WPSC

Putty & Glazing Compound

Putty and Glazing Compound Types

Traditional Linseed Oil Type, Drying Vegetable oil
A putty made with whiting (calcium carbonate), and a drying vegetable oil such as linseed oil. It is formulated to a thin or thick putty that is easily handled and does not stick to a putty knife, called “knife grade”.

Modified Oil Type, Resilient Hardening
Often made with whiting or other minerals such as ground limestone, drying oils such as linseed oil or safflower oil, with mineral oil or other plasticizers added to enhance or extend flexibility during the service life. Metallic driers may be added to enhance quick skin over. It is formulated to a thin or thick putty that is easily handled and does not stick to a putty knife, called “knife grade”.

Acrylic Elastomeric Type, Flexible
Made with silicone-acrylic blend resins and water into a "gun grade" paste applied with a caulking gun and tooled with a flexible rubber tool. Dries within a few hours for painting with good adhesion and some volume shrinkage as it cures into a flexible rubber-like material after a few days.


Acrylic Type, Hardening
Made with water, acrylic resins and mineral fillers. Dries within a few hours for painting into a hard material with a slight resilience after a few days.

(Source: "Save America's Windows", by John Leeke, 2009-2013)





Generic Descriptions of Specific Products

Notes & Discussion:
The published standards will not name any specific products. Instead, generic terms and descriptions will be used. Here at the Forum we can name and talk about specific products in order to come up with generic descriptions of the products.

Please tell us about the putty or glazing compound you use, why you use it, and what it's performance is, both during glazing and length of service life, and how it fails. Do you think failures are due to the material itself, or to how it was applied, maintained, etc.?

_________________
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com

When using Glazol, it is important to open the can and soak up all the oil on the top with paper towels. Then remove all the putty from the can and pad off any additional oil from the mass of putty with paper towels. Dispose of the paper towels safely. Now put the putty into another container for mixing. Add 1/8 of a cup of boiled linseed oil to each gallon of putty. Mix the oil into the putty slowly with a paddle mixer and tranfer it back into the original can. This creates an affordable boiled linseed oil putty that is readily availbale at just about any paint, hardware or lumber store. This skins over in 24 hours for painting and 4 to 5 hours if direct air is blown over the tooled putty.

So, this is substituting boiled linseed oil for some of the oil in the Glazol. Very interesting.

Have you used this method with any other putty or glazing compound product? Or, is it specific to only Glazol?

Is the "paddle mixer" an electric power tool, or is this simply using a paddle by hand to mix the oil into the putty? How long does it take to incorporate the oil into a gallon of putty?

_________________
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com

I've been doing this for years. It's a paddle mixer (used to stir 5 gallon buckets of paint or drywall mud) in a heavy duty drill. Dap will not take the boiled linseed oil as well for some reason. Glazol is the only one I know that will. Mix for about 5 minutes. I used to have to do this regularly with Permaglaze before they went out of business. The boiled linseed oil would evaporate from my 5 gallon drum and I'd have to add some more and mix with a paddle. The Glazol mixing is the easiest, most accessable and cheapest way for the average workshop attendee to have boiled linseed oil putty. Sarco is a pain for anyone but the pros to deal with, great putty but no credit cards etc.

Remember, I've had zero failures with Glazol for over 20 years. 10 years ago it had boiled linseed oil in it.

This topic asked for what and why we use a certain putty vs another and whether we have had any problems so I thought I would throw in my two cents worth. Remember, you get what you pay for!

Our company used the UGL Glazol product on two different projects where we had a material failure. One project required that every sash be reglazed and the other was fortunately isolated to just a couple of sashes. There was no change in our standard procedures prior to glazing, curing, or painting that leads us to believe it was user error. I would best describe it as severe shrinkage cracking leading to the paint peeling off and the putty literally falling out of the glazing rabbet approximately 30-45 days after glazing.

We went so far as to have UGL send a representative to one of the project sites to determine what was causing the issue. Their response was inconclusive and they didn't offer a solution or replacement material. About $10,000 later we had reglazed all of the sashes with our new friend Sarco Multi-Glaze Type M.

Since switching we have had zero issues and are currently in the middle of glazing approximately 2,500 panes of glass at Historic Fort Leavenworth with Sarco.

I would agree that to a homeowner Sarco may not be as convenient as running to the local hardware store, but the slight hassle is well worth their superior product. The consistency, tool-ability, and paint-ability of their putty works great for us as a medium scale restoration company.

Corey, welcome to the Window Standards project, and thank you for your glazing knowledge.

_________________
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com

John,
I was glad to hear of other types of glazing compound I will definitely strive to track down a source of supply. I was taught to glaze thirty years ago by the Delsman brothers and all they ever used was DAP in a 25 gallon barrel. I work in a semi rural area with limited suppliers and have never used anything else. I have also had several restoration projects specifying "DAP33" or equal. I do add whiting for workability to some batches but I have had painters concerned about 'chalk release'.

Glazol is actually 80% ground limestone while Dap 33 is about the same percentage of calcium carbonate which is different than ground limestone. Dap for some reason also has parifin wax in it. So, I do not think they should be in the same category.

Corey, I'm sorry to hear you had failures with Glazol. I use it as described above and have so for over 20 years with no failures. Sarco M is great stuff as well.

Regardless, I think the point is that based on all the pros around the country we should somehow generically rate boiled linseed oil putties as the prefered putty.