How to fill handlebars with expandable foam

[Ebme Geek]

Standard silicone would take a long time to cure all the way through, and the ones that smell like vinegar release acetic acid that will corrode the bars from the inside, not a problem where a full cure is achieved quickly but here I would not recommend it, cure rates are often only a couple of mm's per day. Better would be a two part mix compound that cures after mixing