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 Post subject: French Polishing
PostPosted: Sun Apr 05, 2020 11:46 pm 
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Joined: Sun Mar 09, 2014 8:13 pm
Posts: 2248
Hi guys,

I know we have some folks starting their first french polishing. I'm going to talk about how to correct those swirlies that sometimes appear. Those who are better, probably don't get little boogers as they polish. Well, I still get some.

First, check to make sure your pad is clean. Even with the best efforts, I still get dirt on my pad. I keep old tshirts for polishing. I cut another piece to cover the cotton, and put my shellac soaked cotton wad in the clean cloth. I do this automatically, before spiriting off.

I've learned that some guitars seem to need more polishing than others. I've learned to start reading the shellac. When it appears that I'm moving the shellac around, rather than depositing new, it's telling me that it's time to start spiriting off.

Spiriting off is simply adding drops of alcohol onto the shellac you've added to your pad, prior to polishing, therefore diluting the shellac. The increased alcohol will melt the shellac already on the guitar, blending in the new shellac. It also starts to melt those boogers away. In the beginning, you'll still be building up the finish, just not as quickly. This is also the time when you can really compact the shellac, thereby making it harder.

When I start spiriting off, I put about a dime to nickel sized amount of shellac on my pad (still working with a 2# cut). I then add 2-3 drops of "dirty" alcohol. When you're French polishing, never use pure alcohol on your guitar, to spirit off. I keep about 1/2 cup of alcohol in a jar, which I've added some shellac. I add about 3 transfer pipettes of shellac to new fresh alcohol (~1 teaspoon).

After putting some shellac+alcohol on your pad, add a scant drop of oil, so the pad doesn't stick to the finish. You'll read that you have to be careful about the amount of oil used.

I say, use what you need to keep the pad from sticking.

As you gain experience, you'll use less and less, but more doesn't hurt. The oil will work it's way to the surface. It might take longer for it to come out, but it'll come out. Oil can obscure the true surface of your shellac, masking the swirls. Trust me, you'll see them as you wipe away the oil. The oil that's being given up to the surface can act as lubrication; you won't need as much oil on your pad. But, if that Puppy starts sticking, don't be afraid add more oil to your pad.

Now, you polish. As the shellac dries, you'll see a blur behind the pad as you polish. This "comet tail" is created by the alcohol and shellac drying. As the tail gets shorter and disappears faster, polish harder, eventually putting good pressure on the pad. This compacts the shellac, making it hard. At this point, I'm working about 1/6 to 1/4 of the guitar back. I work in circles, figure 8's, back and forth, but I always finish by going straight, along the grain. At first those swirls and boogers don't seem to go away. But, as you work it, you'll start to notice that they're slowly diminishing. Add more shellac and alcohol as needed. I also read the reflection. You'll start to see things come into focus. My favorite way of judging the shine, is by looking at the reflection of my shop lights. I have LED shoplights and I want to see the individual LEDs.

Keep doing this, using the same ratio of shellac/alcohol, until you feel that once again, you're moving rather than depositing the shellac. When this happens, add 1 more drop of alcohol to your pad with the shellac; so, if you were adding 2 drops, now add 3. If you added 4 drops, add 5, and so on. Eventually, you won't need as much shellac on your pad, and you'll be adding more alcohol than shellac. In the end, you'll just be adding the "dirty" alcohol to your pad, and no shellac.

This happens over a few days.

At this point, I don't do more than 2 sessions per day, because it seems to overwork the shellac, undoing my efforts. It may be necessary to reduce the sessions to 1 per day. It takes me about a week to spirit off.

Here are photos from the first spiriting off session on the Chechen.

There is no rushing french polishing. It takes as long as it takes...

I'm starting to spirit off the Chechen build. Hopefully you'll see the swirls in the photo, then see how it's diminished after 1 spiriting off session. Look at the reflection of the light fixture too. You'll see it starting to come into focus.

I'll update this as I work the guitar. Let me know if you have questions. Hopefully, I've not confused anyone.

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 Post subject: Re: French Polishing
PostPosted: Mon Apr 06, 2020 1:48 pm 
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Joined: Sun Mar 09, 2014 8:13 pm
Posts: 2248
Day 2 of spiriting off. I'm using 1/2 shellac with an equal amount of alcohol now. There's a little orange peel from overworking it. The alcohol is taking it out.

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 Post subject: Re: French Polishing
PostPosted: Tue Apr 07, 2020 9:54 am 
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Joined: Sun Mar 09, 2014 8:13 pm
Posts: 2248
I thought I'd picture my setup. The big jar contains a 2 pound cut of blond shellac. You can see the "dirty" alcohol (ie. alcohol with a small amount of shellac), the bottle of mineral oil, and jar with pad.

When I use the pad, I add a squirt of alcohol or shellac to the jar to store the pad, to keep it moist.

If I have to add more alcohol, I add a little shellac. Never use plain alcohol.
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 Post subject: Re: French Polishing
PostPosted: Tue Apr 28, 2020 10:04 pm 
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Joined: Thu Feb 21, 2019 10:51 am
Posts: 142
Location: Fishers, IN
Thanks for posting this - I seem to be drawn like moth to a flame to French polishing, I know I shouldn't but have a feeling its futile to resist.....

So clearly you're doing this prior to the neck going on - I'd love to hear your sequence of finishing and assembly.

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 Post subject: Re: French Polishing
PostPosted: Wed Apr 29, 2020 8:32 am 
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Joined: Sun Mar 09, 2014 8:13 pm
Posts: 2248
Morecowbell wrote:
Thanks for posting this - I seem to be drawn like moth to a flame to French polishing, I know I shouldn't but have a feeling its futile to resist.....

So clearly you're doing this prior to the neck going on - I'd love to hear your sequence of finishing and assembly.


I do all finishing before the neck goes on. I've found it difficult to finish around joints. You'll find when I do the top that the bridge isn't glued either. I clean the shellac from the area under the bridge and from under the fretboard extension prior to gluing. I DO NOT clean the area under the cheeks of the neck, on the shoulders, although I put glue in this area. The purpose of the glue in this area isn't structural; it's filler and it'sjust a very small amount. The load is carried in the joint. I want the finish to extend under the neck cheeks for continuity. I want the joint to disappear as much as possible.

I fit the neck and box to the point where it's ready to glue. I prefer to glue the fretboard to the neck, before fitting the neck. Therefore, I'm fitting them as a unit. When the fretboard/neck are ready to glue to the box, I finish the neck and box separately. When both are finished, I glue the neck. Then I glue the bridge.

I'll add to my blog on this guitar, outlining my sequence of assembly as I do it.

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 Post subject: Re: French Polishing
PostPosted: Wed Apr 29, 2020 8:51 pm 
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Joined: Wed Aug 13, 2014 12:14 pm
Posts: 1320
Yes -- finish the body and neck separately to keep them from being glued together by the finish . Makes neck removal for the eventual neck reset easier.

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