Cut the rubber crumbs into small pieces if it has not already been cut. In most cases it will come cut and will require no further cutting. If the rubber crumbs are large pieces, use the utility knife to cut them it into small pieces about the size of a penny.
Pour the adhesive and rubber crumbs into the bucket. Make sure you buy adhesive for rubber crumbs, and not a random construction adhesive.
Mix the adhesive and rubber crumb mixture in the bucket with the electric drill and the mixing paddle for at least three minutes.
Scrape the sides and the bottom of the bucket with the spatula to mix any pieces of rubber stuck on the sides of the bucket.
Mix again the mixture with the drill and the paddle for about one minute. You can now use the adhesive and rubber crumb mixture.