Well..it really does set you on fire a lot and the only time i use it is in t2 Jelly. I wear bomber suits so is it worth getting fire resist pendants as well as volcanic helm? Or is volcanic enough resist to reduce the fire damage( as it does do a lot of damage at the moment
At RJP i wear:
Heavy demo (soon volcanic)
Ash tail (because my mad bomber suit hurts me >.<)
Volcanic Plate shield
Weps:
Electron vortex
Ascended Cal
Fang of Vog
I use Volcanic Demo Helm with Vog Cub Coat in RJP and the FoV self-fire doesn't bother me at all. Be sure to carry remedy pills in case you are low on health and catch fire. You can get a general idea of how much damage you'll take from the early FoV tests:
http://forums.spiralknights.com/en/node/10522#comment-95704
I'd prefer CTR trinkets to Fire Resistance trinkets, just so I can spam it more. It would help a lot if both your armor and helm resisted fire.
When I wear full Vog + 1x 5* Fire trinket I still find the amount of hp I lose to fire & frequency of self-lighting annoying. Solo or with a strong group this would be fine for Jk. As far as I'm concerned RJP can be cleared quickly with only an Acheron including silly fast boss fight (especially if you run CTR & DMG Max).
Oh also of note, unless a recent update has changed it, FoV + Damage Bonus also = higher self-damage.
I don't use my FoV a lot, so my opinion may not be the most valuable, but: The reason I don't use it a lot is that the fire kills me. I consider this weapon to be not worth the trouble, even if I'm wearing double Vog Cub. For me to use it, I would want double fire armor with additional fire UVs.
Edit: I guess that fire trinkets would help, but offensive trinkets seem a better use of trinket slots. Also, you really want a lot of CTR on that FoV, or else it's still not of much value. (The regular attacks are not impressive.)