Talk About Static Cling...

Which cartridge is used probably shouldn't make any difference, as the cart connection is always grounded if your ground lead from the TT is properly terminated. As for why conductive objects around the area may provoke no static discharge when touched, this is because of your relative lack of motion before touching them (in this type of case, it's not the object, but the person which is exhibiting static charge - the metal object being the ground drain). Just like rubbing a balloon on your shirt, scuffing your shoes accross the carpet, clothes tumbling in a dryer, or driving your car's tires down the road can all produce static build-up, it requires energy input in the form of relative motion to separate the charged ions in the air between + & - on the respective nonconductive surfaces, creating the voltage potential that attacts dust,or is released in a spark or a shock when grounded by a person's touching a conductive surface like a car door handle. I frankly am not sure if the static build-up on a record is solely due to the friction of the needle in the groove as it spins, or if the record's motion through the air alone is enough (in the car example, they say it's the road friction, but I wonder whether moving through the air is also a part of it, since I do believe that airplanes can develop a wicked static build-up in flight - but they also have rubber tires that come into play on take-off and landing, so who knows?). You may want to experiment by "playing" a record without the needle being in the groove for 20 minutes and checking the result. It's also possible there may be some difference in the severity of the problem stemming from the use of a dust-cover, if one is present, so try removing it as well if this applies. But a little added humidity (just a little, not enough to cause condensation), as TWL suggests, will always help and probably couldn't hurt if employed conservatively. You might simply try placing a bowl of steaming water in the listening space to produce some humidity silently. Good luck!

It could be the slippage of the record against the mat. Record clamp makers claim that the record travels less rotational distance than the platter/mat does during playback, because the record slips slightly if not firmly coupled to the rotating platter. With a felt mat, especially, this sort of friction might be a considerable source of static electricity buildup. Does a sorbo-gel mat provide better traction for the disc? I've never used or touched one, so I don't know. I know they are primarily sold for absorbtion dampening characteristics, but maybe they provide better traction at the same time.

Have any of you with record clamps or sorbo-gel mats experienced less static as a result of using these tweaks?

this is getting interesting: I've considered the insulating properties of my extremely thin "analog survival kit" mat & agree that is probably aggravating the situation. I do want to try spinning the platter for ~20 min. without the stylus engaged simply to determine the mechanism involved here. Also want to try out playback once without the mat in place (record then contacting the metal platter directly) but I do like to use the mat because it improves the sound. A conductive mat would be interesting - possibly carbon impregnated for conductivity? I'll try to research some alternatives. This is the VPI Aries platter & bearing on an HW19MK4 table. Thick & springy mats are not recommended for this rig.
Dust cover is always in the raised-hinge position during playback, but removing it altogether could be someting to try anyway.
There could be some negilgible platter-to-record slippage but I do use the 2-piece VPI delrin clamp which holds very tightly. VPI suggests applying talcum powder to the belt, so I might as well try that too. Interesting idea trying to measure the static potential (I'll use my scope which has 10 M-ohm input impedance) that should tell whether the charge is building up on the record as I highly suspect, or the platter.
Household humidity is normally 55% to 60% which should be plenty good enough.
Lots of good interaction & ideas here - sorry Mot for jumping in; I'm really not intending to hijack your thread.

Not a problem, Bob. A solution for one may be a solution of all. On my Nottigham, I am using the foam pad that is supplied. Funny because Nottingham as recessed the label area and beveled the edge of thier platters for reasons discussed in some detail elsewhere. Then they go and give one a foam mat which seems to defeat the purpose of the bevelling and the recessed "center". I have used the platter both with and without the mat and find no great difference, though it does sound a bit more detailed WITH the mat. Go figure. Anyway, with or without the mat does not effect my static problem.

I had my wife queue up an LP then stood still in front of the TT on a rubber mat while the side played. Upon completion, I had her mute the pre via the remote. I reached straight out and "unqueued" the LP. Same static. This would seem to negate the presence of static generated by my movements around the room. Will also try to the "non stylus engaged" mode. I will also go on to say that this does seem to be much worse with certain LP's, as Lugnut mentioned, so it must be a combination of factors.

Static electricity is quite amazing. You either need to prevent it from building up, or find a way to bleed it off. Almost any insulated object traveling through the air will build up a static charge. What material it's made out of will help determine how much charge it will hold. In the lift truck example, operators were being "shocked" when they reached to pick items from metal bins. I had to install a copper wand bonded to the lift truck. They had to touch the bin with the wand to discharge the static. The water flowing through the pvc pipe supplied a water trough for livestock. The animals stopped drinking from the metal trough. I had to actually bond the pvc every 10 ft and drive a ground rod to bleed the static charge off from the water flow through the pvc. We make sure that we bond ourselves with a wrist strap when using double insulated tools around static sensitive equipment. The spinning cutting tools can cause a very large charge to build up. You really don't realize just how well insulated your body is. So I would suspect that an LP spinning in the air, just might build up a static charge. Maybe someone could build a system to blow humidified air on the LP? Just an idle thought......Bob D