I'll get a pic of the area now that it's finished to post later today.
On using air - obviously you will need to be careful ...wear safety glasses..., this works for me,YMMV, standard disclaimers.
I first spread the crack when possible and clean it out as best I can. Think before you start digging around with a tool as you may force crap or bunched up wood fiber in, and it will stay spread apart. If it is split wide enough, sometimes I can get a sheet of sandpaper in to rough up the inside a bit. Try not to tear the paper and leave any of that in the gap.
Judgement is everything here, and newish damage will repair easier than old damage thats full of rotten wood, algae and other gunk.
I do feel that some effort to push epoxy in results in a more sound repair than just sanding the outside surface and hiding it with a fillet.
I use air at about 50psi. The key is very low ...flow.... and no "blasting" or you will be finding epoxy boogers all over your boat and shop for months... If you can still see, that is.
Gravity is your friend. Try to position the repair so the epoxy runs downhill as much as possible. I use unthickened epoxy applied with a syringe, and first force it in that way as much as I can. It will wick in quite a bit on it's own, but I like to give it a push with the air.
If you can flex the joint while doing this, even better. That really seems to help with distributing the epoxy around.
There will be a puddle that forms outside the crack. Approach this slowly and from a distance with a plain old air squirter ...just barely... cracked open.
Low, low flow is the secret. You will find that you can actually form tiny ripples on the puddle and sort of wash these into the gap. Hold a rag in your other hand as a splash deflector just in case.
Wipe off the excess epoxy, and when it's cured fill any remaining gap with more epoxy that is thickened with the filler of your choice. (I use wood flour)
Someday I will make up a needle valve with quick couplings to install in the air line just ahead of the squirter. This will allow pre setting the flow so I don't have to be quite as careful with the squirter, some are hard to modulate well.
On painting- we planned to roll-and-tip with a single part poly, but may consider having it done professionally with a 2 part. I was told by a previous owner that it is currently Awl Grip. Paint is mostly ok but there are many small repairs. Plus it's an ugly pale yellow. Wife/helm wants red. She usually gets what she wants...
I agree... looks awesome. It's looks more like a grand piano than a boat. Blowing epoxy into the cracks is a great idea! Do you just use the regular air squirter attachment from a distance? That sounds like the best way for me to glue a piece down on my boat.
Will you be painting this thing, and how do you plan on doing that?