Block vs magic block

[vader1958]

So my question is can you both use a sheild from a magic item and roll a athletics for standard block? Example my wife char. was in a doorway a wiz blasted her with spell. on her previous turn she stated I put up my sheild from her magic item block 4 now can she still roll to dodge and if so would they stack? or because she said she put up sheild she has to use that or does she dodge then if she fails then the sheild kicks in? Thanks for the help
V

[Haru]

does she dodge then if she fails then the sheild kicks in?

Essentially, this is it. A block is a preemptive defense roll, if you will, and you can use it instead of your actual defense roll. You can do so even if your defense roll was successful, but since the attack was already prevented, that would be rather silly, most of the time.
You don't have to use it though, you can always just take the hit instead, if you want to keep the block up for something else.

[Tedronai]

Defense (ex. 'dodge') rolls do not stack with blocks, but they can be overlapped.  Whichever of the two is better will oppose the attack.

[Wordmaker]

Yeah, very few things stack in DFRPG, with the major exception of bonuses from invoked or tagged Aspects.

[InFerrumVeritas]

HOUSERULE WARNING

One thing my group is going to play with next session is converting a block to a bonus.  So if you roll a really good defense roll, you can get a +2 with the block as if it were an aspect.  Possibly +2/every 3 shifts.

This would only apply to blocks created as an action, not enchanted items used instead of a defense roll.

[Lavecki121]

That's what fate core does with "create advantage" essentially