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I have French polished my guitars until now, and I'm in the midst of my first Silvertip/Enduro Var finishing job. The filling with Silvertip went well; a few extra coats were needed to get one where I didn't sand through, but it looks good now.

My question has to do with some small cracks/voids in the colored veneer strips I used to make the rosette. Here are some photos:









When I was French polishing, I would use stick shellac to fill things like this before I started trying to build up shellac on the whole top. But General Finishes recommends against trying to put Enduro Var on top of shellac.

I can think of a few options, but I want to see what smarter (and more experienced) people than me think.

I can use Silvertip on the rosette, using an artist's brush. But I am a bit concerned about how that will affect the spruce. I smeared a little Silvertip on the purfling lines around the edge of the guitar while I was filling the sides, and it worked out OK, but I sanded it back to wood on the top rather than leaving a film of Silvertip, because I didn't like the color of the Silvertip on the spruce. I guess I'm worried about staining the spruce, or having a color mismatch on the spruce right next to the rosette.

I can go ahead and use stick shellac, but as I said, I'm worried about putting Enduro Var over shellac.

I can put some coats of Enduro Var on the top and then drop fill with more Enduro Var.

I can put some coats of Enduro Var on the top and then drop fill with CA glue. I'm definitely not going to do this on the raw spruce, but only after some finish is on it, if at all.

I can put some coats of Enduro Var on the top and see if it can be applied thick enough (just on the rosette, not everywhere) to fill in those cracks. I have doubts about this, but maybe some folks have had success and I just don't know about it, since this is a new product for me.

There are probably options that I have not thought of.

I look forward to any suggestions that you might have for the best way to fill these little cracks. Thanks!

From your options I would fill with CA sometime in your Enduro Var application. I never used Enduro Var but I have found attempting to fill voids with thick coats of top finish looks good for a bit but sinks as the thick coat cures. I have filled gaps with 2 lb shellac, but that process is many normal layers sanded back each day.

Another not mentioned option is hot hide glue.

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http://www.Harvestmoonguitars.com

I know GF don't recommend shellac under EV, but they used Bullseye sealcoat for their test panels.
I've had zero problems with made up shellac, some guitar for several years now and GF said if you're going to have adhesion problems they will show up quickly.
Having said that, I'd try CA, but inlay some pieces in scrap, suitably crack them, then try a CA fill.
I don't think it will be noticable, a test will let you see how ir works - just seal with shellac before CA gets into any spruce.
HHG as a fill may be softened by the EV.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Colin and John--

I will probably not try hot hide glue as a filler, for the reason mentioned by Colin. I put this guitar together completely with hot hide glue (no other adhesives at all), and while I trust waterborne finish to not cause problems with my normal glue lines, I don't think I trust waterborne finish over large bits of dry hide glue used as a filler.

It is great to hear that you have not had problems with flake shellac under Enduro Var, Colin! I have missed using shellac as a protective film during construction of this guitar. Life would be a lot easier if I didn't have to worry about shellac/Enduro Var incompatibility. Maybe the simplest solution is to just go ahead and use the stick shellac in my normal fashion.

A quick test and brush some EV wouildn't hurt, never used stick shellac myself.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I used EnduroVar for refinishing an upright bass recently. After 3 days of 3 coats, then level sanding w/400, generously dropfilled pits and fisheyes with the EV, waited 3 days, leveled again and finished up with 2 more coats. Worked fine.

Carl--

Good to know! I have some follow up questions:

1. Was that a total of 9 coats (3 coats per day over 3 days) before the level sanding, or a total of 3 coats (1 coat per day over 3 days)?

2. Did you use a pipette, toothpick, or something else for the drop filling of Enduro Var at that stage?

I appreciate the guidance!

3 coats per day. I level sanded each day before spraying the next 3.
I drop filled using a tool I found in some artist supplies left by my son 30 years ago, a pen tip from a Staedtler Masterbow. The tip spacing is adjustable. Here's a pic.

As a footnote, GF indicates EV takes about a week to dry, and shrinks during this period noticably.
The drying period is extended with thickness, or extra coats.
A further 3-4 weeks is required for it to cure fully, and shirinkage is not so noticeable during the curing period, but does still happen slightly.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Yes, I waited two+ weeks before final finish sanding (800-2000 and micromesh to 6000), then buffing and polish with a pneumatic rotary buffer. One of the shiniest finishes so far.

I wound up using the stick shellac. It looks pretty good under some naphtha:



There are a few very tiny spots that still need filling, but I will either give them another round of stick shellac now or wait and drop fill as needed later.

I wanted to go ahead and get the bulk of this done now before I apply the Enduro Var, because I am trying to discipline myself to solve cosmetic things as early as possible, rather than trying to fix them later in the finishing process. I tend to like the results better if I solve problems early.

I appreciate the guidance by all who provided it. Things will move faster as I get more familiar with these products that are new experiences for me (Silvertip and Enduro Var), but for now, I'm being cautious and fairly slow.

Looking really promising.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

The stick shellac looks great! I have a set of sticks I use for fill and repair, I think I will now use it on the rosette. I just never though to use it in that application. I love the stuff as it is not as hard as CA so much easier to level.



I would vote for fixing it now. Bit by bit I have also learned that early is better. Lately my goal before I start applying top coats is to start with a guitar that looks finished.

_________________
http://www.Harvestmoonguitars.com

Amen, John. Ounce of prevention, and all that.

I had bought two nicer non-electric burn-in knives not long ago (better than the one I used for a decade), along with a small alcohol lamp. These tools make application of the stick shellac a very relaxing, quiet job. And I think I'm getting better at it, because I am leaving less of it on the guitar to be cleaned up than I used to.

Leveling is a bit of a different story for me. It takes me longer than it should, because I always seem to be sanding when I ought to be scraping, and scraping when I ought to be sanding. Just my skewed perception based on impatience, I guess. In the end, it looks good and it's level.

A few things that could be helpful to some folks (on my mind as part of this filling job):

1. For a soundhole plug during finishing, I started out using a circle I cut out of one of those really thin HDPE cutting boards, sprung in place by a piece of foam underneath. I have a bunch of those thin cutting boards for general use in the shop. But I switched to using a lid from one of those little containers of spreadable cheese, turned upside down. This gives me better access to putting finish on the inside lip of the soundhole, because it sits slightly under the top (as opposed to the flat plastic, which abuts the bottom of the top), but still seals off the inside from the outside (good enough, anyway).

2. This one is gold: While hand sanding with any grit of sandpaper, keep a file cleaner brush handy (the kind with metal bristles on one side and regular brush bristles on the other side). When the sandpaper loads or gums up even the slightest bit, give it a swipe with the regular brush side. If the gunk is still there, give it a swipe with the metal bristle side. My sandpaper lasts as long as I want it to when I do this, and it craps out on me in a few moments when I don't. I never sand without my file cleaner brush at hand.