[szicree]

So how much baffle seal material should there be above the baffles?? And what the heck do I use to sew the corners together if required?

 

[N131RV]

Height varies

You want enough that a nice seal is formed when the cowl pressure pushes the baffle material against the cowl. Typically, you need enough to close the gap, plus about an inch and a half for the "seal".

I just used safety wire to lace the corners together. Put the twists UNDER the seal so they do not contact your cowl and rub a hole in it.

Just MHO, YMMV, etc

 

[bsacks05]

You want sufficient clearance between the baffle and cowl so that the baffle material is not creased too much against the baffle when the cowl is installed otherwise, the material could be cut by the baffle.
I used some leather shoelace to tie the corners but recently removed it because the material has taken a set and the lacing is no longer needed. In fact, most baffles I have seen do not have any lacing.

 

[N916K]

And what the heck do I use to sew the corners together if required?

I just taped the corners together for the first few hours of flying. The material takes a set fairly quickly if you leave the cowl on after you fly.

 

[dan]

Ditto on masking tape to hold the joints together/where you want 'em while they take a set. I got that tip from Gary Sobek and it worked great. Pulled the tape off after a few flights.