Hi, I worked at an assembly plant in the paint dept's sealer section, I think what you are seeing is we would seal seams in the metal with a brush at the end of a wand, kind of like a pump up sprayer wand, some times after we would change a barrel of sealer you would run the gun some where to make sure the psi is correct and there is no air in the lines, you didn't want to do it on a seam because you may have air and cause a bad seal, under the hood they didn't say to much about the looks as long as you didn't put it in a spot that would be a problem with a fitment or over bolt holes. Roger
