Fill and fix expanding foam is a quick setting one part polyurethane foam in aerosol form the fill and fix version is supplied with attachable nozzles and gun grade is supplied for use with our range of applicator guns the foam expands on application to up to 50 times its original volume and expands on application by 150 once cured the foam can be cut sawn or plastered over after only an hour providing the working temperatures can and surfaces are between 43 5 to 43 25 c ideally 20 c benef