could you insulate whatever parts you don't want coated?
No, The parts are pressed together then the plunger is welded to the assembly. There is no way to isolate the polarity of one piece.
Or can you change the material the pin is made of so it won't take a charge? (ceramics?)
Gave that some thought too. The problem is that the pin needs to be rugged. It's a safety device that stops a "falling load" incase of failure. I fear ceramics would be too brittle. Also, it would require a months long design change approval/testing/BS process.
is plating pior to assembly an option?
Yes, we currently have them bright zinc plated before coating. The Zinc is a little tougher for the E-coat to bond to so it helps some.
jurgen: Various
You have some good ideas there on a coating. I do not believe we would be able to "isolate" the polarization, but a slippery non-stick coating may really help.
could you wrap it pre dipping...duct tape/tiny condom comes to mind.?How about applying a length of shrink tubing before ecoating and then remove it after?
Another good idea. The clearances are very small so you would have to be quite creative but is is definitely food for thought.
Teflon is a fairly standard coating used in automotive fasteners to keep the e-coat buildup off of threads.
That was my initial thought. There is however one problem. The other end of the pin gets pressed into a knob so the operator can activate the plunger. The end of the knob needs to accept the e-coat to maintain proper appearance. There may be a way around this though.
Wax?
The problem here is that the parts get a high heat solvent bath before coating (so their pool does not get contaminated with oils, etc..) otherwise it would be great!
Can you make the plunger out of plastic.?
No, for the same reasons stated above regarding ceramics.
You guys have some great ideas! I will post a pic too, thanks again!!!!!!!!!!!!!!
P.S. One of these days I'll figure out how to do bold and color changes etc.. so my reply posts will be easier to read
