Glad Jim was able to put your mind at ease.
Hair line crack bottom back of walnut McSpadden
I did hear back from Jim Woods and he said that those were superficial and in the wood all along. It was not a result of damage and will not get worse. If the dulcimer was unacceptable to me, he would allow me to keep it until another one was made and shipped to me. I told him that I love the sound and wanted to keep this dulcimer instead. When asking about varnish, he told me that I didn’t need to do anything to that area of the dulcimer. If I wanted, I could use furniture polish that did not contain silicone. Old English (in the bottle) would be fine. Jim Woods of McSpadden Dulcimers was really helpful. Thanks everyone for your input, too. I have been playing the dulcimer less than a year and still have a lot to learn about these wonderful instruments!
Thanks to everyone! I agree with every comment. I did send photos to Jim Woods and asked suggestions. If I ever need it repaired, I will go to a dulcimer luthier. It makes my heart full to know that I have such a great sounding instrument. I will definitely take great care of it. Going to let you all know what Jim Woods says in his response. He has always been great about any questions I have had in the past while making the two dulcimers that I have from McSpadden.
If I read your post correctly, you are the original registered owner of this instrument and as such that dulcimer has a lifetime guarantee. I think I would consider sending Jim Woods the pics you posted and inquire as to what he thinks should be done to correct the issue. It maybe that that separation around the knot may just require a bit of finish or something of that nature to secure what may simply be due to the wood aging a bit.
I understand the tone issue you mentioned too as I have redwood/cherry and it is really outstanding and is just as balanced and bright as some that cost considerably more.
Anyhow, what have you got to lose?
I agree with those who suggest not doing anything, at least for the time being. Other than some minor cosmetic issues, you don't yet have a problem. At this stage, your dulcimer is simply developing a little character. If the seperations turn into genuine cracks, they can be repaired.
As Bob says -- it "ain't broke" so don't try to fix it. Especially since you don't know what Cyano Acrylate "superglue" is -- you'd be apt to glue your fingers together 
! You need to ask McSpadden what they use for "varnish" -- it could be any number of things like polyurethane, varnish, shellac, various oils.
As Bob says too, those truly do not look like cracks, they look like grain going around a knot. Since you say there's no light coming through cracks, gluing would not help. Those marks could have been there since the beginning, and you're just noticing them. I don't even see any evidence of the "varnish" cracking there.
It NOT as if McSpadden, or anyone who builds dulcimers goes deliberately out of their way to hide imperfections, as your luthier suggests! That said, darn few of us builders can afford to just cut the back off and scrap the instrument or replace it. If there had been real cracks, McSpadden would not have sold it. Or they would have fixed the cracks and then sold it as a defect instrument.
Word of advice -- do not take your instrument to any old luthier for work unless absolutely necessary. Always talk to someone who is a dulcimer builder/luthier. Dulcimer are NOT guitars, they are not built the same way, they don't make sound the same way as guitars. mandolins and such like; and they are not 'set up' like those other instruments either.
Silverstrings, I would offer a wee suggestion: Don't panic!
I was imagining cracks along a straight grain, but from the pics these appear to be around a knot section in the board. Are the hairline cracks actually going through the boards? If so that can be remedied. They look superficial from the photographs and I might imagine they will remain superficial. Give it time, keep it in a regulated environment like you have been, and out of the direct sunlight and see how it does. If it sings as beautifully as it does, leave it alone, it ain't broken. Instruments in far worse condition are played regularly; just be tender with it.
~Bob
Thanks, Ken. My husband, a jazz guitar teacher thought I should possibly get a replacement dulcimer. I did explain that I tried out every dulcimer by various makers at a recent festival and not one compares to the sound and balance that I get from this one. I wonder if they knew the wood had problems or that it just happened with this wood. Thoughts on that? The luthier said that there is no place to put the glue. If it gets worse, he would fix it for me. What is CA “superglue” and what kind of varnish would you suggest? Thanks Ken, for any input. My brother is an award winning sound mixer for Sony Pictures and even he says that he has never heard such a “magical” instrument!
Not much McSpadden can do: replace the instrument is about it. If they put new back on it will probably wipe out the "unbelievable tone".
They could dribble some very thin CA "superglue" into the cracks; let that dry, and then cover with additional "varnish". But you can do that at home just as easily and just as well. That's what I would do.
So, I live in North Georgia and am very careful with my Redwood/Black Walnut McSpadden. It has been a mild winter. I never leave it in the car. I take great care of it. I have only had for 8 months and noticed on the back bottom part of my dulcimer a few hairline cracks. I will call McSpadden as they made it for me. I did let my husband show to his luthier. The luthier says that sometimes makers see a problem in the grain and don’t want to remake it so they cover it up. I really love the sound and no light is coming through the wood. I want to approach the right way with McSpadden. I don’t want to give up this dulcimer and get another. The tone is unbelievable. However, I have never had this problem with a guitar. I feel like I am already very careful with this instrument. Suggestions are very welcome. I worked hard to get this wonderful instrument and can’t go out and buy another. Thanks.
