Cuban Mahogany and Lutz Spruce 00

[Darryl Young]

Trying something a little different. Instead of sealing the top with shellac, I'm going to try Damar. More flexible than shellac and pops the grain better. I just mixed a 2lb cut in turpentine (2oz in 1 cup). I'll likely prep and shoot the soundboard this weekend to protect it while scraping the sides, cutting the binding channels, etc. if for some reason I don't like it, I can sand it off and re-shoot before finishing.

[Kevin Sjostrand]

never heard of Damar.

Kevin

[Darryl Young]

Sprayed Damar on the top yesterday after sanding with 220g. The Damar is from Singapore is is made from gum or sap from a tree (if I understand correctly). It really pops the grain and that is what I was hoping for! Maybe I can post a pic later if I can get one that captures how well it pops the grain. It really sets off the silking in this top.

[Darryl Young]

The Damar looks sprayed great and looks nice! I started out spraying a little too "rich" and had to cut down the feed rate of the Damar solution a bit. It really pops the grain nicely. I mixed it in turpentine and it dried fairly slow......about 2 days. Next time I'll try dissolving it in mineral spirits as I think it would cure quicker.

I think the Damar looks nice. It had a bit of a yellowish shade in the Mason jar I mixed it in and this gave the top a bit of a tint. Here is a shot of the top......what do you think?

[Kevin Sjostrand]

It looks just fine Darryl. Any other advantages to using the Damar?

Kevin

[Darryl Young]

Kevin,

I'm not really an expert on Damar so take what I say with a grain of salt. Andy Gamble has used it but this is my first time (and I haven't yet sprayed over it).

With that said, artists use this over their oil paintings because it 1) brings out the colors in the painting 2) it stays fairly flexible so it takes a long time before it cracks. Considering how flexible a canvas is and how much likely moves with changes in pressure or air movement from a heater or AC unit, that is saying something. Also, the paint expands and contracts with temp changes. 3) It resists yellowing more than most sealers/finishes. 3) It may be more UV stable than shellac.

So does that resistance to cracking with age due to movement translate to a guitar top/back? I guess time will tell. All finishes disentegrate over time and I'm sure this one will too given enough time. I would like to think it will last as long as anything else. Read more about it in this old thread on the OLF that peaked my interest in trying Damar (click the link below):

Popping the Grain

[Darryl Young]

I will try to get this thread updated over the weekend. I've been out of town a LOT lately so haven't had time to build much or especially no time to post. Also, I had a lot of good pictures on my phone intended for this thread (that I unfortunately hadn't backed up) and over the summer I accidentally went into the ocean with the phone in the pocket of my swim trunks (did I ever mention how "smart" I am??? <smile>). So I bummed out and haven't posted on this thread much since.

Anyhow, til I update the thread, I have a question hopefully you guys can help with.

This is my second build and on both, I positioned the neck block right where I thought it should be.......meaning, I positioned the neck block where the neck would be above the top of the side roughly 0.090"-0.100" so that it would align with the top of the soundboard once it is glued in place. On both guitars, the neck ended up proud of the soundboard so I had to elongate the holes in the neck block so I could move the neck down low enough to align with the top of the soundboard. To do this, I also had to sand off some of the bottom of the neck tenon then re-round it. I'm guessing what I did wrong is is not allowing for the taper of the rim/sides above the soundhole to allow for the fretboard extension to lay flat. Tapering moved the top of the rim down leaving the neck proud. So I'm curious, how much others here allow for neck taper when positioning the neck block for glueing?.......0.020", 0.030", or what?

Second question. I need to trim the heel of my neck to finish fitting to the body and setting elevation. If I trim even with the body binding/purfling, there will be very, very little heel left below the tenon. I will be gluing a black cap (for a purfling line) and a cocobolo cap on the heel so that will be addtional thickness added. So my question: should I trim the heel so close to the tenon? If so, should I sand/chisel the mahogany below the tenon back so it never comes into play while fitting the neck......and then just sand the black purfling and Cocobolo cap to fit against the body? Alternatively, should I leave the heel a bit longer and the black purfling line and cocobolo cap won't align with the black purfling and cocobolo binding? This would give me room to chisel a "trough" in the mohogany neck below the tenon still leaving a bit of mohagany full depth.......so when I fit the neck to the body, I'll be sanding coco/purfling AND mahogany when fitting the neck against the body.

I'm leaning toward cutting the heel short (where I like it, aligned with the binding and purfling). I think if I only remove the mahogany right below the tenon (not on the sides), no gaps will show on the exterior. Thoughts?

[Darryl Young]

No recommendations so I'll move on.

Earlier, when trimming the lining to accept the UTB, I didn't take the time to set the lighting up properly and cut too far and went into the side. Bummer. Worse it's in the upper bout on the side that faces the player, yikes!

Here is how that repair went.

The damage:

IMG_0880.JPG

Removed the thin area and used a quarter to trace an area where I'll replace the wood:

IMG_0884.JPG

[Darryl Young]

Used the same quarter to trace a plug from scrap off the sides and glued it in place. Note the plug is thicker than the area I removed with my inlay air tool so it stands proud:

IMG_0890.JPG

And hear is what it looked like after sanding level with the side. This is in the upper bout on the side that faces the player so I'm glad the repair isn't too prominent.

IMG_0891.JPG

[Darryl Young]

Binding took awhile. One, because I'm a slacker <smile> Two, I've been out of town a lot lately. Three, it's the first time I've tried wood bindings and I had a little to learn.

I posted a pic of the cocobolo binding material earlier. I cut the coco to size on my tablesaw. I placed a block of scrap wood on top of the coco and clamped it to the fence so the binding fit tightly against it while cutting and this worked well to trim the binding to width.

I glued (2) 0.020" thick black purflings to the bottom of the binding for a black purfling line 0.040" thick. The purfling was the dyed maple stuff from StewMac. I used fish glue for this. In hindsite, I should have left the binding at excess thickness, glued the purfling in place, then sand binding/purfling together to the final thickness. I then bent the coco with purfling on the Blues Creek bender with no issues.......except I didn't center the binding very well. Ended up it was short on the lower bout for the back and was just barely long enough for the top. I tried re-bending the two pieces for the lower bout but they were "cooked" when I was done........so I had to buy more coco binding from Hibdon and bend two more pieces. Paid more attention this time and they came out perfect! Anyhow, this took awhile.

Here is a picture of the herringbone purfling in a sandwich ready to bend. The wood is ash thinned to the same thickness as the width of the herringbone. This went great after watching John's YouTube video of bending purfling.

IMG_0933.JPG