Yeah... balloon. That's a GREAT idea!.
Loose back brace solutions
A balloon! I hadn't thought of a ballon. Thanks.
I lucked out again in that area - there was enough residual glue on the edge with the side to hold it (that is what was making the cracking sound when pressing on the 7th fret area). I pushed on the 7th fret area, got it got it to pop/crack open, got the glue to the area, waited a while and used a bent rod to pop it back. Otherwise I would have had to use a balloon or bent stick to hold it in place.
Ooh, a spy camera! And maybe a robotic arm? I'm afraid my repair tools/toys aren't that hi-tech. 
Did you make any effort to clear out the old glue or somehow clamp the brace while the repair dried?
I just had that problem last month. I had a brace loosen under the sound board near the middle of the dulcimer. The lose end would make a cracking noise when playing around the 7th fret. I had heart shaped holes so I could actually get a small camera and a long shrink tube with a wire backbone to get the glue to the spot.
Thank you, Matt. Those cross braces seem to me to be more a construction aid, helping to keep the shape, than a source of strength.
John, yea, most braces on mountain dulcimers are like bicycles for fish. If you can safely take them out through the sound holes it is probably a good idea. If the brace needs to stay, I usually drill a small hole in the back and glue in a dowel plug when done. The guys at Folkcraft have done some cool work with laser cutting figures to glue in the holes after fixing, but that requires a good laser cutter.
If you are working on a baritone or bass dulcimer, carefully consider before removing the brace. The larger sound board may need them. Also consider the choice carefully if the soundboard is spruce, cedar or other softwood. Those board may need the extra support.
PS. I am not your standard dulcimer maker and will probably put some people's backs up with my comment on bracing. Conversely, I brace all of my instruments as I do not attach the fretboard to the soundboard. To each their own.
Hi. Since I acquire used instruments I often have repairs which need to be taken care of. A particular problem for me is the issue of loose braces. I'm curious how people go about reparing them. On a flat-top guitar I can usually work through the soundhole. But dulcimers are too shallow and the soundholes are too small to do this easily. I'd like to hear how people address this problem. Do you take the backs off, the way a violin repairperson might? Or do you work from the outside, with small holes, glue-and-screw, to be replaced with small dowels? Or do you simply take the offending brace out? They really don't do much and I see Warren May and other makers don't use them.
Please teach me. Thanks. 
