Jiuta Shamisen Dou repair

Hi, I bought this jiuta on auction for barely 70€. I wanted to repair the Dou but when I removed the old Hibiki, the Dou just separated by it’s own. So I did all the sanding job to remove the old glue,and now there’s 2 very little space between 2 pieces of the Dou. So the question is: is it ok to glue it like that, or do I need to plane it more to make the edges fit perfectly?

Hi @SanaMinatozaki

Unfortunately, sanding it was a mistake. The old glue must be removed with steam jet, or vinegar bath and gently scraping the resulting goo (I prefer vinegar, as it doesn’t affect the outer finish).

Now that you sanded it, you are very likely to need to sand it again for a perfect fit. Most importantly, you need to make sure the Dou remains perfectly squared, otherwise the neck won’t fit correctly.

However, the loss of wood on both sanding instances is likely to reduce the size of your dou by half a size, or even one full size, depending on how much you sanded.

One creative way to deal with it and avoid the size loss, if you have access to high quality hardwood veneers, is to glue a slice or two of veneer at the corner to bring it back to size. You can even use a contrasting wood for some really fancy effect (I’m thinking japanese maple, for it to look like a slice of ivory).

Finishing the added wood is easy with sanding up to #4000, then sanding from 4000 to 8000 with camelia oil (like wet sanding, but with oil).

Now you may think, “hey, great, I can make it even bigger.” Unfortunately, you need to account for the size of the nakago (the wood part of the neck that goes inside the Dou). That has a perfect fit, and any changes in the distance between the entry and exit holes will cause the neck to be a bit loose.

Ok, thank you very much for all these information. And yes it is very unfortunate about sanding.
By the way I sanded a little bit, just the glue. So yes maybe sanding a little bit the other parts should do it.
I like the idea of using a little piece of veneer.