I was going to put some used pistons in my Hemi rebuild, so I started doing some research on how to make them "new" again. Through this, I found a ton of stuff on coating the top's of the pistons with a thermal barrier and the sides with a dry lubricant. I think the 4 big guys in the coatings are:
HPC ---- http://www.hpcoatings.com/
Jet hot ----- http://www.jet-hot.com/
Swain Tech ----- http://www.swaintech.com/
Tech line Coatings ---- http://www.techlinecoatings.com/
It is interesting that all of these manufactures mention that the coatings they use, were spin offs from NASA and aerospace application developments.
I was curious if anyone has played around with these coatings...
In the case of Techline, they sell their product line to a large number of small powdercoating guys.
They do make the following points in one of their online FAQ's
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Surface Prep:
* Parts first must be sandblasted at low pressure (40 psi using a suction type blaster) using fine sand (120 grit aluminum oxide is recommended), NOT with glass bead. Then the part should be degreased using acetone, lacquer thinner, M.E.K. or similar non petroleum based solvent that leaves no residue. The coatings should be applied with an airbrush or detail touchup gun. Baking may be accomplished with any oven. Kitchen ovens or even toaster ovens work just fine. Obviously the size of the oven will determine how large a part can be coated and cured.
# DOES IT MATTER HOW THICK I PUT THE COATINGS ON?
* YES, the coatings are thickness sensitive. Generally .0015" is the maximum thickness recommended. This thickness will be achieved when a solid color is seen. Putting any coating on too thick can cause the coating to crack, flake or bubble up.
# CAN I USE GLASS BEAD TO CLEAN MY PARTS?
* No: only use fine sand or fine aluminum oxide. Glass bead is round and while it is a good cleaner it closes the pores of the metal. Use fine sand/aluminum oxide which etches the metal and cleans/opens the pores allowing the coatings to bond into the metal.
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Some of these coatings require baking at temps in the 450 - 500 degree range which can modify hardness even on steel components so I can easily see where the same might apply to aluminum pistons.
Techline gives lots of technical info on their site for their specific coatings. Since they sell through vendors they also have application guidelines, and some news letter items, that as seen above, lead me to think the application process and surface prep are as important to the success of the coating as the brand/type of coating.
I suspect that many of the problems with chipping flaking coatings would turn out to be traceable to over thick application or lack of or improper surface prep and curing.
I have limited experience with the coatings having only used some of the techline products in a do it yourself application. But they seemed to work okay for my application ( exhaust system coated with their black satin ).
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