Putty

Putty

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Putty

Intumescent firestop putty being used over top of ceramic fibre packing to restore the two-hour fire-resistance rating of a concrete floor slab, with cable penetrants in a building in Vancouver, British Columbia, Canada.

Intumescent firestop putty used in a successful fire test, which led to a UL certification listing.

Putty is a generic term for a plastic material similar in texture to clay or dough typically used in domestic construction and repair as a sealant or filler. Painter's Putty is typically a linseed oil based product used for filling holes, minor cracks and defacements in wood only. Putties can also be made intumescent, in which case they are used for firestopping as well as for padding of electrical outlet boxes in fire-resistance rated drywall assemblies. In the latter case, hydrates in the putty produce an endothermic reaction to mitigate heat transfer to the unexposed side.

Overview

Specifically putty has been used extensively in glazing for fixing and sealing panes of glass into wooden frames (or sashes), although its use is decreasing with the prevalence of PVC and metal window frames which use synthetic sealants such as silicone.

Certain types of putty also have use in the field of terminal ballistics, where the putty can accurately represent the average density of the human body. As such it can be used, for instance, to test the penetrative power of projectiles, or the stopping power of body armour.

Glazing putty is traditionally made by mixing a base of whiting (finely ground chalk) with linseed oil in various proportions. There are a number of synthetic alternatives such as polybutene based putties, where the polybutene is a low molecular weight oligomer replacing the linseed oil. Butyl rubber is also added to the mixture to provide some strength and flexibility.

In woodworking, water-based putties are more commonly used, as these emit very little odour, are more easily cleaned up and are compatible with water-based and latex sealers.