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Is Koa considered an oily wood?
I am having crazing (alligatoring) and adhesion problems (I have never had this problem before with Mahogany, Rosewood, Ebony or Spruce) on some Koa ukes. Sprayed 2 coats of 2lb cut flake shellac. StewMac waterbase filler, sanding sealer and top coats.

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Formerly know as Mandodiddle.

With all that stuff on top of the wood .. its not the wood. And no, koa isnt oily ... how does the waterbase filler sit on top of the shellac ??? I woudl think you fill first, then shellac coats then tiopcoats .. no sanding sealer requried. That stuff might be your issue ...

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Tony,
Thanks for the reply. I'm not sure I follow you --- "How does the filler sit on top of the shellac?"

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Formerly know as Mandodiddle.

Well you say in this order .. 2lb shellac, then filler, then sanding sealer then top coats ... so I am asking how well does the filler sit on top of the shellac (or am i misinterpreting your order of ops there) ... does it flow out evenly ??? is there a bonding issue there ???

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Tony,
It does seem to flow just fine. I am thinking that this interface between shellac and filler is the area of the adhesion problem.

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Formerly know as Mandodiddle.

Koa isn't an oily wood but if it were, shellac would seal it. Your problem is incompatibility between
the shellac and the filler, I would think.

Why use sealer on top of shellac? What kind of sealer and how much of it? And what is the top coat? Sounds to me like too many layers underneath. It's not the koa.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Yep, too much fat under the lean. All that soft stuff under your lacquer is the problem.

No.