Worked this weekend on my 3rd bow but the first with lams I grinded. Ground a .174 parallel out of Ipe for the back, a .030 uniweft glass core and a .174 taper of .002 for the belly. The back side of the riser has a good bit of curve to it and the scarf joints of the lams kept separating when I compressed the lams into the form. I cleaned the ipe with denatured alcohol, used a 45 degree compound miter for the scarf. Tried the gel Titebond super glue and 5 minute epoxy. Any suggestions on better scarf joint success?
I've found a 45 degree joint doesn't give enough surface for a strong bond.I tape my lam butts on top of one another and grind them on my belt sander to about a 1/2" flat spot on each lam. As long as your grind is square they will mate perfectly. You can check your grind by putting a square line on the tape and grinding to the line. I check the fit with a long straight edge(6'level) and put super glue on one piece and spray the other with accelerator.Makes for a quick bond so be sure they line up before pressing them together.The lams are ready to sand off the excess glue in just a few minutes