I was asking earlier about fan filters but I can't find that thread. Any way, Electrical tape wasn't strong enough to hold the filters to the side of my case (I have 80mm fans and 120mm filters, because that's what was cheapest so they need to be taped). I had them duct taped on their the other day actually, but my drivers crashed my computer and I got a BSOD, so I kind of freaked out and ripped them off. I'm just wondering if the tape could hold enough of a static charge that it could possible damage something, before I take the time to tape them back on.
Well I heard that REAL duct tapes are electrically conductive because they have silver in it. Where exactly is the filter taped to? May be helpful with a picture. I might be wrong about the conductive thing since it is something I heard, I looked online and there is no constant answer.
For taping to the side of your case, duct tape is just fine. You'll want to make sure it doesn't start peeling, replace it if it does but I wouldn't be at all concerned about using it (I did for a while in fact - to hold a dust filter).
Well I do remember answering your thread you mentioned, anyways I hold my one of my filters with crazy glued rubber bands, thing is held really good. Though my rubber band is attached to the plastic part of my fan and it has been running fine for over 4 months. There are better alternatives to crazy glue but they were cheap cooler master fans.
Now that you mention it, my dad gave me that roll of electrical tape, which means he probably stole it from work, which means it's probably the cheapest stuff you can possibly buy. I got it duct taped on there right now though.