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to all you seasoned french polishers out there: i have some trouble to get a uniform coloured look at the spruce top im just finishing. in use dark shellac and it looks much more dark in some places than in other (besides the fact, that my strutting pattern is clearly highlighted;). i thinking about sanding it back, but the finish is nice - besides the colour-inconsistencies - and i dont want the look of clear shellac on this one, also i cant wait, to hear how it sounds. any suggestions how to achieve a uniform colour with dark shellac, any insider tips? thanks!
p.s.: ive read in some places, that a too thick finish will affect the sound in a negative way. is it possible to get too thick with french polishing?
p.p.s.: i tried to upload a picture, but couldnt (C:\fakepath\99440BFE-E7E0-43EA-B1A5-3C1FAA1214B1.jpeg is not supported?). any guess, what in do wrong?
Tom and Vahe both produce nice tinted finishes on their French Polished guitars.
I asked Tom about his technique and he indicated he sprays the tinted shellac and then finishes off by polishing with a lighter shellac on top of it. But it would be best for Tom to weigh in as I haven’t tried his technique myself yet, although I intend to give it a shot next Blanca.
I’m not sure how Vahe goes about it, but it would be great if he gave a tutorial.
I don’t know how much experience you have with polishing so please forgive me if I say something you already know. I tend to use lighter shellacs, but to avoid getting a splotchy finish I adhere to very repetitive application patterns, so each pass gets even coverage. If I get into trouble in an area I try to avoid focusing on that area and adhere to my application pattern and let light sanding between coats even things out.
If I get into huge trouble where there is a large discrepancy in tint (e.g. a light spot from a sand through or whatever) I’ve found it’s more economical to strip off the finish and start over than to spend a lot of effort trying to recover. I’ve literally wasted days trying to blend in a trouble spot before finally giving up and redoing. Now I try to be philosophical about it and I don’t waste any time trying to recover, I just grab the alcohol, strip the panel and redo. I find the second time around it goes on quicker, maybe because the wood has some level of impregnation, or maybe because I’m freaking upset so I work faster, lol.
As for the light spots over the braces, this could point to a pressure issue during application or, more likely, a too wet fad. Maybe a bit more surface prep to even out the telegraphing could help, too.
I’m not sure if that was helpful. I’m hoping Tom and Vahe can give their opinions. From the pictures he posts, Vahe gets a really nice looking even finish with a kind of “old gold” tint.
Sometimes I've found it helpful to use a shield when polishing the bridge, so that I don't get excess shellac around the bridge. The shield is a piece of cardboard with the bridge shape cut out, which fits over the soundboard with the bridge sticking out. On the other hand, I also find it helpful to use a small muñeca to polish around the bridge and fingerboard so that I can get up close. Using colorful shellac on spruce soundboards is difficult, and I usually avoid it, or settle for beige, which is at least darker than platina but more forgiving than deeply colored shellac.
I think it's pretty hard to get too much shellac on a soundboard by French polishing in a way that affects the sound adversely. I never felt that I have. And remember that it will continue to shrink for probably months.
It's tough. I really don't use dark colored shellac on light woods anymore. It's not so hard to body it on evenly but then when I go to sand it back with 1000 grit in preparation for the final French polishing stage, a lot of unevenness appears. I've found a different way to add color when requested to; ColorTone "Vintage Amber" stain dissolved in pure alcohol and applied directly to the bare wood. You can get an even color and then just add shellac as normal on top of that and micro variations in the finish thickness won't affect the color.
Let me add that using several colors in more than one layer may give very pretty results, but in my experience it can be a nightmare to repair should need arise later on.
your right, its nearly impossible to fix a sanded light spot, but that's not my problem, its probably that i didn't polish all places with the same intensity. the braces are so clearly visible, because i sanded with to fine sandpaper before applying the shellac, i think. but yeah, your right, its a pressure issue basically. I would be really interested in vahes and toms techniques also, since im also impressed by there fresh yellow looking finishes (im experimenting with turmeric at the moment). i remember darkly, that tom has said something about his technique (clear shellac first and than add colour?), but couldn't find the context anymore.
thanks Ethan for you advise and the tip with the shield, but i haven't put the bridge on so far, so that's not the problem. you have posted a picture of your muneca some time ago, which i have to look at again (i didn't find it, can you remember, where you posted it?). I had trouble to get colour next to the fingerboard and solved it by brushing on a few coats and than even it out with micromesh. i think my mistake (one of them) was, that i haven't cured and grounded the soundboard appropriately, before starting the polishing procedere and probably i would have been come of better, if i would have brushed on the first coats.
RE: dark shellac performance (in reply to Andy Culpepper)
thanks andy, that's sounds really good! i have to give it a try next time, but i really can't wait to put the strings on, so i don't have the patience to wait for it and start again from scratch. do you have a picture of a top, that you finished with vintage amber? p.s.: your right, the finish looked great and even to a certain point of the bodying process, but than became uneven in appearance.
especially, if you have to repair someone elses finish;) so, what do you do, to get this beautiful yellow colour on your blancas? do you use dye and if so, what kind?
Your guitar doesn’t look so bad. If you are really impatient to hear it and the guitar is for your own use then why not just go ahead and complete the build. Once the bridge and Golpeador are on you might not mind the unevenness, it’s really not that bad.
But...if you do decide to strip it and start the top over, use alcohol to remove the finish (don’t sand) and maybe try Andy’s suggestion of stain directly onto the wood. Just go lightly, because a little bit of stain might go a long way. Experimenting on some scrap wood first would be a good idea.
But...if you’re going to do that I have a suggestion you could try before stripping the guitar. It might help with the unevenness, but it might make the brace problem worse, I’m not sure.
Take your muñeca/fad and charge it with alcohol only - no oil and no shellac. Gently drag the fad along the top in the direction of the grain. The idea here is to melt the existing shellac and redistribute it on the top, hopefully with the result of evening out the depth. Start with a bit of alcohol and light pressure, but experiment with increasing the amount of alcohol and pressure as you go. You have to do it to get a feel for it, but you can actually use a fair amount of alcohol and be a little aggressive once you get the feel. If you notice you are developing dust nibs in the finish it means you have used too much alcohol and the finish is becoming sticky and grabbing the dust in the air. At that point you need to stop, wait at least an hour, lightly sand out the nibs, then start again. If it works, let it cure and then you can do a final session with a lighter cut of shellac to complete the job.
It’s worth a try, but when you do something like this you always have to keep the idea in the back of your mind that you might have to strip the top and refinish. It’s not the end of the world. But accepting that you might be refinishing gives you a bit of freedom because it removes the concern that you might make a mess of it. Just look at it like it’s a good learning experience.
The nice thing about French Polish, and guitar making in general, for that matter, is the maker is often engaged in a never ending process of evolution. I don’t know how many hundreds of guitars my first teacher has polished, but the finish on some of the guitars of his that I’ve seen is as close to perfection as anyone could hope to get. Even so, he’s still experimenting and trying different materials and techniques, and that’s after many decades of experience.
thanks andy, that's sounds really good! i have to give it a try next time, but i really can't wait to put the strings on, so i don't have the patience to wait for it and start again from scratch. do you have a picture of a top, that you finished with vintage amber? p.s.: your right, the finish looked great and even to a certain point of the bodying process, but than became uneven in appearance.
Your guitar actually looks very nice IMO, besides the unfortunate brace prints. That's definitely a problem you can deal with before you start finishing. Besides using less go-bar pressure, it's not a bad idea to leave the top slightly thick for bracing and then you can surface it nice and smooth after the guitar is assembled. Some very fine cross-grain sanding with a rubber block can go a long way. Here is a guitar where I added just a bit of color to get a nice warm yellow. Nowhere near as dark as yours but you could just keep going with the stain coats I think.
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RE: dark shellac performance (in reply to Andy Culpepper)
wow, andy, that finish looks fresh and the guitar is a true beauty. i like the gerundino-like headstock. is this a new one?
looks like colortone stain is worth trying, but i find it only at stewmacs shop and its pretty expensive. but I will give it a try next time i make a order there. thanks for the hint.
rob, thanks for your advise. I already did some 'spirit coats' in between and that's the result.
Thanks, Rob! Guitarmaking and French polishing are two very different skills, and I fully admit that I'm a guitar maker first and a French polisher second. I've gotten better at it, but it seems to be a lifelong journey to perfection, for me at least.
wow, andy, that finish looks fresh and the guitar is a true beauty. i like the gerundino-like headstock. is this a new one?
looks like colortone stain is worth trying, but i find it only at stewmacs shop and its pretty expensive. but I will give it a try next time i make a order there. thanks for the hint.
rob, thanks for your advise. I already did some 'spirit coats' in between and that's the result.
Thanks! That was a custom project that I finished last winter. He really wanted that Gerundino headstock, and this cutaway design which you see on a lot of mass market guitars but is actually pretty elegant. Yeah, I've only gotten the stuff from StewMac but one bottle goes a loooooong way, probably more than I will ever need in a lifetime.
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Here's my special muñeca, which is just a thin rectangle of wood wrapped in cheese cloth and held together with a safety pin, next to my shield for scale.
Your finishing job really does look very nice, though I do see where the braces are, which gives it a sort of antique appearance.
Another thing to consider is that most of the imperfections that you see, while working under bright lights and looking for them, will not be noticeable when the guitar leaves the workbench.
Do I use dye? I never have, only naturally colored shellacs. I started out using a kind of shellac called Kusmi, which has a nice sort of caramel color. But I had problems with it because, coming in the button form, it contained a lot of wax, which I then started centrifuging out. It became a pain to do that, so I switched to other colors, sometimes "beige" sometimes "Ruby" sometimes just "Platina" or a mixture of two of the solutions. Actually, the guitar I am working on right now will have Kusmi on the back and sides. I got it in seedlac form, which seems to be well de-waxed but contains tons of insoluble stuff, probably insect parts. (I just read that seedlac is the crudest form, from which other forms of shellac are made. So it shouldn't contain less wax. I better see.) The main problem I had with wax in the shellac was that golpeadores didn't stick properly to it. Another reason I avoid Kusmi on the soundboard.
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thank you all for your feedback and tips! ethan, im quite impressed, that you get this bright yellow tone without adding something to the shellac. i decided to refinish the whole soundboard, cause im not satisfied with it (my main problem is, that the finish is so dark in some spots, that you cannot see the structure and beauty of the wood anymore and it looks kind of dirty. its worse, than one can see on the picture). so, rob, now it would be time, to try your suggestion. how do you do that alcohol wipe of-thing? and isnt it dangerous for the soundboard to put a lot of alcohol on it (collapse)? are there any other safe, clean and quick techniques to remove the shellac without touching the wood?
so, rob, now it would be time, to try your suggestion. how do you do that alcohol wipe of-thing?
This response might be way more detailed than you wanted or need, but here goes...
What I do is pour about a quarter of a cup of 99% alcohol into a bowl, put a nitrile glove on my working hand, dip a cotton rag in the bowl of alcohol and get it good and wet. I then wring it out a bit and protect the guitar from drips by holding some newsprint under the rag as I move it from the bowl to the area of the guitar that I want to address. I place the rag on the area I want to strip, get it wet, and let the alcohol sit on the spot for about a half a minute. It’s important to not let the area get so wet that the alcohol runs but, to be safe, I have another drier rag on hand to wipe any runs before they can get too far.
The alcohol will start to dissolve the shellac and it can be wiped off. It generally takes a number of gentle wipes and often a re-soaking of the rag to get it all. I just keep dipping the rag in the alcohol, wring it out, then bring it back to the guitar. Don’t worry about the alcohol damaging the wood, it won’t. Until the shellac is gone, it’s working on the shellac, not the wood. Once you’re down to wood it essentially has the same effect as the spit coat done when prepping the top prior to polish. It’s not a bad idea to not let the glue line joining the panel get too wet, however. Just to be safe, I work fast in that area, especially when it gets close to the wood, I don’t like leaving it wet for very long.
I tend to work on spots of about 9 square inches at a time (about the size of the soundhole). It’s good to start in the middle of the panel and work your way to the edges. This will give you a chance to get a feel for how the shellac will respond and will help you determine how much alcohol the rag needs to be effective. We want to avoid having things so wet that the alcohol runs over edges to places where it doesn’t belong.
It’s also important to pay attention to the areas beside the fingerboard, over the rosette, and along the binding. There is a tendency to leave traces of old shellac in these spots and that should be avoided. You want to clean everything off. Otherwise it will show when you do the re-polish. For the edges along the binding I keep the rag fairly dry and rely more on vigorous light rubbing to remove the shellac than using lots of alcohol (again, to avoid runs). When working along the fingerboard, watch the pressure and be careful not to use a fingernail to try to push the rag closer into the corner. The danger in doing that is the nail could potentially put grooves into the wood of the top.
Just an interesting aside....
I often mix different resins in with my shellac, gum benzoin being one of them. It smells nice and has the characteristic of imparting a high shine. For my last guitar I didn’t use it in the preparation and I found the shellac seemed to build up easier (and faster) than with mixtures containing benzoin.
As luck would have it, I did have to strip the top on that guitar, just a couple of weeks ago. Now this is based on a data set of only one guitar, but I found the non-benzoin shellac stripped off much easier than a shellac prepared with benzoin. With some of the guitars I’ve stripped that were polished using a preparation containing benzoin I really had to work to dissolve the finish. They were close to impervious to alcohol spills if the spill was wiped off immediately.
I haven’t done any heavy duty experimentation with this, it’s just an observation I made on one guitar, so take it with a grain of salt. But I’m thinking I might try reserving a preparation containing benzoin for the final couple of sessions, and do the bodying with a preparation that is without it.
Anyways, I think you’re making the right decision to redo, best of luck. It’s a good learning opportunity. That thread Jason linked to is well worth a read, too.
I'm glad you like the color I get with Kusmi. It seems that just filtering the solution of the seedlac takes out the wax with the other debri. The color of Andy's guitar, above, is very similar.
The way I have removed shellac from soundboards is by wet sanding using 400 grit sandpaper with olive oil as a lubricant which prevents clogging of the sandpaper. You can feel when you've gone far enough. When I have tried wiping with alcohol I got a mess, unless it was at the very end after sanding.
For sure, using alcohol can be a little scary, I didn’t enjoy the process much the first couple of times I did it, especially the first time because it dripped over onto the sides.
But it does give an automatic spit coat at the end, which may be beneficial if a tint is going to be applied directly to the wood. Even if a tint isn’t used, it gives a leg up on the next FP application. I find the second polishing job does go faster. For me, that’s good, because I think it takes me longer than it should to polish a guitar, I’m still trying new methods to try to reduce that time.
after many hours of sanding, my soundboard is clear and white again. what a sisyphos struggle! rob, thank you for the detailed description. i tried what you told me to do and nothing happened! the shellac just stayed where it was, probably because i mixed copal into the cut, which makes the shellac fast to build up, but also very strong and hard to remove. anyway, now i start again, this time with blonde shellac. ethan, did i get you right: can i dewax the kusmi by just filtering it (through cloth)? how do you avoid, that the colour of the shellac concentrates more in some spots than in others? do you just use the kusmi or do you start with a clear one? how do you avoid uneven colouredness when you sand the surface inbetween?
ethan, did i get you right: can i dewax the kusmi by just filtering it (through cloth)? how do you avoid, that the colour of the shellac concentrates more in some spots than in others? do you just use the kusmi or do you start with a clear one? how do you avoid uneven colouredness when you sand the surface inbetween?
With the Kusmi seedlac from shellac.net, I did find that just filtering it took out the wax along with the other junk. I used a disposable cone-shaped paper paint strainer that has a fine screen at the bottom. It was very slow going--seemed like I left it dripping all day, covered to prevent evaporation. With Kusmi button lac, I found that I had to centrifuge the solution to get the wax out.
If I were putting Kusmi on spruce, I wouldn't worry about doing a clear coat of Platina first, because Kusmi is so light, but it might look more even if you did. Once color is on, any sanding must be very light and with 600 grit or finer. (I don't always sand after the seal coat, before the rest.)
the surface is close again and the soundboard looks pristine white. im not pleased with that noncoloured look (especially the rosette looked so much better with the tan), but i think i will stay with it, since i don't want to do that procedure all over again and i can't wait anymore to string it up.
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