be wrong. I spray only two light coats when sealing with shellac and never have sealer-related problems.

[amowry]

To me it seemed like the incompatibility between shellac and the Cardinal lacquer was certainly exacerbated by excessive shellac thickness. It seems to be that Cardinal softens the underlying shellac, which then re-hardens slower than the lacquer does, so when the lacquers hardens and shrinks it pulls away from the wood, especially in inside corners and concave areas. Pulling from inside corners is a problem with a number of finishes and finish/sealer combinations, and I think it's something that guitarmakers often don't encounter because they finish the neck off the instrument in a lot of cases. For mandolins/archtops it can be problematic...

[sunburst]

...when the lacquers hardens and shrinks it pulls away from the wood, especially in inside corners and concave areas...

I have had that happen with catalyzed varnish over shellac, but never with lacquer. (It was the first time I had a finish not adhere well to shellac, previously considered to be compatible with nearly everything.)

[dave vann]

i pursued this a little further and got in touch with Phillip Prichard, Mowhawk Technical service rep. He checked the batch retain on my lot# of the behlen lacquer.
Then he requested a sample of my lacquer. After a month of waiting I emailed Phillip and he revealed that this batch of lacquer was made with 30% more plasticiser than it should. Not much solace, but they will replace the faulty lacquer. The lot# is 2022310 z204. I suggest you check your lacquer and request a replacement if you have some from this batch.

[luvluv_1100]

I am new here, and i bought a mandolin kit. I am trying to get ready to assemble. Can someone be so kind and point me in the general direction on what stain and finishing products to use.. Spray cans vs Brush on.. and what sand paper to use in what order.. Thanks