How does one improve on the durability of a shellac french polish finish?

[beginner]

So I've got countless layers of shellac on my acoustic build.......unfortunately that one area that lost much of it's finish and pigment to something (small puddle of alcohol maybe?) is slightly improved..... but i guess that will have to be considered to be a beauty mark....like that famous supermodel with the facial mole.

I did sand like crazy, put a lot more thin coats of shellac to only minor avail.

What i'm seeing or concerned with is that the shellac finish is really delicate.

I keep the guitar elevated off the table while finishing with a cardboard box edge....As I was now starting to work on finishing the front face.

Unfortunately now the rear of the guitar body has a bunch of small scratches and/or divots or dings where it rested on a cardboard edge that i was using to keep the guitar off the table. the cardboard is not all that hard and there is little weight on it....regardless, once again i'm sanding and putting more thin coats of shellac to repair.

At some point i'm going to have to accept where i'm at...but I'm not sure how to increase the durability of the finish. I used shellac in the hope of optimizing acoustics/tone and i don't have the ability to spray etc. Plus it's safe and historic etc.

I had intended to use Renaissance Wax as a final coat but i doubt that would do much to protect from dents that seem to come from the most minor trauma.

appreciate your help, experience and recommendations.

[phavriluk]

Well, there's 'dry' and there's 'dead dry' (my wording) in lacquer-talk. One takes hours and the other takes days. I have no idea as to whether this consideration is valid for FP finishes. Experts in FP can be right useful right now in trying to guide this builder out of their dilemma.

About the cardboard - - - a carpet sample makes a real nice place to lay a guitar body on. Vacuum first. I do that and I've observed professional luthiers doing something similar, like fully carpeted service benches.

[Kevin Sjostrand]

Hello Beginner

Well I'm sorry for the issues you're having with the shellac. I'm not an expert but I have done 3 guitars using dewaxed shellac using the French Polishing method.

It sounds like you may be brushing or possibly wiping on your coats??? If you are doing one of those two applications, here is one thing that is probably going on.

1. You are building layers of shellac that will take days if not a few weeks to harden adequately to have a somewhat durable final finish. Shellac dries very quickly but there is still solvent (in this case alcohol) present in the finish which wont become "hard" until pretty much all that solvent has flashed away out of the shellac.

2. Shellac by its nature is not particularly hard even when completely dry and will scratch and dent very easily.

3. If you are not French Polishing you should attempt to do it because it will give you if properly done a harder finish because......in the FP process your are compacting the shellac as you apply many very thin coats as you build up to a satisfactory thickness which in the end will really be quite thin. .005" would be about right.

4. This finish can be handled with care almost right away but will still need time to cure fully like 3 or 4 weeks or more.

5. If your not doing FP and would like to you can get help by You Tubing Robbie Obrien French polish and you'll get the rudimentary lesson on how to do it and get you started.

This picture is a classical I did about 10 years ago. FP finish, then level sanded and had polished.

You too can do it.

[beginner]

thank you both...i am using the cheese cloth french polish technique but i'm very new to all of this...first time actually.

i fear i've been putting on too many coats too quickly....and not giving enough time to solidify and harden.

i'll change the worktop to a piece of clean carpet

I don't mind waiting if that's what it takes. Thought perhaps there was a product to apply over the shellac but it sounds like i've rushed the process.


thank you all again for taking the time to help

[jread]

I've been wanting to purchase and go through the O'Brien French polish course. Somehow in his classes, he does French Polish in one day. That seems like a miracle to me. I honestly spend more hours French polishing my guitars than building them and that's not an exaggeration. I don't mind as I enjoy the process.

I find Shellac hard enough when cured. Any finish will dent and scratch if you bang it or scratch it. Shellac is durable finish.

My 1st note to you is that I don't like using cheesecloth. I fold up white cotton t-shirt material then wrap it with another square of the same material. Some people use wool inside. I make a ball about the size of a golf ball. You want the shellac to be evenly saturating the material but not dripping out when squeezing it. Then lubricate it with mineral oil or baby oil. Throughout my polishing, I add keep adding perhaps 1ml at a time and then a few drops of baby oil. More oil won't hurt but you learn to use less over time. The goal is to evenly apply a layer and polish with a pretty decent pressure to compact shellac as you go. There aren't "layers" like nitro as each application will partially dissolve and blend with what you laid down before.

What I do, and again, what I do may not be the best way since it takes many days is to lay my guitar down on a very clean, carpeted bench but I don't lay down a freshly shellaced surface on that bench at all. After 2-3 of days, you can lay it on the bench but not before as it will end up with the marks you are talking about even if laid down on the softest of materials. Dust and whatever will find its way to mark up the freshly applied shellac. I actually put a puppy pad on my carpeted bench for extra protection when the guitar has finish on it no matter how cured it is.

What I do, is polish the top while it's laying down on the bench, then either skip the back entirely that day or tilt the body up and hold it up while it is supported on the bench only by the rim. You know, hold the guitar up at an angle so only small section of the binding is touching the bench and polish the back. It's probably better to just polish one side at time but we all get impatient.

The nice thing about shellac in my opinion is that you can just keep working and re-working it without any troubles. Even months or years later with no issues at all. Once again, I am not saying it's efficient but on my current build, I kept messing up and putting in little dings here and there and yes, you can sand down small areas but that is maddening. I have learned to just sand back the entire side if I'm dealing with deep or many spot repairs. Ideally, you don't sand through the finish unless your dents are into the wood. I use a palm sander and start with 320 or 600 and just take it all back down and repolish. You really need to pay attn to the sander marks. You can sand small areas, but I find it will take days to rebuild up the shellac in that area and I'm often frustrated with the results so for me, it's quicker to just do the entire side over.

For very small marks, scratches, and imperfections, you can try wet sanding (I use baby oil) and sand with 1000 or 1500 grit. Don't sand all the way through the layers, then repolish.

This reply is probably confusing and if so, I apologize but I've polished about 30 guitars now. None of them have been close to perfect but all of them look great. This is my style. They look vintage and I'm not trying to make perfect spray like finishes.

Follow up if you have any more questions. It takes a while but listen to the shellac and you will get the hang of it. I certainly learned by trial and error, but I will repeat: You can just keep working that polish until the cows come home and it will just keep looking better and better over time. You can't do that with sprays! Go slow, don't try to build up too much at once. I feel certain you are trying to work polish that is too thick before it's fully dry. I did that a lot at 1st. Just apply several thin sessions a day, let harden overnight and repeat.

OR just follow Bobby O'Brien's method. He's got a time machine or something and can do it very, very quickly.

[phavriluk]

thank you both...i am using the cheese cloth french polish technique but i'm very new to all of this...first time actually.

i fear i've been putting on too many coats too quickly....and not giving enough time to solidify and harden.

i'll change the worktop to a piece of clean carpet

I don't mind waiting if that's what it takes. Thought perhaps there was a product to apply over the shellac but it sounds like i've rushed the process.


thank you all again for taking the time to help

I think it's a truism that finishes are improved by subtraction, not addition. And boyoboy, that takes a whole heap of patience.

[MaineGeezer]

Yeah...there is "dry" and there is "hard." Ideally, I think I'd like to wait a week between applications and put on about 50 coats, so it would take a year to finish a guitar. I've never been able to muster anywhere near that level of patience, and it doesn't seem to be necessary as other people do it in less time. I think it mainly takes practice and developing a sense of what state the finish is in at any point in time so you know when you can apply more and when you need to let it sit for a while.

[beginner]

makes a lot of sense now....i guess that's what learning and experience is all about.

it looks so pretty.... with the exception of the little traumas.

the real disappointing aspect was it looked so nice that i thought i was done with the back and started to work on finishing the front face of the guitar... not appreciating that the back wasn't solid enough to tolerate whatever forces were tailored to the front of the guitar.

I'm going to now go very slowly, predominantly address those regions...allowing sufficient time in between coats.

at some point maybe in a 2 weeks or so I'll move on to the next stage and glue on the neck.

thanks for the kind words and the help. very much appreciated

[MaineGeezer]

One other thought: are you buying cans of shellac, or mixing your own from shellac flakes and alcohol?

I think most people mix their own. You can buy shellac flakes from various dealers - get the dewaxed - and denatured alcohol from any hardware store. Some people buy 190 proof Everclear and use that.
Ideally though you want 100% alcohol, and 190 proof is still 5% water. It is possible to get 100% alcohol, which might make a shellac that dries more quickly.

I never got that finicky -- I just used whatever denatured alcohol Lowe's sells. It might be worth trying though.

[MaineGeezer]

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