Acoustic Guitar Construction

I’ve finished my 3rd guitar with great success. My son is already bugging me about building him a 12 string. Anyone here ever build one? How much more difficult is it? I assume the neck needs a lot of reinforcement?

Hee Andris,
It is almost the same as a dread or jumbo. I made a few. Look on my site at no 33, 35 and 38. ( it is in Dutch, but you will manage to get there.)

-You need a bit wider neck for all those strings. (I used 48 and 49 mm), therefore the neck is beafier from itself than normal.
-I advise carbon strips (8x3mm) that will help in keeping all straight.
Those two will do for the neck.

-In the body I used an extra tonebar and a larger bridgeplate. And I started the top thickness at 3.2mm (0.125").

And 'that's about it.

Good luck, go for it.
Oh....and all those guitars are still intact after 6 years.
Herman

Intonation is always a trouble on 12 string factory guitars. They don't have the time to get it spot on.
If you make a wider saddle (lets say 4-5mm) you have room to adjust for every string. Not that delicate looking, but it brings joy when all is right in the end.

Here are some sounds of no 33:
Sound 1
Sound 1

I've built two. Figuring (hah!) that I had some headroom by using 6-string conservative bracing and adding an eighth to the (now 5/8") x-braces, I set to work. Both turned out wonderfully. DON'T OVERBUILD. You probably are already overbuilding your 6-strings and factory guitar should not be used as examples. Both of mine were Martin long-scale minus the first fret joined at the body at the 12th fret. I wanted compact and comfortable 12-strings and I got two. One's been lent to a friend and the other is sitting in its TKL Classical Size hard case. Fits just fine. I couldn't be happier.

As for the extra work, I didn't find much, and that was taken up by twice as many tuners and bridge holes and slots in the nut.

Don't lose sleep and enjoy the ride. Prepare to be amazed.

Ok…I’ll definitely give it a try. Thanks.