Joining backplates

[jacoblinnemann]

Hi guys! Im new here.

I just started building my first guitar from scratch. A parlor based on a Bruno from 1885. A huge project but loving everything second so far!

I have a question regarding gluing the plates for the back: I´ve been struggeling to plane a good join on the back (rosewood) and now its finally pretty close, but not 100% tight.. still tiny bit of light coming through a few places, but just a tiny bit.
Would this be ok? Later on i want to inlay a decorative centerstrip in the back, which im thinking could stabilize the joint and hide if the joint is not 100% tight. And the center reinforcement strip will of course keep the joint together aswell.

Is this a bad idea, you think?

Help would be much appreciated, thanks!

Jacob

[tippie53]

I like to lay the back purfling between the plates and glue them between. Never liked adding a process that you don't need. You should still use the cross grained spruce to support the joint.
There are many ways to joint a back. Learning a good repeatable process for this is part of learning. You may be taking too big a bite with the plane. adjust it a bit to lessen the thickness. You can also use a straight edge and sand them true if you need .

[jacoblinnemann]

Thanks for your answer, John. This part definately takes some practice! I seem to get better results with my blockplane instead of my no. 4 i found out.

Jacob.

[Tom West]

Concur with John on gluing stripe in when joining plates. If you get your plate edges a bit concave over their length(a couple of thou) IE touching on the ends and slightly open at the center and they close up tight with slight pressure you will get a good joint. It is also worth while to make sure your center stripe is the same size through out it's length.
Tom

[tippie53]

I agree with Rick , A stressed joint is doomed to fail. I use a granite surface plate to make my edges dead true. A perfect joint can be glued pressed together and can be taped together. The cross grain support will also support the joint to help its structure.

In the case of braces , there is enough spring in the brace to allow some flexing. I have tried the "flex" joint on a few early builds and all failed within 2 years.

The better the joint integrity the more reliable the joint.

[Tom West]

I won't argue. But have used many sprung joints especially on tops and have not had any problems. Joints that are easily pushed together under hand pressure are not under any great stress IMHO. I'll take my ball and bat and go home now.............................
Tom