Just confused on the timing of when an Artificer can infuse an item. Can it only be done at the end of the long rest? Can it happen at any other point through the day? Is an instant effect that can happen in combat?

Can I piggyback here and ask about Infusions? In relation to the 2nd level Infusions feature:

"Using this infusion, you replicate a particular magic item. You can learn this infusion multiple times; each time you do so, choose a magic item that you can make with it, picking from the Replicable Items tables below. A table’s title tells you the level you must be in the class to choose an item from the table."

What is the mechanics of this feature? Is it simply that I can make a magic item that I have chosen to replicate? I am guessing I need to have the item that is to be infused. For example, a carrying sack to infuse it as a bag of holding or a pair of goggles to infuse with nightvision... is it that simple? Thanks!

Quote from clear_seeker >>

I am guessing I need to have the item that is to be infused. For example, a carrying sack to infuse it as a bag of holding or a pair of goggles to infuse with nightvision... is it that simple? Thanks!

Pretty much - yea.

 Another piggy back question

"You must touch each of the objects, and each of your infusions can be in only one object at a time." So, normally you can only have one infusion at a time (i.e. only one AC booster, one Attack booster and one humuclus).  
When you're making infusions in the morning, Can you choose to infuse one of your currently in use infusions?  I.e. make a new humucluus with a different crystal, or chose to infuse your friends weapon instead of yours?

I'm asking because, strictly speaking, if the infusion can only be on one object at a time, and it doesn't seem to say "creating a new infusion ends the last one" or something similiar. Means that if I have one in existance already-I have to make other infusions until the old one disappears.  But because you make all the  Infusions at once. 
Doesn't that mean you have to wait wit ha day between before you can make that infusion again?

i.e. 
day 1 infuse me sword.
Day 2-I want to infuse my friend's sword, but I can't because mine exists.  So I infuse 2 new o bjects (which ends the 2 previous ones).
day 3: infuse two new objects ( ending day 2's new objects) one of which is my friend's blade. 

"Whenever you finish a long rest, you can touch a non-magical object and imbue it with one of your artificer infusions, turning it into a magic item. "  or does this line work differnetly? As it has no limit or  time, you could "instantly" rotate through all 3 days in one instance, just cycling through several "redo" until you get the combination you want?
Seemingly there is no way to prematurely end an infusion of your own violition. so it seems like it has to be one of those two options?

I mean you could break the item first I guess (or kill the humucluus), the night before or directly after your long rest, then remake them that way.. but that sems illadvised.

I guess it depends on how you interpret this part of the infusion text:

each of your infusions can be in only one object at a time

It could mean that if you have a particular infusion active - you can't infuse another item with it at all until it's not longer active. Or it could mean that if you infuse a second item with that infusion - the first version of that infusion immediately fades.

I would go with the latter personally because otherwise it feels overly restrictive - but I don't know if that's RAI.

Yeah. i automatically read it as assuming I could infuse the same thing again-and it would just overwrite the currently existing one. 
but someone on reddit brought that up and I realized I kind of just been auto assuming but the wording is actually kind of awkward.

Up to this point, I had actually been assuming you could voluntarily end infusions on command, and that you could voluntarily end magical tinkering.
I realize now that you can't... Effectively you can never turn off your abilities outside of destroying the item.  it feels very weird. Once you use a magical tinkering... you techincally can never not have it "in use"   Weirder still if someone steals your magic item you can't turn it off (until you long sleep and replace things---which would require you to have  enough targets to make new ones since You may or May not have to have "mundane" versions to enhance first. Depending on how its read)

it feels very awkward to me when I realzied that so much of it can't be turned off by your own will.  

Quote from Emmber >>

I guess it depends on how you interpret this part of the infusion text:

each of your infusions can be in only one object at a time

It could mean that if you have a particular infusion active - you can't infuse another item with it at all until it's not longer active. Or it could mean that if you infuse a second item with that infusion - the first version of that infusion immediately fades.

I would go with the latter personally because otherwise it feels overly restrictive - but I don't know if that's RAI.

I'm not sure I would say that it's "overly restrictive," because it doesn't actually prevent you from putting the infusion in a new item. You can just keep infusing new items with your unused infusions until the one you want fades and you can use it again. That kind of musical chairs nonsense would be incredibly obnoxious. Since this interpretation only means that doing the thing would be really stupid rather than impossible, I think it's safe to conclude that RAI is that yes, you can infuse a new item with an in-use infusion, and the old use just fades.

As to the magical tinkering feature, my understanding is that technically need to spend some time each day to maintain the item, so if it's stolen, lost or given away it kind of just stops working eventually...

Quote from Terrie >>

As to the magical tinkering feature, my understanding is that technically need to spend some time each day to maintain the item, so if it's stolen, lost or given away it kind of just stops working eventually...

 Nope! Your magical tinkering stays active on an object unless you touch it again to deactivate it, or if you magical-tinker more objects than you can have active at once, the oldest one deactivates.