After the coated parts have finished curing, Jet-Hot uses a vibratory polisher that not on
But Burton adds that sometimes a single coating can't cover every situation. Instead, Jet-Hot applies two different formulations in order to provide maximum protection. "At high temps you are getting thermal oxidation," he says, "where at lower temps you mainly need protection from chemical corrosion from salt, moisture, and things like that. The higher temperature coatings are more porous because they are more ceramic in nature and with the combustion spraying process the mixture isn't in a liquid slurry state before it is applied.
"So what we do with our high-temp applications is give that component a second coat. After applying the high temperature coating, we give it a top coat that's more impervious to moisture and chemicals. And we're also one of the only ones I know of that coat all the headers we do both inside and out. That process gives the headers the best protection possible."
Incidentally, Burton says Jet-Hot is able to coat used headers as well as new. Many assume that used headers can't be coated because the grain of the metal has been contaminated with oil, dirt, and rust. It's true that these types of contaminants can keep a coating from properly adhering to a set of headers, but Burton says that when the proper procedures are used to make sure these contaminants are removed from a set of used headers, the results can be just as good as what you normally see on virgin steel.
"No matter whether we are talking new or used," Burton says, "the process of preparing the headers before they are coated is critical. When the part comes in, the first thing we do is scribe an I.D. number on it on the flange or somewhere else where it won't be seen or cause a problem. That number goes into our system so that we can track the part into the future.
"After that we will clean the part, and then it will go into masking if there are any requirements there. The next step is blasting where we are getting rid of any oxides, residues, old paint, and basically just everything until we get down to clean, white metal. Then we clean the part again before we start the coating operation.
"And like I said, the headers don't have to be new. For the case of used headers we go through a little more work to clean them up, but no used parts have to come in here already blasted. We do everything here, and we basically have to in order to make sure the process doesn't go sideways. So you don't have to do it yourself because we're going to do it again anyway.
Headers must be protected from both thermal and chemical corrosion. Jet-Hot uses a base co
"Say, for example, someone has already shot blasted a set of used headers. They may look really good, but if they used steel shot, that's imparted small amounts of iron into the surface that will then rust. And that will cause delamination of the coating down the road. Or if there are still oil contaminants left on the headers, that can cause problems because we are working with water-borne coatings. As you can expect, the oil contaminants are going to separate from the mix and cause problems there as well. So if you have a pair of used headers, that's no problem. You can clean them up so that the dirt isn't falling off of them, but don't go to too much trouble because we're going to put them through the full process regardless. It's the only way that we are able to guarantee our customers are getting a top quality coating."
Check for Quality
One problem that many racers have is it can often be difficult to gauge the quality of a coating until it's too late. Obvious problems, like thin spots or immediate cracking are easy enough to spot. But more often, poor quality coatings may look good at first but then start flaking off or delaminating later on after the headers have been on the race car and been put through several heat cycles in races.
One of the final steps is hand polishing, which also allows every part to be visually insp
Burton suggests an easy test most racers can do themselves in addition to a thorough visual inspection. Use an ohm meter to check how conductive the coating is by placing your probes in two easily accessible areas approximately 12 inches apart. This reading is your baseline, because the coating is usually best in easy-to-reach areas of the part. Now place one of your probes in a seam, weld, or a more difficult to reach area of the part. The reading should be approximately the same. If it isn't, it's probably because the coating wasn't applied consistently across the part.
Now you can be sure your parts are coated well and go out and race with confidence.