When it comes to restoring historic windows, what you choose to glaze your windows with can make or break your project. In this post, Melanie (from Glaze Craft Windows) and I outline the most reliable options we’ve used in the shop and on-site.  Hopefully, this will help you hit the ground running.

What Is Glazing Compound/Putty or “Glaze”?

Glazing compound (or window putty or “glaze”) is used to hold the glass in place and seal the sash against the elements. It’s a small detail, but it plays a big role in the longevity and performance of your restoration. The right compound makes for smooth tooling, has reliable adhesion, resists mildew, and holds paint well.

Sarco Glazing Putty

I’ve used Sarco products for years and keep coming back to them for their reliability and mildew resistance. Sarco makes two primary types of glazing compound:

1. Sarco Dual Glaze

• The only glaze I use for metal windows
• Good for glazing wood windows in place when they are exposed to the elements
• The negative with Dual Glaze, is it takes up to several weeks to fully skin over, which can slow restoration time down

2. Sarco Multi-Glaze Type M

• Designed for shop use — great for glazing wood sashes in the shop, where they are not exposed to the elements
• Smooth and easy to work with, skins over fairly quickly (in a few days) and is the glaze most commonly used for wood windows

Both options require curing period before painting, so factor that into your timeline.

Sarco Glazing Compound: https://www.sarcoputty.com/packages

Please see my full course to learn how to glaze like a pro.

Linseed Oil Glazing Putty

Melanie likes using Brauns & Co. linseed oil glaze for certain projects. It’s a traditional, all-natural option that:

• Can be painted immediately after tooling
• Offers a classic look and feel for historic restoration

Linseed-based putty takes a bit of experience to work with, but it’s a solid choice for purists or when you’re on a tighter timeline.

Brouns & Co. Linseed Oil Glazing Putty:

📦 In the US, available here: https://linseedoilpaint.com/product/fillers/linseed-oil-putty-filler/

📦 In the EU, available here: https://linseedpaint.com/product/fillers/linseed-oil-putty-filler/

Please see my full course to learn how to glaze like a pro.

Cleaning Up: Whiting, Pumice, and Drywall Compound

Once the glazing is tooled, there’s usually some oily residue on the glass. To clean it up, we recommend:

• Whiting powder (traditional and effective)
• Drywall compound (a budget-friendly alternative)
• Pumice powder (great for a clean finish on old glass)

Each one works well to absorb leftover oil and leaves the glass clean and ready for paint. 

See my full course on how to properly use the materials to clean the glass after glazing.

Pro Tip: Avoid Certain Glazes at all Costs

Skip the off-the-shelf glazing putty from big box hardware stores.  It’s trash. It’s poor quality, dries inconsistently, and doesn’t last. You’ll end up with cracked glazing or failed seals in a few seasons — not worth it.  It often mildews under the paint too, meaning your windows are going to quickly look rough.

Final Thoughts

Glazing isn’t just a step in the process — it’s the thing that holds your whole restoration together (literally). Using a high-quality glazing compound like Sarco or Brouns & Co.’s linseed oil glazing putty makes the job easier, lasts longer, and protects the historic character of your windows.

Meet Mitch and Melanie:

Mitch, creator of Low Budget Window Restoration, offers online courses that make restoring wood and steel windows simple and affordable for DIY enthusiasts. Learn more at lowbudgetwindowrestoration.com.

Melanie, owner of Glaze Craft Windows, specializes in restoring pre-1945 wood windows using eco-friendly methods and traditional craftsmanship in the Mid-Atlantic region (including the Northern Virginia and Washington DC area). Visit glazecraftwindows.com to explore her services.

Follow Us on Instagram

Mitch: @onlinewindowrestorationguide

Melanie: @glazecraftwindows

For more step-by-step guidance on restoring historic windows, including Melanie’s expert tips, check out my online courses at lowbudgetwindowrestoration.com. Come learn, preserve, and celebrate historic craftsmanship with us!