Friday, January 25, 2008

Windows - Getting the Glass Back In

When last we left my windows, they had been stripped of many layers of old paint and the glass had been carefully removed and set aside. I had treated the bare wood with BoraCare, a borate wood preservative, for good measure. Now I was ready to put the whole thing back together.

At this point, I carefully inspect the little inset bed where the glass once laid. Every minuscule bump, every piece of old putty, every little sliver of wood, every broken piece of a glaziers point (the little metal tabs that hold the glass in place) needs to be removed and the bed needs to be sanded smooth. An old dental pick helps here. Tedious work, but it will save untold anguish later. Turns out old glass is very fragile and when laid in an uneven bed, can crack.

Next comes a coat of primer. I use Zinsser's oil-based Cover Stain. It's an interior/exterior primer that sticks to just about anything and dries quickly. I prime both faces (inside & outside) of the sash, the bed where the glass will rest, and the top and bottom edges. I don't prime the left & right sides of the sash. I let the primer dry for a day or so.

Now I veer off from normal instructions you find online. I paint the interior face of the sash. I've been using Benjamin Moore's oil-based Super Spec in a semi-gloss. I use two coats. I'm careful not to get any paint in the glass bed or the exterior side of the sash. I finished one sash before I figured this out. By painting the interior face, you later save yourself the hassle of trying not to get paint in the installed glass. It gives you a nice crisp edge on the interior. I let the oil-based paint dry for a few days. In the meantime, I work on restoring the paint laden hardware. I also clean the glass. I use a razor blade to remove old paint and oven cleaner if the glass has a serious film on it.

Once the paint is dry, I flip the sash over and get ready to reinstall the old glass. Once again, here I veer off from normal instructions. Most people put a small bead of glazing putty in the glass bed. You need something soft there for the glass to rest on. You also want something that will hold the glass in place and weatherproof that spot.

When I first started working on my windows, I found company that made small tubes of silicone to use for this purpose. Of course, once I used up my first tube the product had been discontinued. However DAP makes a silicone product that is very similar, so I have been using that. I squeeze a very thin bead of silicone in the glass bed...then oh-so-carefully place the glass on top of the bead of silicone. Remember, you only want the silicone in the bed underneath the glass - you don't want it on any of the sash face wood. I make a dry run with the glass before putting down the silicone - because pulling glass up from silicone because it doesn't fit will give you an instant migraine.

The pros/cons of using glazing putty to bed the glass: It is easy to use & clean up. If the glass breaks anytime in the future, it will be fairly easy to remove. However, it is not especially weatherproof and will deteriorate in water & snow.

The pros/cons of using silicone: It's easy to apply. It's clear so, it doesn't show through the glass. It is water & wind proof and won't deteriorate. However, it really holds that glass in place...and if the glass ever breaks removing the silicone to replace the glass will be a lot of work (as anyone who has recaulked a tub knows). It also will not hold paint, so if you accidentally get it on a surface that will be will need to be removed.

Once the glass is in, I put very light pressure on the glass to make sure it beds in the silicone. Then I put in the glazier's points. There are a few different varieties. I personally like the ones that have a little ridge that allows you to use a putty knife to slide them into place. I usually space them about 6" apart. Once again, I set the sash aside to dry (are you getting an idea of why this takes me so long?).

When the silicone is dry, I start to apply the glazing putty. I'm going to stop right here and say - if you are going to reputty your windows go out immediately and buy a glazier's tool. They sell for a little over $5 at most hardware stores. One of the old timers at my neighborhood hardware store took pity and me and showed me the trick to using them. After that, puttying became a joy.

I use DAP 33 glazing putty (buy the kind in the metal can, if you can. The plastic tub dries out easily). I tried other stuff, including the type that comes in a caulk style tube - bleuck. One thing I found helpful is to take a big clump of putty out of the container & knead it. I think the oil tends to separate and kneading it helps the consistency so it tools better.

I roll a thin rope of putty and start working it into the bed over the glass. I use the V end of the glazier's tool to run down the putty - keeping on edge on the wood and the other floating over the glass. It takes a little practice, but this will form and near perfect angle. Every now & again I take a look at the putty from the underside of the sash. You don't want the putty to show past the wood on the interior side of the sash. This is my favorite part of restoring the windows. I find working the putty relaxing.

Once the putty is in guessed it. It needs to dry. I generally wait a week or so for is to develop a "skin" on it. Essentially it won't feel sticky when you lightly touch it. It will stay soft. The new putty doesn't harden like the old stuff.

Once the putty is ready, I prime the putty with my oil-based primer. When the primer is dry, I paint the exterior of the sash & putty with Benjamin Moore MoorGlo SoftGloss acrylic exterior paint. I do not paint the side edges of the sash - paint makes it difficult for them to slide up and down in the sash channel. When painting I want the paint to run ever-so-slightly on to the glass to form a seal around the putty. I use a nice angled sash brush to paint this part. When the paint is dry, I clean up any boo-boos on the glass with a razor blade.

When the paint is dry, I reinstall the old hardware - now all clean & shiny.

Next, putting the sash back in the window.......


Sandy said...

Whew! Made me tired just reading about all that work! The windows are going to be super when you get them finished!!

Jen said...

I am tired too... and I have 31 of these to work on ...I am waiting until summer. Eugh....

Jennifer said...

Wow... such a good primer to go through... your series is prepping me for a possible start this summer!

Anonymous said...

Wow now that is crazy...I mean amazing! Ditto on the primer comment. I've read "Working Windows" but am usually too timid to just tear into a project like this. This is great info - Thanks!

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