It sounds like you have the right idea, AC43 gives good guidence, a
good repair job can potentially be stronger than the original stock

See Page 1-15 of the link
http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2001.pdf

Doug

On Jun 3, 6:23 pm, Lou wrote:
I was working on one wing when the other wing (and I'm guessing)
vibrated of the supports onto the concrete. It broke the end rib which
I will have to build a new one. but it also broke one of the two 3/4 x
3/4 parts for the rear spar 12" from the end. Any ideas on how to fix
this? I'm thinking it's going to take cutting the broken part out in a
scarf style cut and replacing with a scarf joint, then sistering
another part onto the inside. Then just for the heck of it T-88 a
piece of ply across both parts at the joint. Anyone want to comment?
Lou