2. At first, we thought these $50 tubes of seam sealer were unnecessary. Dustin, on the other hand, knew better. Seam sealer is a product used by all professional body shops. It fills in the space between body seams, giving a more uniform and consistent appearance. After applying the stuff, Dustin smoothed it off with his index finger. Seam sealer uses two separate chemical parts, similar to an epoxy, and a special mixing gun to combine and apply the gluelike substance. Once applied, it only took about 15 minutes for each seam to cure rock-hard.