Telegraphing Issue with High Gloss Laminate on Luan Plywood

High gloss laminates have a tendency to reveal minor imperfections in the substrate. August 26, 2008

Question
I am pressing in a hot press some high gloss laminate onto luan plywood. We are seeing a problem with marks in the laminate. I believe they are telegraphing through the laminate from the plywood core. Does anyone have any suggestions?

Forum Responses
(Laminate and Solid Surfacing Forum)
From contributor J:
Why laun? Why not use better plywood? I think we need some more information. It's hard to make suggestions when we don't know much about the application or the exact problem you're seeing.

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From the original questioner:
We are laminating a high gloss onto luan. With a hot press using PVA glue. We get what looks like an orange peels effect in the laminate that you can see when you get the light shining onto the laminate.

We are using sanded luan and I have re-sanded some with a somewhat marked improvement, but I am still seeing the defect. I have tried several different pressures and have tried cold pressing vs. hot pressing. So far I have not found the answer. Plywood is the desired core because of the weight factor of MDF.

I do not know how much the thickness of glue spread would affect this problem. We are using a black brother glue spreader. I have 35 years of wood working back ground but only one year of pressing plastic laminate.

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From contributor H:
This is the problem with high gloss. If the substrate is not absolutely perfect any imperfection will telegraph. I write this in with every gloss order I get. No matter how hard I try I can’t steer anyone away from the look.

If you have a surface sander I’d go that route. If not, lightly go over the surface with your belt sander. Use a light grit. No matter how hard you try you'll see some imperfection. The idea is to minimize.

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The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor N:
I believe you have inferior laminate. You can prove this by replicating the problem using a piece of glass instead of luan. The glue is the tell. Perfect gloss on the roll can be distorted by installer, equipment, or material. It sounds like everything is ok except the material.

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Comment from contributor F:
We do a lot of hand laminating work and a fair bit of gloss work but would never put gloss over luan. As a rule I'd never apply any HPL to luan. The product that I've seen will delam between the plys at the drop of a hat, or barometer for that matter. Don't know the quality of what you're working with but between the surface imperfections and the unstable edges I'd say you're not loosing anything going to a better substrate. If this is going any place that will ever see moisture you're just begging for trouble.