The Birth of Aradia (part V)

The last four instalments in the saga of Aradia’s construction have formed a tale of scouring eBay for parts, avoiding any woodworking that required serious precision and carrying out the remainder of the woodworking with the most inadequate tools and laughable incompetence I could muster. Now, however, I have managed to shamble my way to having a functional bass guitar, and the time has come for the final stage of the process. What follows should hopefully serve as a crude guide to French Polishing a guitar.

The trouble with French Polishing is that nobody can quite agree on a way to do it. When my father and I first attempted it on Brenda, some eleven years prior to this project, we used a combination of pre-mixed shellac solution and linseed oil. When I discussed the process with Alex (who did the neck pocket adjustment described in Part I), he described a much more complicated process that involved filling the grain of the wood with powdered pumice.

At his recommendation, I read the French Polishing tutorial written by Milburn Guitars. This is definitely worth reading once for all the detail, but is a bit heavy-going to serve as an instructional guide (it’s more like a treatise on the whole philosophy of French Polishing), so I used a more concise guide written by a Mandolin luthier, referring back to the Milburn tutorial for any details that weren’t very clear.

In this version I will not be doing quite what they recommend, the key difference being that I used pre-mixed shellac. Both of the above guides are quite insistent on the superior quality offered by buying dried shellac flakes and dissolving them in alcohol; I realised it would be cheaper to buy a half-decent bottle of pre-mixed shellac solution, and I would only be doing the one job anyway. So, if you think you can still trust this as any sort of guide, you will need the following:

– Shellac
– Alcohol
– Oil
– Powdered pumice
– Sandpaper of various grits
– An old shirt or T-shirt
– Waste cotton is also helpful

Shellac forms the basis of a French Polished finish. The idea is to build up a number of layers of shellac over the surface of the wood, which give it a deep, rich shine. You’ll need to dilute the shellac to varying degrees with alcohol as you go; I found methylated spirit did the job just nicely.

The old shirt (and cotton waste if you can get it) is used to form the pad which you use to apply the shellac and alcohol. (Make sure you never intend to wear said shirt again, because you’ll be cutting it up into little squares to make these pads!) The oil is used in small quantities to stop the pad sticking when you’re applying shellac to the surface. I used raw linseed oil for this purpose.
A shirt like this, in fact...

Powdered pumice is probably the most expensive ingredient, but you do only need a small amount of the stuff. It’s used to fill the grain of the wood, so you have a flat surface on which to build up your finish.

Step 1 is to prepare the wood for finishing and apply a spit coat. I went at the wood with 60 and then 80-grit sandpaper; a lot of guides recommend working up to several-hundred-grit before you start polishing, but I only had those two and was impatient to get started.
Spit coat (front)
With the sanding done, I cut a square out of a very old shirt that the missus had already strongly recommended I stop wearing. This square was a little smaller than an A5 page and was folded a couple of times. Loading it with a generous amount of shellac, I wiped it in straight lines across the back of Aradia’s body and neck. A second and third coat were applied in the same way, leaving a good half-hour in between for the coats to dry.

The process was then repeated on the front of the body and headstock. (NB no shellac was applied to the fretboard: this was rosewood, which I had decided not to apply any permanent finish to.)

A few days later, I got started on Step 2: grain-filling. (I would have started sooner, but for rehearsals and stuff. And the continuing nuisance of having to go to work.) The grain-filling is done using the pumice, and you’ll also need to make your first pad.

For this pad, I took another square(ish) lump off the shirt – a bit smaller this time – and put a ball of cotton waste in the middle. I pulled up the sides of the shirt so I had a flattish pad shape where the ball was, and tied up the top with an elastic band.

Sprinkling a tiny amount of pumice onto a piece of paper, I dabbed the pad on the paper to pick up a smaller amount and spread it around the surface of the pad with a fingertip. Alcohol was then added to the pad, and the pumice rubbed into it. This is the key bit: the alcohol renders the pumice transparent, so specks of it (hopefully) won’t show up in the grain of the wood.
After pumicing
Once loaded, the pad is rubbed on the spit-coated wood in a tight, circular motion. You should end up with a much more matte finish where your spit coat had previously left the wood looking nice and shiny.

I was worried about taking off all of the spit coat with the pumice – in hindsight, I needn’t have worried. The whole point of rubbing the coated wood with pumice is to chew up the shellac and work it into the grain of the wood, closing the pores.

It seems one of the important aspects of French Polishing is being patient, but in spite of this I started on Step 3 the same evening: bodying.
Bodying (2nd coat)
The guide I was using recommended a 2 lb cut of shellac, adding 10-12 drops of shellac and 6-8 drops of alcohol to the pad. Because I was using a pre-mixed shellac solution, I had no idea what the concentration was, but 12 drops of shellac and 6 drops of alcohol sounded close enough, to me, like “2 parts shellac to 1 part alcohol.”

I also hadn’t done the other thing most guides recommend, which is to put your shellac and alcohol into small squeezy bottles, in order that you can add them to the pad dropwise. I decided, instead, to mix them in an old plastic tub. And instead of measuring by drop, I was measuring them out by the teaspoon.

So: two teaspoons of shellac solution, one teaspoon of alcohol and a few drops of linseed oil. The oil is important to stop the pad sticking to the wood and/or previous coats of shellac. It’s best not to use too much, but any excess is removed later on in the ‘stiffing’ and ‘clearing’ stages.

Dipping the pad into my shellac/alcohol/oil mixture, the mixture was wiped onto the body in small circles, working gradually over the back of the body and neck. One trick is not to return to areas that have already been covered – the shellac dries quickly and the pad will start to stick and possibly remove the partly-set shellac.

Just to contradict that warning, once the back face was covered, I then returned to where I’d started and wiped more shellac onto the wood, this time making straight passes along the length of the guitar. Once the back face had been covered in this way, the shellac was left to dry. After leaving it for a minimum of half an hour, but usually more like 45 minutes, I went back and applied another coat in the same way. After I’d put three coats on, I turned Aradia over and did the same to the front.

It sounds a bit laborious, but the whole process is actually strangely relaxing. Once you’ve done a couple of coats and have got the hang of the procedure, it becomes quite easy to time things. Putting a coat on one face of Aradia would take 10-15 minutes, and then I could go and do something else for 45 minutes or so while that coat dried.

The guide I was using recommended doing this between four and eight times to build up a thick coat of shellac, and I decided to go for eight. That is to say, eight sessions, applying three coats in each session, so a total of twenty-four coats.
7th bodying session - 21 coats
Step 4: In between these sessions, it is recommended that you “stiff” or “clear” the finish. Stiffing and clearing are intended to remove any excess oil from the finish, and the only difference between them seems to be what type of pad you use. In both cases, a pad is loaded with alcohol, which is rubbed firmly along the surface of the wood in straight lines.

Stiffing is done shortly after the final coat of the bodying session is finished – again, I left about 45 minutes for the coat to dry – and uses the same pad you used to apply the shellac. Clearing is done after much longer – usually overnight – and uses a clean, folded cloth with only alcohol added to it. Personally, I found that as long as I wasn’t using too much oil when bodying, it was only necessary to perform one of the two.

Step 5 may not be necessary, depending on how dilute your shellac/alcohol balance has been, and how well you’ve applied it. This step is known as rough levelling and is the process of using very fine sandpaper to smooth out any imperfections in the finish. Using a clean cloth, a light coat of oil is wiped onto the wood, and 400-grit sandpaper is rubbed on any rough areas in a circular motion.

From my experience, I would advise caution with this step. It’s very easy to “burn through” the shellac you’ve already applied, and I certainly found that the relatively flat surface of the mahogany body had few lumps and bumps that needed removing. After working a bit on the back, I realised all I was doing was sanding off the finish I’d worked so hard to apply! It did, however, prove useful on the neck and headstock, where the more detailed contours had been harder to apply the shellac to smoothly. After 8 sessions, pre-sanding

The sanding removes some of the gloss...

...but thankfully it soon goes back on

On the plus side, if you do go too far with the sanding, there are plenty more bodying sessions yet to come in which you can restore that beautifully layered coat of shellac.

As this post appears to be getting a bit on the long side, I shall break here and detail the last of the process in part VI. At the time of writing, I’ve finished the rough levelling and completed another bodying session over the top of that. Things are looking promising. Hopefully, the next instalment will detail the completion of the process, and Aradia will look beautiful and shiny. Hopefully.

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