Hi everybody I asked this question before and have not made a decision. I am installing some Mahogany windows that are double glazed and have all sorts of hi-tech coatings on the glass and for the interior finish I am thinking of either a marine grade spar varnish or shellac. I like the idea of shellac because of the ease of application but am worried about people cleaning the windows with Windex or other window cleaners with ammonia is this a real concern?
Thanks
Troy
Replies
I think the cleaner problem could be real. As much as I like shellac, I wouldn't choose it for this application.
With double pane, low-e coated windows, UV light would be significantly reduced. You would get a somewhat harder finish if you used something like Behlen Rockhard. Or Waterlox Gloss which is a phenolic tung varnish and has some natural UV resistance of it's own. But generally, I the marine spar would stilll have the most longevity, as long as you didn't expect a lot of wear.
Thanks for the feedback. There are a lot of opinions about shellac for this use. I know the spar varnish will work it just smells more and dries slower.Have a good weekend.Troy
I shellaced and waxed mine recently (pics in the gallery if you are interested). I love the look, but I know I will probably pay for it down the road. Washcoat, gel stain, shellac and then wax. I would listen to steve.
Brad
Thanks I'll take a look at your post.Troy
Look at the life expectancy of the window. Insulated glass and plastic balance systems last about 20 years, then it's time to replace the entire window. If you don't put a good seal on the wood, inside and out, the wood will expand and contract more, and the bond between the wood and glass will fail sooner. When that bond goes, water will get in, and cause the seals to go on the insulated glass. Look at similar windows made 10 and 20 years ago to see what your finish options will look like in the future.
Harold
Harold,
You seem to imply that there is a "bond" between a window's wood sash and the glazing that can fail, leading to condensation getting between the panes of glass in a double-pane window. That's not exactly correct - unless I'm misunderstanding your post.
Each glazed unit is sealed around its edges with a sealant. It is this sealant that, once compromised, will allow outside air into the space between panes. Thermopane windows are built with dessicant material in the spacers that separate the panes. These spacers absorb whatever water vapor is captured in the space during assembly. But if a seal breaks, the dissicant cannot absorb enough of the new moisture to keep condensation from forming, and that's when the window goes bad.
What interface there is between the wood sash and glazing has no effect on the seal - well, unless the window warps so badly that it twists or otherwise distorts the seal enough to break it. But that would be a very rare occurance.
Incidently, one company has come out with a method of "rescuing" double-pane windows that have a failed seal. Their claim is that they can restore the window for about a third to a half of what it would cost to replace it. They drill into the glass in two places, inject a cleaning solution that rids the glass of anything that might have been growing there, and then install one-way valves in the holes. It might be worth investigating if one had a lot of - or large - double-pane windows with failed seals.
Zolton
If you see a possum running around in here, kill it. It's not a pet. - Jackie Moon
Hi Zolton,
I was being brief, and skipping steps in the aging process of insulated glass windows. I understand what you mean about the insulated glass units being sealed, apart from the seal between the sash and the insulated glass unit. Insulated glass windows last only as long as the caulking that seals them. Eventually, the caulking fails, and water gets into the insulated glass unit. Anything you can do to extend the life of that caulking delays the day when the seal fails. Allowing water into the space between the sash and the glass tends to degrade the caulking. I don't know why the caulking is degraded, but I have been working with insulated glass windows for 23 years, and I have seen the damage. Can you post the name of the repair company? Being able to repair and re-seal insulated glass windows would save a lot of energy used and carbon produced by replacing glass and sash.Thank you
Harold
Harold,
Here's a link to a company that repairs double pane insulated glazing units. I'm a bit leery of this, but they say it works...
Zolton
If you see a possum running around in here, kill it. It's not a pet. - Jackie Moon
Thanks, Zolton.
The link didn't show up on my computer. Could you post the company name?
Thanks.
Harold
Harold,
That's odd. I did post the link. It's http://www.ccwwi.com/. Maybe something in the software stripped it out. If it does it again, the company's name is Crystal Clear Window Works Incorporated, and you can get to it by typing the first letters of each of those words into your brower's search window.
RickL said he posted a link the other day in a thread on slot mortisers, and it, too, never showed up. So maybe that's something this website is doing, possibly for security purposes - or maybe to confine links to paying customers..
Zolton If you see a possum running around in here, kill it. It's not a pet. - Jackie Moon
Hey Zolton sorry to jump in. Thanks for posting this site on the window re-sealing, I sell real-estate and I see a lot of 20 year old houses with this problem on the double pane windows and this might help some of my clients. Again thanksTroy
Thank you, Zolton. I got it.
Harold
Well since these sobs cost a lot I hope they last longer than 20 years but I will keep what you said under consideration.Thanks
I'm not sure what you mean by "marine spar varnish" but have you considered Marine Polyureathane Varnish. Get a thin one (some are very thick and slow drying) and apply at least 3 coats (first one thinned). As long as you finish the edges well so that water cannot creep underneath you should get 5 years before re-varnishing.
I suggest you do not use 2 part varnish. It is very hard but so impervious that any water which gets in will lift it.
My favourite marine varnish is Rylard's. I don't know whether it is available in the states. When my boat was laid up inside for 3 years the varnish remained as new.
I guess I should of been more clear(pardon the pun) about what I am going to do the outside of the windows will be painted and the inside will be given a clear coat. I keep going back and forth between a spar varnish like Epifanes or shellac because it is so easy to re-finish. My biggest concern with the shellac is that somebody might be over zealous with the Windex.Troy
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