Cheap well rated caps

[Stevem]

If you ever wonder why some caps perform better , last longer and can handle over voltage conditions better then others, then here’s why.

This filter cap was said to be made with plastic insulation, yet when it blew up long before its time you can see that the insulation is paper.

[imjonwain]

Not to be argumentative, I totally agree there is a major quality differences between different electrolytic capacitors and their constructions. But as far as I understand almost all electrolytic capacitors (I don't think SMD solid polymer electrolytics do) contain a "paper" that is impregnated with electrolyte sandwiched between the anode and cathode foils. Maybe they were saying the cap has plastic insulation on the outside?

[wpaulvogel]

Electrolytic capacitors have some sort of absorbent material inside them for the electrolyte. I can’t tell you what happened to that capacitor but I’ve only seen them open up like that when they are connected reverse polarity. Old caps can explode but new ones generally only do that from hooking them up backwards.

[pompeiisneaks]

I've seen one pop open due to being over voltage as well. On my tweedle dee, I had 450v rated caps and the first reservoir cap hit a little over 500 before tubes conducted, so it went poof

~Phil