Historic HomeWorks Forum

[Bob Brown]

I read in the tips on using Sarco Dual glaze putty that they do not recommend priming after glazing, yet most advice I've read says to prime with good oil based primer.
Can anyone clarify this for me?
Thanks

[johnleeke]

I have always primed Sarco Multi-Glaze Type M and Sarco DualGlaze with an oil-based alkyd resin fast dry primer (California Fast Dry "Trouble Shooter" Primer, with California 2010 Acrylic waterborne topcoats) on thoroughly skinned over putty, and never had any problems.

Primers and paints are formulated to work together forming a paint coating system with a specified thickness and performance characteristics that give maximum durability. If a component of the system, such as the primer, is left out then durability may suffer. This is why I always use a primer, even on the putty. I'm now getting 15 to 20 year life on painting sash, including the putty, with this method.

I believe the good folks at Sarco recommended against primer because they have gotten many calls from people having problems using the wrong kind of primer and not letting the putty skin over enough. There are penetrating slow-dry primers that have types of solvents that are very slow to evaporate, and this can cause putty wrinkling and other problems with the putty. (These slow-dry primers ARE very effective and durable on wood.) The Sarco folks end up recommending against all primers because it is difficult for many people to recognize the difference between the types of primer and for many of them to develop methods and procedures that are effective, such as waiting long enough for effective skinning over.

If you follow the sash glazing and painting method and procedure in my book, Save America's Windows, you should be able to use the materials mentioned above with good results in most climates around the country.

It is always a good idea to test any methods and materials that are new to you on just one or two windows, before proceeding with extensive work. Some materials and methods may work fine in one climate and not in another, or for one workers and not another.

[Bob Brown]

This makes sense. Thanks for the explanation.