Use interior or exterior clear finish for window trim?

[William.Deans]

Greetings,

Of course most any product would do. If you want the best protection use an exterior oil based polyurethane. Just make sure you have some ventilation.

Hope this helps, William

[Dugie]

Hi,

Now that our new windows are installed, we plan to use a clear finish for the interior pine, such as a satin water-based Urethane.

Is it best to use an exterior grade finish, or is an interior grade fine? I think some rain will eventually wet the surfaces, since we'll probably forget to close a window, or will be hit by a surprise rain storm.

To prevent staining the wood, the contractor said to first apply one coat of finish before filling nail holes with a pine filler. Any other advice is welcome, too.

Thanks.

Dugie

[Dugie]

It does help, thanks. I'll have lots of ventilation, the fumes would be bad.

So for the best, you would use exterior grade, and also an oil based polyurethane. To clarify: Why not Urethane? and why oil, rather than water, based? Not trying to be fussy. Would like to understand. :-)

Dugie

[Savage]

With the high gloss finish urethane/polyurethane, after about two coats, it'll look good - after three, like a polished piece of glass.

It will take many (6 or more from my own experience) to get a decent finish with the water based stuff. The low odour and easy clean up is nice but it tends to soak into the wood without doing much.

Gord

[Amun]

Agree with gord about the water vs oil.

And just want to add that the only usual difference between interior and exterior finishes is perhaps a bit of extra UV protection, usually at about double the price.

"Interior" will be fine, but if price is the same (or cheaper), use the "exterior". (it can't hurt)

AMUN

[Rudy]

Three coats of satin water based poly on our Douglas fir window casing.

600 paper after the first coat. Looks fine R

[Dugie]

My main concern is having a finish which will resist accidental rain water, and also resist fading from sunlight. How long ago did you do the job?

Oh, and filling the nail holes too: did you use commercial filler, or make your own filler?

Dugie

[Rudy]

A year ago..so far so good. The applicator used a high quality stain and rubbed in two coats of that first, We don't leave the windows open if it rains but YMMV

We used a blend of 2 colored wax based "crayons" that matched our color.