quote:
Originally posted by BigAl:
....I am not a "Filter Guy" but I do work in plastics. My guess is that the end caps are made of a fiber impregnated with an uncured thermoset resin, perhaps a phenolic. The media, center tube, and end caps are stacked up and held together and the whole thing is hit with RF (radio frequency-microwave radiation)tuned to a frequency which selectively heats only the end caps. This first softens them, allowing them to stick to the other parts, then cures them hard forever (thermoset.) The RF heating would explain why a metal center tube would not work.
You could be right on the curing and thermoset. In that case, you could not melt it with a soldering iron. I have examined the cartridge filter element out of my Ecotec. It appears to me that the filter media was dipped in glue and then set on the end cap. There is a layer of what seems to be a hard plastic with about 1/8'' of media next to it which is solid and dark like it was saturated with glue and allowed to cure. They have the same nylon center tube. I suspect the nylon is more about cost and reduced use of steel. It also eliminates any possible metal shavings from perforating the metal tube.
Well, FG? Am I close?
