Clear finish that prevents wood darkening?

[Paul Erickson]

I've just completed the inside walls (very crudely) of my shop with plywood, and would like to maintain the light color for the sake of light, but I would like to avoid painting, if possible. The finish I used on the floors is great in terms of durability, but typically the color has darkened significantly, even in the couple of months since I finished it. Does anyone know of a clear finish that will not darken the wood?

Thanks in advance.

cheers, Paul

[Jason Beam]

Putting anything on it will darken it somewhat. Water-based poly does one of the lesser darkening jobs i've heard of, but nothing will leave it completely undarkened. Also, over time, the UV will do what it will - no matter what finish you put on it, the best you can hope for is to inhibit the darkening, but even those UV-protectant finishes eventually allow enough UV throught. How fast depends a lot on how much natural light actually hits that surface, though.

[Sam Yerardi]

Of all the different finishing materials you can use, the following three finish-types work the best: water-born, clear lacquer and wax. Wax is probably the best, but the least protective of the three. I would use either a water-born finish or the lacquer approach. If you choose lacquer, make sure you wear proper respiratory protection.

[Dave Anderson NH]

In addition to Sam's good comments, if you use a wter based finish be premared to either preraise the grain or scuff sand after the first coat to cut off the raised grain. Obviously a second coat would be required as a top coat.

[Cliff Rohrabacher]

MinWax PolyCrylic has no wetting effect.

[Jim Becker]

MinWax PolyCrylic has no wetting effect.

Sorry, Cliff, but I have to disagree with you on that based on my own experiences with both that finish and other water bornes that I normally use. (I only use Polycrylic in a pinch....) Like any water borne product it will slightly raise the grain if it has not been otherwise sealed with de-waxed shellac or pre-wet with distilled water and knocked down after drying.
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To the OP, the suggestions for water borne or lacquer are likely the best options, but you really cannot stop wood from naturally darkening when that is a feature of the species you are working with. (Some woods, like walnut, actually get lighter over time) The natural actions of oxidation as well as UV will conspire against you, although you can slow the UV effect with a UV-protectant, either added to or normally included in the finish. But to avoid the initial darkening, you'll definitely want to avoid an oil-based product. Super Blond shellac is another possible...not quite as "white" as most water bornes, but very light, indeed.

[Robert Rozaieski]

I've just completed the inside walls (very crudely) of my shop with plywood, and would like to maintain the light color for the sake of light, but I would like to avoid painting, if possible.

They are going to darken naturally anyway so no finish will prevent it, only slow it somewhat. I would leave them without any finish at all. Any high gloss finish like laquer or poly is going to shine to the point where you could have glare (unless you rub out the whole wall :eek:). This is almost as bad as inadequate light as it is very hard on your eyes. I like a light dull finish (like flat paint) for light reflectivity but glare reduction. If you don't want to paint, leave it natural without any finish.

[Danny Thompson]

Another vote for Minwax Polycrylic.

On a recent project, I tried some on Makore and maple and was shocked how little change in the color resulted.

Taking Robert's input to heart, satin Polycrylic is fairly low-sheen and would still protect the walls from dirt and stains.