I like a method I seen on the Tommy Mac Donald show, "Rough Cut" PBS. He makes blocks that He glues on the outer edges of each board. Then by taking clamps and tightening them on the corners draws them together nicely, and You can see each glue joint perfectly. The blocks have 3 sides One 90 degree and one 45 degree edge. Putting a clamp on the two glue box 45 degree edge gives You the terfect gluing line. Use a softer wood, and any bits and pieaces that remain on Your frame after chiseling off the glue block, can be easily planed off!
John 3:16 Please fill out your profile, It helps us to know you better