I must have stared at that circuit in my breadboard for hours yesterday, and missed one obvious truth; I had R1 & R2 switched. I reckon I'm lucky I didn't fry the pi.
Taking it apart and putting it back together helped. I'm getting a nice burst from irsend now.
Now to solder the circuit together, and not make any stupid mistakes like that again!
where everything goes, and am about to cut my sections off the main piece before I solder it.