Official Luthiers Forum!

Hi, first I will introduce myself, my name is Damon, and I am new to your forum here. I am currently building my sixth dreadnought, and went all out with the wood on this one, picking out some old growth Brazilian from a local supplier, and buying some red spruce for the top.

After thickness sanding the top, a heretofore hidden sap pocket appeared. It has pretty much dried out, and is not sticky anymore, but there is a very small depression where it was, and I know this will be quite noticeable once the guitar is finished. I have included a picture, the dark spot on the left in the middle of the picture is the worst part of the depression, maybe half a millimeter deep and two mm or so long. I'm thinking I might lightly dab at it with mineral spirits to get any remaining sap before filling it.

My question is, how best to fill this? I like to put no more than 6 or 7 thin coats of nitro on the top if I can get away with it, so I don't want to fill it by spraying sanding sealer and sanding the top down, and pore filler is probably too noticeable. I am thinking superglue without sawdust.

Sorry for the cellphone quality picture!

thanks, Damon

_________________
Damon Wack
https://www.facebook.com/LindamonGuitars

Have you considered drop-filling the pocket after you remove the sap? Let some nitro evaporate and thicken, then dab some into the pocket until it fills. This will take a couple of applications. You might also consider thick CA glue which will avoid the shrinking of the nitro drop-fill.

I would not recommend the sawdust mixture as there is no way to make it match the top. It will be an obvious repair with sawdust.

Mike Franks
www.mjfranksguitar.com

Hi Damon,
That is so unfortunate. You have a few options. If it is a super nice set of Brazilian Rosewood, you might consider retopping the instrument. Personally, that is what I would do. The next best things is to simply fill will whatever finish material you are using. Be careful with CA glue because it can stain the top. If you use CA glue to fill the void, then spray with shellac first, then drop fill with CA, and then do you finish work.

As mentioned earlier, filling with sawdust is not a good idea and will make the blemish very obvious.

For the record, these kind of flaws can often be avoided in the future by holding the top up against a bright light. Any voids or hidden knots will be very obvious. You want to take you top down to about 0.140" before you do this so you can really see the flaws. Then you can arrange your guitar pattern to avoid any potential problems.

Best Regards,
Simon

Sunburst!!!!

This top was ugly so I threw a burst on it...

_________________
John Mayes
http://www.mayesluthier.com

welcome to the world of luthiery . this can be made to disappear but it will take a little time and effort. I hope you have some of the wood from the top . I take a veining chisel and pull up a divot out of the area. Then you can take a piece that you have from the top trimming and find matching grain and be sure to match the run out . Take the veining chisel and cut another divot and try and make it a bit longer.
Not you drop in the fill piece and lay a weight on it. Use wax paper to separate the weight from the wood and glue area. This should make a clean and as invisible repair. Good luck , and practice a few times on a piece of scrap , I am sure you will gain the skill in no time.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

What John Hall said, I do this often when restoring historic instruments, if care is taken with selection of the inlay, then it will not even be noticed by it's mother! You also have the advantage that you will have offcuts of the original piece, if you can take a piece from directly in line with the pitch pocket on the cut off, then it will be the best outcome you could have. Practice as John said on the offcuts first. If all else fails then John Mayes has a good backup plan!

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Thank you all very much! I don't want to re-top, too much work and money with abalone rosette and purfling. Not to mention the price of the spruce. I think it will still be a good sounding top, which is my main concern. I appreciate the advice on holding it up to the light, and if I can find a supplier near me I will certainly do that rather than ordering over the internet. I'll think about John's method, and I do want to learn how to do that, but to be honest I'm not so concerned about the look of the dark patch, this guitar is for me (finally!), but maybe I will put a sunburst on it to make it less noticeable. Maybe I'll just hit it with more aging toner. I realize sawdust would be too noticeable, I just want to fill the divot so the finish will look smooth, and was wondering if the CA glue would be the best option for that. Here is another (poor quality) picture of the back and sides. It's not the prettiest set he had, but the tap tone was amazing, many overtones and unbelievable sustain compared to the others he had, and since it wasn't perfectly bookmatched he gave it to me at a considerable discount.

Looks real nice to me

_________________
Steve Smith
"Music is what feelings sound like"

Another question: I don't have a veining chisel, and a quick search of LMI and Stew-Mac produced no results. Where would the best place be to find such a tool?

Here's another picture of the entire top, the pitch pocket is on the lower right bout (from the viewer's POV).



thanks, Damon

_________________
Damon Wack
https://www.facebook.com/LindamonGuitars

You don't need to buy local to evaluate the spruce with a good light. Do it after you receive it........you likely can return the top if it has a flaw. Even if you can't return the top, it's better to know about the flaw before you have your time invested (and pearl inlays).........and the top might work for a smaller body.

_________________
Formerly known as Adaboy.......

I would not mess with inlaying it. The flaw is close enough to the rim that you can remove the wood all the way to the rim with a straight cut joining edge. Then join in a piece taken from the waist cutoff on the same side.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

If all you want to do is fill, I suggest using a clear shellac stick. Behlen's burn-in sticks come in a multitude of colors:
http://woodworker.com/black-gloss-burn- ... archmode=2.
This fill will not change the color of the top like CA will. You melt the stuff in the divot, it cools immediately, & you can sand & evaluate the fix right away. You will get a perfectly smooth finish with this, but the divot will be visible.

Do what Howard said.

Woodcraft would have the chisel

Howard,s technique is also a good one. You will have to be careful but whether you inlay a sliver or the whole area , you will learn a new luthiery skill. These are things we all need to learn.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Thank you all so much! I think I am going to try the veining technique first, if I screw that up I know I can use Howard's suggestion! I am concerned with the strength of the area, so I think replacing it will be a good idea.

thanks again,

Damon

_________________
Damon Wack
https://www.facebook.com/LindamonGuitars

Howard is definitely on the right track. One embellishment on holding it up to a light: rig up a high-power blub behind two pieces of sheet metal with a thin slit between the two (2-3"). As you slide a top over this the sap pockets will light up like a Christmas tree and with more contrast. Good luck!