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Choosing a good exterior finish for new double glazed wooden windows9/7
I'm making a series of awning style windows for my new shop. This is my first set of wooden windows that will actually operate and they're also my first ones that are not single pane but instead use double pane sealed units. Fixed single pane was certainly more straightforward but sense its for myself I'm willing to experiment a little.
Anyways, I have a custom cabinet and furniture shop and am not concerned about the actual woodworking, it's the finishing that has my head spinning. I have a full AAA booth, and almost everything in the shop rolls through there. However on these windows I want to use a brush-on finish for the simple reason of future maintenance .
The windows are being built entirely of Douglas Fir which will get a waterbased satin poly on the inside. I WANT to do the outside in a linseed oil paint for the main reason that the stuff doesnt peel but instead slowly fades, which makes touch-ups every few years very easy. My problem is that the linseed oil paint manufacturer says that the linseed oil will react with the sealant material in the window glass assembly.
"Can I use your paints if I am having new sealed, double-glazed window installed?
Yes, but it is not recommended because the linseed oil can destroy the silicone seal in the double glass. It can be done, but it is tricky. There is a way of sealing the glazing grooves with shellac, preventing the oil from getting into the seals. This is the only situation we have come across where a modern product is not completely compatible with linseed oil."
I live in the very wet Canadian Pacific Coastal area so I want to prefinish the rabbets in the sash before bedding the glass. No matter how carefull I am with my seals and glazing, I know the realities of water finding its way into where it shouldn't.
What do I do? Give up on the linseed oil paint? Use an epoxy to seal the rabbets? Find some way of sealing the window seal with a foil tape, urethane caulking, or other barrier against the linseed oil? I dont want to be scraping or sanding to refinish the windows on a regular basis and would like to avoid the common film finishes because of our climate.
I use Awlgrip marine paint for.my higher exterior jobs. It's the best stuff I have ever used, but stinks to heaven.
Good practice will dictate (opinion) that there be a good seal between the wood and the glass at the exterior rabbet, no matter where or what. We use a pure silicone that will not react to the IGU seals, and will last well over 30 years. We double that up by also sealing in the interior loose wood stops, giving a uniform clean look to the glass. Use a color that fits in with the ash color, and apply so there is squeezeout all along the glass/wood joint. Let it set for 2 days before cleaning off excess. Urethane also works, but takes longer to set up.
Check with your glass vendor on what solutions they recommend.
The theory is that no water can get into the area between the glass and the wood, so no need to prefinish.
For an exterior finish I would look into Cetrol by Sikkens Co. All the painters, boat owners, and my customers I have talked to love this stuff. Goes on like oil but looks like
Thanks guys for the suggestions. Ill look into them. Cetol is not my preference as i had a bad expierence with them some time back where moisture from the back side of the wood caused the product to lift in less than a year. I was advised to only use the product in wet climates where the application allowed for all sides to be coated in their product.
Ill see what the glass manufacture suggests about compatible products.
Stephan - Here is a great thread with good info from knowledgeable people about insulated glass.