I can't seem to find exactly how spell damage works in the book...does anyone have a page number?
the question I have...Is it damage + stress die (eg: pillum of fire: +15 dmg and stress roll).
or is it damage + penetration, like with melee combat (eg: my pillum of fire exceeds the MR by 9 so dmg=15+9)
-Ag
Whenever there is no attack roll, the damage is simply added to a stress die (and in those cases the same goes for soak). This would apply to spells like pillum of fire.
Some rare spells might allow for attack rolls (example: a spell that makes a sword attack on it's own). Such spells would follow the usual attack roll system.
Page 116 of ArM5, middle of the right-hand column is a section labeled "Spell Damage." The heading is small so it's easy to overlook.
Further Question:
With normal combat, your decreasing ability to block the damage coming in raises the amount of damage you take....
With spell damage there isn't any...penalty for being injured...as far as I can see....
So basically you can take 50,000 light wounds and not die....
Is this correct????
Sounds about right. Most spells are auto-hit anyway, so your ability to dodge/block wouldn't matter. And a BoAF will kill you dead in most cases. 
umm...what?
We ran into this in our last game...
peck, peck, peck, peck...
Two magi 'crawling' around unable to kill each other...
...kind of ridiculous...
AND as things got worse they were increasingly unable to even hurt each other due to the penalties imposed.
I don't really see why. Assuming the spell penetrates in the first place, the Form Bonus to soak isn't that big. Sure, later spell may have trouble penetrating at all, but +30 damage is nothing to sneer at.
Sure but when one Magi is hitting with 10-15 damage, and you subtract the other Mages soak...you get -1.
The other Magi throws +30 damage, resulting in roughly 35 damage... The second magi has protect vs that form (soak+35) resulting in -1 damage...
Nobody gets killed...
Which brings us back to the original point...
Hrm. The soak bonus is 1/5th of the form score, not the whole score, so where did they pull such large soaks from 
If they were using protection spells, it's not surprising that they wouldn't be able to kill each other.
But if you feel like modifying the damage rolls by the wound penalties, sure, why not. Though once your opponent has a big enough penalty, you can just walk up to him and poke him with your finger. That should be enough to kill him.
The increasing penalties from the 50.000 light wounds should make it more and more difficult to cast your formulaic spells without fatigueing which ultimately, if they continue to fight, might lead to Unconsciousness.
Also there's the issue of potential worsening of your wounds due to continued activity with 50.000 light wounds... 
Not when you can barely walk... 
But yeah, point taken...
ahhh, Please instruct me as to where you get that information...?????
Sure...long term..but during the fight????
Well the example is a rough one and didnt include the form bonus...
One of the Mages (younger one) had a protective spell...
and was doing very little damage...
The older mage was doing large amounts of damage, but almost all of it was getting soaked...resulting in very little damage...
The net result was almost comic...
Well, since the wound penalty is subtracted from the casting total, they'll start falling in the Level-10 range in which a fatigue level is lost and the spell is cast. If they keep on, they'll soon run out of fatigue levels and fall unconscious. Q.E.D.
OK. Fair enough.
This explains that.
I can imagine.
Thanks.
I know you shoudn't check for deterioation of your wounds during a fight - but if the persons involved in the "fight" is now simply crawling after each other trying to poke with their fingers, it might be reasonable to say it is over....
Why? If you know you have a -5 to your casting total, you cast a spell that you have a bonus to it even with the minus.
In any case, almost no spell you can cast AT another magus will hurt him if you don't have Penetration...which requires a positive casting total..
(Thats why they were blowing holes in the floors...to get each other to fall to the next level and take damage...or having the cailing fall...)
But point taken...
....but it takes a LONG time and a lot of wounds to get to the point of mathmatical futility...
I agree - which is why I at times, inspired by 4th, when they strain themselves have the magi roll fatigue-rolls at the end of combat rounds.
Concerning the main problem - this is a good case in favour of a) bring a sword or learn to whack people on the head with you staff, or b) bring a mundane with a sword - bc then the wound penalties makes them sitting ducks.
No. The way that I read it, wound penalties effect all totals and rolls (page 178). A Soak roll against spell damage is a roll, and will get worse as the character sustains wounds. The first Pilum of Fire might only singe him, but by the tenth, with perhaps ten light wounds (-10 penalty), that one is going to fry him.
Matt Ryan