Use interior or exterior clear finish for window trim?

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
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Dugie wrote:

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
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fine?
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
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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
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finish
it
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
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Three coats of satin water based poly on our Douglas fir window casing. 600 paper after the first coat. Looks fine
R
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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
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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.
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