Shellacking pallet stones is a process used by watchmakers to ensure the stones remain secure and stable within the watch’s mechanism. This process involves using shellac, which is a type of resin made from lac insects, to create a strong bond between the stone and pallet. By understanding how to correctly apply shellac, you can make sure your watch runs accurately and smoothly for years to come.

Watchmaking is an art form that requires a great deal of precision. Pallet stones are essential components in regulating the movement of watches and must be set properly for optimal performance.

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Fortunately, pallet stone adjusting is one of the more complex repairs that doesn’t require a big investment in tools and supplies. What it does require is knowledge, which can easily be learned in this video series.

Here are a few things you’ll need to know before adjusting any stones.

The first question is whether to melt the existing shellac or apply new, and the answer is, it depends. It may be enough to simply heat the pallet and adjust the shellac if the shellac is in good condition and you are pushing in the stone to make the adjustment. 

The shellac will often cover the end of the stone in the slot, so you will end up damaging it. For this reason, I usually recommend removing the stone, cleaning up the pallet, and then re-shellacking it after you have adjusted it correctly.

Cleaning the Pallets and Stones

If you are re-adjusting both pallet stones you can just remove the bulk by just soaking the whole pallet fork in Denatured Alcohol. IPA will work but I find denatured alcohol is a little bit more aggressive when you want to remove all the shellac quickly.

If you are only adjusting one stone, obviously you don’t want to soak the whole pallet fork.

What I like to do is heat my Hairspring needling tool to scrape off the bulk of the shellac. I just made this one with a sewing needle which is mounted in peg wood. I heated the tip to bend it over and then filed it down to 0.02 mm and then polished it.

Using hot needle to remove shellac
Using hot needle to remove shellac

When you heat the tip you will see it go cherry red in about 5 seconds and you can use it to scrape off the shellac on and around the stone.

Once most of the shellac is removed, I put a drop of IPA on the area and then gently maneuver the stone to get it out of the slot. Be very careful because too much force will chip the stone.

Then you can clean up the rest of the area by going back and forth with a Nail Tee dipped in denatured alcohol or IPA and the hot needle. I use a balance screw pin vise to hold the pallet while I’m cleaning it but you can also just lay it on a bench block with the pivot in a small hole.

Cleaning Pallet wit IPA
Cleaning Pallet wit IPA

The pallet stone itself can be soaked in alcohol, then scrubbed clean with thin peg wood or a Nail Tee with alcohol. 

To handle the stone, I find it easiest to use just two sets of fine tweezers to turn it over while detailing each side. You want them cleaned from the old shellac but this is not the final cleaning. That will be done after the stone has been shellacked.

Holding tools

You will need a pallet warmer to secure the pallet fork when you are heating it.

Here are 3 examples.

The first is made of brass and may be the most common style you will find on eBay. You’ll notice that the warmer is split. That’s to allow one side of the pallet to get hot enough to melt the shellac without melting the shellac on the other pallet.

The pallet is held in place by this lever which goes on the opposite side of the pivot of the stone you are heating.

The problem with this style and others as well are that the hold down is not strong enough to hold the pallet when you push on the stone. What you can do is use two sharpened pieces of peg wood, one to prevent the stone from moving and one to push the stone. It works but it’s a little awkward.

Brass Pallet Warmer
Brass Pallet Warmer

The second one is just a variation of the brass holder. This warmer has a steel table but works in the same way. It does have less of a split so it doesn’t isolate the heat from the pallet as well, but that’s not really a problem as it cools down pretty fast, locking the unmoved stone in its place again.

Pallet warmer with steel table
Pallet warmer with steel table

The third type is what I go to when I need to adjust stones. It has an aluminum body which is ok, but the biggest difference is that it locks the pallet fork in place. Not only does it lock but the two pivoting arms are angles to fit flat over the impulse plane, so as soon as it comes off the heat you can make the adjustment.

Aluminum pallet warmer with indexing arms
Aluminum pallet warmer with indexing arms

It does have a graduated scale but I find it pretty much useless under the microscope, but I’ll come back to that in a few minutes.

Heating shellac

There are a couple of different methods to apply shellac to the pallets so I am going to show you a couple of different ways so that you can try both to determine which method works best for you. I like to use a combination of the two.

Applying Shellac to pallet stones Hot Method

Shellac has a melting point of 167 degrees or 75 celsius. The two biggest challenges with working with the shellac is its open working time before it hardens again, which is about 10 seconds, and the small amount that needs to be applied to the stone to hold it in place. If there is too much shellac, it can interfere with your divisions and drag on the main plate.

The first thing you will need to be able to do is to heat the shellac to the melting point. This can be done with a spirit lamp or by using a hot plate.

Spirit lamp for melting shellac
Spirit lamp for melting shellac

The advantage of the spirit lamp is the low cost of the lamp and fuel and the fact that it comes to temperature right away. The disadvantage is that if you use the wrong fuel, they can produce a lot of black soot which will need to be cleaned off the pallets once the shellac hardens. I have found that denatured alcohol burns pretty clean and with a 1-inch flame and there is almost no residue at all.

A good quality hot plate can produce a more controlled heat without the worry of black soot but it should have variable control and you will need to be able to measure the heat coming off its surface. The disadvantage is that a good one can be a lot more expensive and they take longer to heat up.

I’ll be using the spirit lamp today because it’s what I use and know best.

Preparing the shellac

The shellac you want to get is known as Dewaxed blond shellac flake and has a dark amber color to it. A four-ounce jar will last you a lifetime so there’s really no need to buy it in large quantities.

 To prepare the shellac, you can just hold a piece with your tweezers, heat it over the spirit lamp and when you see it just start to bubble, take another pair of tweezers and grab into the melted bubble and slowly pull away. If you go too fast, the string will be too thin. You are really aiming for a string about ½ the width of the jewel itself.

Pulling Shellac for pallet stones
Pulling Shellac for pallet stones

To apply the shellac to the cleaned stone and pallet, you can break off a small piece of the string and lay it on the top back end of the jewel, and then heat it for about 10 seconds or so on the lamp. The goal is for the shellac to flow out flat on the jewel, draping over the sides of the stone and filling in the gaps between the stone and pallet, locking it in place.

Appling a piece of shellac to pallet stone
Appling a piece of shellac to pallet stone

The shellac will be a little sticky so you can use a sharpened toothpick to move it around to get into position.

Looking at the shellac as it comes off the heat you can see that the upper part of the stone looks a little light, so I just move a little over to that side and reheat it for a couple of seconds so that it flows back out.

Shellac melted unevenly on pallet stone
Shellac melted unevenly on pallet stone

There, now we have good coverage that will hold the stone securely.

The 2nd way and the way I like to do it is kind of like soldering a copper pipe.

Appling shellac to pallet with string method
Appling shellac to pallet with string method

I leave the shellac thread on the tweezers, heat the pallet up to temperature and then just touch the string to the stone to deposit the shellac and then heat it up for another three or four seconds so that it flows out flat.

Once it’s cooled off, I can check the coverage and make sure it flowed out flat and now it can be cleaned and installed into the movement.

Applying Shellac to pallet stones Cold Method

The third way to shellac pallet stones is by dissolving the shellac in denatured alcohol. This jar has about 4 tablespoons of shellac flakes dissolved in denatured alcohol.

Dissolved shellac used for cold method
Dissolved shellac used for cold method

Oftentimes the pallet stone will be too loose to stay in the slot when making adjustments to it. I use the thin top layer inside the jar and apply it to the pallet slot to lock the stone in place while making adjustments.

Securing Pallet stone with liquid shellac
Securing Pallet stone with liquid shellac

 It dries really fast and holds the stone while you are checking your adjustments but melts fast when you need to move the stone in or out.

Once the adjustments are made then you just use an oiler to transfer the fresh liquid shellac to the stone. Once there is enough shellac on the stone, you just put it on the heat to allow it to flow out. This method gives you the most control over how much shellac is being used.

You can see that the shellac is still a little soft when I push down on it but I can put it back on the heat for a couple of seconds and it flows right back out.

Applied shellac by cold method
Applied shellac by cold method

This is the method that I like to use because I have more control.

In conclusion, there are multiple ways to apply shellac to pallet stones. The method you choose should depend on the situation and your own preferences. 

Spirit lamps can be used for melting waxes or working with metals but they also work great when applying shellac to pallets. Alternatively, dissolving the shellac in denatured alcohol is another effective way of controlling exactly how much shellac goes onto a stone while still getting good coverage over it. 

No matter which technique you decide to use, remember that practice makes perfect! With enough practice and patience, any jeweler will achieve beautiful results when using these methods for securing their jewels into place with Shellac.