Historic HomeWorks Forum

[johnleeke]

Traditional glazing putty has been carefully developed over the past four centuries to be easy to apply, keep a good seal between wood and glass for many years, and then fail gracefully. The way it fails is an important part of it. It fails so that it is easy to remove and replace with more putty.

People who are struggling (or spending a lot of work, time and money) to get the old putty out don't realize that it is often possible to leave it in place and do simple putty maintenance and spot repairs.

Remove any chunks of loose putty, but don't go crazy trying to get all the putty out. (If more than 15% to 20% is coming out I consider if it will be worth removing all the putty. It's usually a trade off between a limited budget now with a shorter life span of say 5 or 8 years, or spending quite a bit more now for complete deglazing and a much longer life span of 3 or 4 decades) Use a 1/2" wide steel brush and pull-type scraper to to clean up glass and wood surfaces in the glazing rabbet. The surfaces must be perfectly clean: bare bright wood, and sparkling glass. Maybe you'll need to use a razor blade on the glass.

When using this method it can be difficult to clean putty and oil off the neighboring glass and wood surfaces, so apply 2" wide blue masking tape to the glass along the edge of the putty before starting. Also apply tape to the face of the stiles and rails if you will not be repainting it.

Brush an oil-based primer on any exposed bare wood in the glazing rabbet and let it dry.

If the putty has cracks but is still well attached, brush some boiled linseed oil onto the line of putty and brush it back and forth so it soaks into the cracks.

If the putty surface is rough and needs to be smoothed, now is the time to sand it. You can use ordinary sandpaper; yep, sand right in the oil. The oil will help control any lead-containing dust. But, DON'T SCRATCH THE GLASS WITH THE SANDPAPER! If you do you'll be sorry, so DON'T. I use a thin metal slat from an old Venetian blind to protect the glass. If you can't get a Venetian slat then don't sand. (DON'T, if you do I'll just have to send you straight to your room with no dinner, then tomorrow and for the rest of your natural born days you will be looking through scratched glass and regretting it. (If you don't believe me, just ask your mommy.))

The oil will seep into the cracks, then brush again, more will seep in, come back in 10 minutes to apply a little more and brush, repeat for half an hour.

On a flat board, mix a little linseed oil into a bit of glazing putty so it forms a loose runny paste. Work the paste into the cracks with a tooth brush. Then work in some paste that is a little thicker. Fill any cracks that remain open with straight putty, working it in with a putty knife. Finally, wipe off all remaining oil and putty with a rag, refill any cracks still open. To clean up remove the tape and clean off the surrounding wood and glass surfaces with a rag and a little mineral spirits. (It's really better not to get any on the glass in the first place.)

Use the Place, Pack, and Tool method to fill putty into the sections of missing putty.

Let the putty dry and skin over for at least a few days then prime and paint as usual.

If you have to get this method done more quickly, use a penetrating drying oil such as Penetrol instead of boiled linseed oil. You can use the Penetrol on the bare wood instead of oil-based primer. This may shorten the life of the repair somewhat, so use boiled linseed oil for best work.

[muntinman]

What a fine and concise description. I tried to e-mail an architect friend instructions on this process and it was about three pages. The first time through was when I learned what can happen when your server connection expires;(

The one thing I would alter , for production purposes is the "place and pack" method. A homeowner doing a repair may not want to commit the time to learning how to "extrude and sweep" putty into the rabbet but a pro should be aware of it. One motion applies, packs and smoothes the putty. If we want to be affordable, we have to be productive, as long as the end product is adequately thought out and executed to meet the technical standards.

[johnleeke]

Point taken about the Place, Pack & Tool method. It is useful for training beginners to help them understand exactly how putty works. It was developed to serve the purpose of solving a few difficult putty problems for professional window specialists. Many pros condense putty placement into a technique with just one or two steps, which is fine. Technique is always up to the individual worker, as long as the result meets the standard. (Although I would insist that anyone still making putty snakes in a professional setting try another technique on at least ten windows. Well, even snakes can be OK; who would say having some fun making snakes is strictly forbidden? Not me. But, it can also be fun, after glazing a stack of sash, to lean over, stretch my back, glance at the clock and realize that I've shaved a full minute off my best sash glazing time record. Well...ALMOST fun.

It would be nice to see your full description of putty maintenance. Also, if you get the chance, could you show us the 'extrude and sweep' method of putty placement with photos or video?

[Luma]

I am a first timer trying to restore my windows and am struggling with removing old putty. My windows are original to the house and have been neglected for the last 20+ yrs. Considering this, they are in decent shape. I considered replacements (pressured into it) but couldnt see throwing out perfectly good wood windows to fill my home with vinyl. Thank goodness I found your forum. It has inspired me and helped me get started on my restoration.

The windows have a great deal of loose putty which came off on its own. I have been able to remove more of it using a steam box (thanks to your forum). However there still remain whole strips of stubborn putty on a couple of sides of the individual muntins.
You stated;

Remove any chunks of loose putty, but don't go crazy trying to get all the putty out. (If more than 15% to 20% is coming out I consider if it will be worth removing all the putty.

Do you mean 15% - 20 % of putty on the whole window, or on the individual rabbet? I am working on 12/12 sashes in my home so there are many strips of putty to deal with. If I can avoid removing all the putty I will gladly take that route.
I will need some advice on how to remove the rest of the stubborn putty if it is necessary to remove it all.

Once I am able to move past the putty and all the paint is stripped and wood is nice and clean I am not sure of the next step. I appreciate your guidance with this.

btw Catherine Brooks (Speedheater) recommended your forum and I have learned a great deal from reading about how to restore old windows. I am grateful for the valuable information I have gained from your forum.
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[johnleeke]

[Mark Nelson]

This information is great. Regarding the removal of old putty, I have worked with many different methods. Specifically regarding the use of chemicals, I have tried several. However, none seem to work quickly or work well enough for me to consider it a leading method. Might you have a recommendation?

Mark

[johnleeke]

Mark, welcome to the Forum!

Here is the main discussion deglazing and removing putty:
http://historichomeworks.com/forum/viewtopic.php?t=1587

By the way, you might consider posting more details of your chemical putty removal experience, methods, materials, techniques, etc.

I do occasionally use chemical, but other methods usually work better.