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Q.The label on my bottle of Rhino Ultra Glue states (in capital letters) "Keep from freezing," but doesn't say what to do if you don't. Can polyurethane glues be thawed and reused? When they freeze and then thaw, is it obvious that they've been affected? Even though these glues are pretty expensive, I'm wondering if my small $13 bottle needs to be thrown out because I accidentally left it in the truck overnight.

A.Mark Stypczynski, manager of technical development at Macco Adhesives/ICI Paints in Strongsville, Ohio, responds: Rhino Ultra Glue (800/634-0015, is freeze/thaw-stable. While it will thicken at low temperatures, it won't separate or otherwise be adversely affected, and it'll return to its normal viscosity upon warming.

Still, adhesives shouldn't be stored in a freezing environment. Because these products' viscosities are considerably higher when they're cold, it's possible that an inadequately warmed-up adhesive won't completely wet one (or both) of the bonding surfaces, which could result in a failure at some point in the life of the assembly.

In addition, cold adhesives — whether latex, rubber-based, or reactive (such as polyurethane) — take longer to dry or cure, increasing the possibility that panels or parts will shift before the adhesive has hardened; that too can result in failure.

Finally, while most manufacturers test for freeze/thaw stability (typically for five cycles), repeated freezing and thawing can ultimately cause irreparable damage to some types of adhesives, especially latexes, making them unfit for use.