A Hands- on Tutorial by |
Orville and Robert Milburn
재 료
French polishing에 쓰이는 도구와 재료는 매우 적고 간단하다. 사실 몇 달러만 투자하면 당신도 많은 장비(악기)에 쓸 만큼을 얻을 수 있다. 이 글 끝에 필요한 재료들을 구입할 수 있는 곳의 목록을 달아두겠다.
쉘락
락은 락 딱정벌레라고도 하는 '코쿠스 랔카'라는 곤충에 의해서 모아지는 자연물질이다. 이 물질은 곤충의 집 역할을 하는 많은 종류의 나무에서 모아진다. 락(Lac)은 나무의 가지와 껍질에서 얻어진다. 수확된 락은 정제되고 따뜻한 락 주머니에 싸인 수공의 형태(쉘락)를 포함해 수많은 형태로 가공된다.
Shellac flake on left and ground shellac on right. The shellac flakes were ground using a coffee grinder. Shellac is non-poisonous and is approved for use in food by the FDA. |
수확된 락의 주머니는 열에 의해 가열된다. 락이 녹으면 락 주머니를 락이 주머니 바깥쪽으로 새어 나올 만큼의 충분한 압력으로 교압기를 이용해 짠다. 락의 많은 양은 쉽게 저장하기 위해 바삭바삭한 조각으로 부숴지기 쉬운 얇은 판으로 가공된다. 쉘락은 대개 공업에 쓰이는데 페인트가게나 기자재점에서 살 수 있는 일부는 쉽게 사용할 수 있도록 가공되어있다. 쉘락 조각의 상당부분은 고급 수제품 전문 마무리공들에게 들어간다. 시간이 흐르면서 '쉘 락'은 '쉘락'으로 불리게 되었다. 쉘락이 수확되고 가공되는 과정에 대한 가장 좋은 설명서는 "American Lutherie No. 54, summer 1998."이다. 이것은 미국 최고의 Luthier이며 French polisher 중 한 명인 Cyndy Burton이 쓴 것이다. 우리가 쓸 쉘락은 조각으로 팔고 있는 것이다. 쉘락 조각은 적어도 네 가지가 될 수 있다. 쉘락의 타입은 색깔을 표시하는데 밝은 것부터, white, blonde, orange, dark(garnet)이라고 부른다. 일단 쉘락을 필요한 만큼만 알콜에 녹인다. 용해된 쉘락은 유효지속시간(shelf-life)이 짧기 때문이다. 쉘락과 알콜 혼합물은 시간이 지나면 습기를 흡수하면서 가수분해되어 질이 떨어진다. 수개월 내에 사용할 만큼만 섞는 것이 바람직하다. French polishing에는 가게에서 파는 기혼합 쉘락이나 캔에 담긴 것을 사용하면 안 된다. 기혼합 쉘락에는 유효지속시간을 늘리고, 유동성을 높이고 브러쉬를 사용할 수 있게 만들기 위해 건조를 지연시키는 첨가물이 많이 들어있다. 믿을 만한 가게에서 양질의 쉘락 조각을 사기 바란다. 이 글 끝에 쉘락 조각을 살 수 있는 곳의 이름과 주소를 적어 두겠다.
알콜
알콜을 많이 사용하게 될 것이다. 알콜은 쉘락 조각을 녹이는 데, 희석하는 데, 공극을 메꾸는 데, 그리고 French polishing의 다른 과정에도 쓰일 것이다. 양질의 기자재점에서 파는 알콜이면 충분하다. 하지만 일부 사람들은 변성과정에서 알콜에 첨가된 물질에 예민하다. 변성알콜은 메탄올이 약간 들어간 에탄올이다. 무엇보다도, 변성알콜은 어린이의 손이 닿지 않는 안전한 곳에 닫아두어야 한다. 사려깊은 사람이라면 알콜 취급점-또는 주류점-에서 순수한 알콜을 살 것이다. 이렇게 하면 많은 돈이 들긴 하지만 순수한 에탄올을 구할 수 있다. 변성알콜의 증발하는 정도가 좀 문제가 될 수 있다. 알콜의 라벨을 잘 보고 메탄올만으로 변성작업 된 에탄올을 구입해야 한다. 다시 말하지만, 필요한 만큼만 섞어야 한다. 알콜은 열어두면 증발하면서 수분을 흡수하게 되므로 순도를 유지하기 위해 병의 뚜껑을 닫아 두어야 한다.
속돌(Pumice)
Pumice는 갈고 pore filling하고 연마하는 데 쓰인다. Pumice는 다른 마무리작업에서 광택재로 쓰이기도 하며 특수도장재상점에서 구할 수 있다. 여기서는 아주 좋은 FFFF등급의 속돌을 쓴다. 처음에는 pore filling과 Pumice를 사용하는 것이 어려울 수 있지만 익히고 나면 작업이 쉽게 진행될 것이다.
These are the main materials used for French-polishing. The containers are chosen to aid in dispensing proper amounts of the various materials. |
기름
올리브유는 French Polish를 할 때 윤활유로 쓰인다. 쉘락에는 뮤네카(정확히 뭔지는 모르겠습니다만 후반부에 만드는 법이 나옵니다)나 접은 패드(부드러운 소재의 두툼한 조각을 pad라고 하는데 이것도 그림 참조하시기 바랍니다)만 사용해야 한다. 뮤네카는 쉘락이 제대로 퍼지게 하기 위해 나무 표면에 잘 눌려야 한다. 이렇게 잘 누르는 것은 각각의 미세한 쉘락 층이 기존의 쉘락 층과 융합되어 풍부하고 깊은 칠을 만드는 작업이기도 한데, 쉬운 작업이 아니다. 기름을 현명하게 사용하면 뮤네카가 붙거나 끌리는 일 없이 나무에 강하게 누를 있다. 쉘락이 표면에 앉으면서 기름은 칠을 통과해 위로 올라오려고 한다. 따라서 칠의 아래 갇혀 칠을 망치지 않는 기름을 사용하는 것이 중요하다. 순도 100%의 올리브유(100% virgin olive oil)를 쓰는 것이 바람직하다. 왈넛오일(호두기름)이나 베이비오일, 파라핀 오일 등은 산화방지제나 향신료 같은 불순물이 포함되어 도장에 문제를 일으킬 수 있다. 따라서 초보자는 우선 순수한 올리브유를 사용해야 한다.
연마용구
French polishing을 위한 세부사항과 기타(guitar)의 준비사항도 도장 그 자체만큼 중요하게 다루겠다. 모든 등급과 형태의 연마도구 목록이다;
- 220 grit open-coat dry sandpaper 3M "Gold" 216U
- 320 grit open-coat dry sandpaper 3M "Gold" 216U
- 400 grit wet/dry automotive sandpaper 3M "Imperial 401Q
- 800 grit wet/dry automotive sandpaper 3M "Imperial" 401Q
- 1200 grit wet/dry automotive sandpaper 3M "Imperial" 401Q
- Micro-Mesh "Cushioned abrasive" 3200
- Micro-Mesh "Cushioned abrasive" 3600
위의 연마도구가 당신이 처음으로 French polishing을 완성하는 데 필요한 전부이다.
Here are some of the sanding blocks we use in leveling the finish. In the back is a large wooden block with a cork pad. Next to it is a mahogany block with a round edge to smooth the inner surface of the string slots. Also shown are various rubber blocks. Some are made of pink pencil erasers. Note the various sizes and shapes. |
천
일단 모직물이나 수술용 거즈를 내부재로, 티셔츠 재료와 같은 100% 면직물을 외부재로 하여 문지르개 또는 뮤네카(헝겊인형의 스페인 말)를 만든다. 울이나 거즈를 쓰는 것은 뮤네카 안의 쉘락이 손이 누름에 따라 바깥으로 빠져 나가는 것을 막기 위해서다. 깨끗한 면 거즈나 순수한 모직물을 내부재로 쓰지 않는다면 쉘락은 제대로 퍼지지 않을 것이다. 인조직물이나 인조 합성물은 뮤네카에 절대 쓰면 안 된다. 낡은 티셔츠는 외부재에 적합하고 모직양말 조각은 내부재에 적합하다. 부드러운, 닦아낼 천(wiping clothes)도 많이 준비해 둬야 한다. 직물점에서 한 야드쯤 되는 티셔츠 소재를 좀 나으면 두어 벌의 낡은 티셔츠를 준비하고 싶을지도 모르겠지만 그렇게 많은 양은 필요 없다. 기타와 닿는 것들은 전부 불순물이나 먼지가 없는지 확인해야 한다. 아주 작은 먼지 입자도 도장에 눈에 띌 만한 상처를 낼 수 있다. 도장은 굳기 전엔 아주 약하다.
세정및 광택제
전에 말했듯이, French polishing에는 광택재가 전혀 쓰이지 않는다. 그러나 도장을 끝내고 나서 남은 기름 찌꺼기를 제거하고 지문을 없애기 위해 악기를 닦을 필요가 있다. 이를 위해서 ‘Meguiar’s No.7 Show Car Glaze’를 사용한다. Meguiar’s #7은 연마제가 들어있지 않으므로 지속적으로 반복해서 써도 안전하다. 좀 더 강한 광택재가 필요하다면 ‘Meguiar’s #9 Swirl Remover’를 쓰면 된다. #9은 고급의 연마제가 들어있어 도장을 일부 제거할 것이다. 미세한 상처들을 제거하기 위해 사용하기에 알맞지만 지속적으로 쓸 수는 없다. 이들은 도장이나 나무에 상처를 낼 수 있는 실리콘 성분이 전혀 첨가되지 않은 양질의 상품들이다. 자동차 부품점이나 자동차 도색점에 가면 구할 수 있다.
기타
- . 폭 1”, 길이 5/4, ?인치 두께의 갈아낼 조각(rubber sanding block). 정확히 사각형인 나무조각에 아래쪽에 코르크가 붙어있으면 충분하다. 대개의 페인트 가게에 가면 작게 자를 수 있는 ‘갈아낼 조각’을 판다. 다른 데서도 비슷한 것들을 구할 수 있을 것이다. 코르크를 붙일 때는 에폭시를 이용해서 붙여야 한다. 다른 접착제는 기름과 용매에 의해서 떨어질 수 있다.
- 압착할 때 쓸 작은 병도 쉘락과 알코올을 퍼뜨리기 위해 중요하다. 작은 풀통 정도면 적당하다. 최소한 두 개는 준비해야 한다.
- 뮤네카와 문지른 천들이 마르지 않게 저장할 밀폐용기가 있으면 좋다.
- pumice를 퍼뜨릴 소금통 하나(salt shaker)
- 기름을 퍼뜨릴 약통 하나(medicine dropper bottle)
- 나프타 용매 1.14리터 정도(a quart)
- 기타 넥 지지대. French polishing을 하는 동안 기타는 넥으로 지지되어야 할 경우가 많다.
- 강력접착제와 5분에폭시(SuperGlue and 5-minute epoxy)
- 스탑워치
- 작은 깔대기
- 타이핑 페이퍼
끝으로, 작업할 공간이 필요하다. 당신은 작고 밝은 곳이나 집에 남는 방을 작업실로 쓰려고 할지 모르겠다. 온도가 적당하고 먼지가 없는 곳이 적절하다. 먼지를 좀 적은 구석이 좋을 것이다(공기중의 먼지는 작업 후반에 고려한다). 이제 French polishing에 필요한 것들을 전부 살펴봤다. 자 에제 시작합시다 …
기타 손질하기
모든 피니시(도장)의 질은 그 악기가 어떻게 손질되었는가에 크게 영향을 받는다. 좋은 도장을 사용할수록 결점(악기의 흠 같은 것)은 더 뚜렷이 드러날 수 있다. 지금은 목재 다루는 법은 깊이 다루지 않고 기타가 잘 마무리되어 있고 사포작업도 잘 되어 있으며 각 틈이 제대로 메꿔져 있다고 간주하겠다. 가장자리 장식과 바인딩은 완전히 평면을 이루고 있어야 한다.
Detailing the guitar edges with a sanding "stick". |
Using cyanoacrylate adhesive (SuperGlue) to fill small defects in the rosette. |
쉘락 녹이기
우리의 쉘락을 준비할 시간이다. 다음 단계에서는 알코올과 쉘락 조각의 적당한 ‘컷’이 필요하기 때문에 적절한 컷을 얻기 위한 알코올과 쉘락의 혼합 비율을 알아야 한다. 1파운드 컷은 1파운드의 쉘락 조각을 1갤런의 알코올에 녹인 것을 의미한다. 만약 2파운드 컷(두껍거나 무거운)을 원한다면 쉘락 조각 2파운드를 알코올 1갤런에 넣는다. 전에 말했듯이 단기간에 쓸 수 없을 만큼 많은 양을 혼합하는 것은 안 좋다. 게다가 2파운드 컷 1파인트면 기타 하나를 완성하는 데 충분한 양이다. 적당한 양으로 만들기 위해서 쉘락과 알코올의 양을 비율에 맞게 나누어보자. 1파운드 컷은 쉘락 조각 16온스를 알코올 128온스에 녹인 것이다. 이것은 1온스의 쉘락 조각이 8온스의 알코올에 녹은 것과 같다. 따라서 적절한 2파운드 컷의 양은 쉘락 조각 2온스를 알코올 8온스에 녹여 만들 수 있다. 여기서 최종 혼합물을 결정적으로 망칠 정도가 아니라면 비율의 정확성에 지나치게 신경 쓸 필요는 없다.
Various shellac solutions. From far right: Very thin cut of "luna" shellac, 2-pound cut of "luna", 2-pound cut of garnet shellac, olive oil for comparison. |
쉘락 조각을 알코올과 섞은 다음 완전히 용해되도록 24시간 동안 둔다. 쉘락 조각을 커피 믹서(분쇄기)에 넣고 갈아서 고운 가루로 만들어 사용하면 금방 쓸 수 있다. 가루는 조각보다 몇 배나 빨리 녹을 것이다. 어느 정도의 진동이나 적절한 열도 이 과정에 필요한 시간을 단축시킬 수 있다. 혼합물은 물중탕으로 가열하며 열판이나 레인지는 사용하지 않는다. 이렇게 하면 몇 시간 만에 용액을 준비할 수 있다. 용해됐으면 쉘락을 짜낼 용기에 옮겨담는다.
주의사항
- 작업실에서는 담배를 피우지 않는다.
- 난로 등의 직접적인 불이 있는 방에서 작업하지 않는다.
- 통풍이 적당히 되는 공간에서 작업한다.
- 쉘락과 알코올을 어린이가 만질 수 없는 곳에 보관한다.
단위 :
1 ounce = 30 grams
1 gallon = 128 ounces or 3840 grams
1 gallon = 8 pints
1 pint = 16 ounces or 480 grams
기타 실코팅(seal-coating)하기
이제 French polish를 위한 기초작업을 할 준비가 됐다. 이 기초작업은 ‘spit-coat’, ‘wash-coat’, ‘seal-coat’라고 부르는 작업이다. 목적은 세 가지이다. 기타에 칠할 쉘락 미세층에 점성 있는 표면을 제공한다. 쉘락은 점성이 강해서 세계 최고의 우드 실러(wood-sealer)로 알려져 있다. 둘 째, 백과 사이드의 기름과 염료에 의해 상감장식, 가장자리 장식, 로제트 등이 더러워지는 것을 막아준다. 세째 Pumice와 목재염료가 나무의 공극에 잘 섞여 들어가게 해 준다.
Sealing the edges of the back of a rosewood guitar. You can easily see the seal coat left by the wet pad. |
Sealing the edges of an instrument. Note the "field" is already sealed. Here we are sealing the purflings and bindings a second time. |
An example of a folded pad after it has been used to seal a section of a guitar edge. This coloration will contaminate white purflings and light wood. |
Removing purfling contamination using a small scraper made from a heavy single-edge razor blade |
Filling the grain and pores
Pumice is of volcanic origin and has been around for hundreds of years and used for a variety of purposes. Before modern technology developed the fine sandpapers that are common in the marketplace today, pumice along with many other materials were used as abrasives. The wood finisher used a felt block and often a leather-covered block with pumice powder to sand the wood smooth. Pumice was also used to polish shellac and resins to fine high-gloss finishes. The pumice for the wood finisher was ground and filtered into many different grades and sizes much the same way as we buy different grades of sandpaper today. No doubt, at some time during sanding, it was discovered that the pumice not only acted as an abrasive but filled the wood grain at the same time. The pumice method of grain filling has been with us for hundreds of years and is still the preferred method of grain filling for many wood finishers.
Lets start our grain filling now . . .
After sealing the instrument is allowed to "gas out" (remaining alcohol is allowed to evaporate) for a few hours. We are then ready to fill the pores and grain. This is the pumicing operation. At this point we should mention that there are some species of wood that do not require grain and pore filling. The top of the guitar will not have to be grain filled. Spruce, Cedar, and Maple are examples of "closed-pore" woods which do not have to be grain filled, and with some experience you will recognize woods which require grain filling and those that do not. Most rosewoods have large, open pores and will need to be filled. If the pores of an open-pored wood are not filled properly the finish will slowly shrink back into the pores. The result will be thousands of tiny craters in your finish.
Applying the Pumice
We will not be using any new shellac during the entire pumicing process. This is very important- additional shellac during the pore-filling process will inhibit the operation. We will be using the already dry shellac "spit coats" that we have previously applied to the guitar. All that is used is the muneca loaded with alcohol and a very small amount of pumice applied to the muneca surface.
The muneca is touched to a bit of pumice on paper. The pumice is then distributed over the surface of the muneca with a finger. |
The actual pumicing procedure is simple and is as follows . . .
Add a generous amount of alcohol to the surface of the muneca. Be careful not to overdo the alcohol (about 10 to 12 drops is what we call generous). You will always have to add extra alcohol to a dry muneca. Once wet, however, just a few drops(4 or 5 for each recharge will be enough). Note that we will always load the muneca from the outside. Tap the muneca against the back of your hand to help distribute the alcohol throughout the wool pad. Fill your salt shaker with pumice and sprinkle a small amount onto a sheet of typing paper. Now, use the bottom edge of the muneca to "bite" off a small portion of the pumice. With the pumice sticking to the bottom of the muneca, add a few drops of alcohol (4 to 5) and rub with your finger until the pumice becomes transparent. This "clears" the pumice. NEVER APPLY PUMICE DIRECTLY TO THE SURFACE OF THE INSTRUMENT. Beware of clever gimmicks such as powder puffs and "pounce bags" used to add pumice directly to the surface of the instrument. They are unnecessary and silly.
The pumice is made transparent by wetting it with a few drops of alcohol. |
The grain is filled by moving the pumice-loaded muneca in small circular motions. Direction should be changed often. The grain is best filled when the muneca is moved against the grain direction. Don't move the muncea in long strokes parallel to the grain. |
REVIEW
Now lets review the grain filling procedure . . .
- First, "seal-coat" or "wash-coat" all of the purflings with 3 sessions of shellac, being careful to protect the inlay work from color contamination. Seal the "field" areas similarly.
- While spit coating, fold your shellac cloth often to avoid discoloring the inlay work. Pull the cloth in one direction with a single motion. After spit coating the guitar three times, you can then paint more shellac on the purflings using a soft camel hair painter's brush. Do this if you are having contamination problems.
- Use no shellac or oil during the grain filling process. The spit coats of shellac with the alcohol, combined with pumice, will be all that is necessary to fill the grain.
- Remember to "clear" the pumice. Dab the wet muneca on a little sprinkle of pumice. Add additional alcohol and rub the pumice evenly on the bottom of the muneca to clear the pumice.
- Always load the muneca from the outside with alcohol. Be careful to not add too much alcohol. 10 to 12 drops to a dry muneca and 4 to 5 thereafter should be all that is necessary.
- Using firm pressure, rub the muneca onto the surface using circular motions and change directions often.
- Grain fill only small sections of the guitar at a time. Any excess pumice can be moved to an unfinished area using a little alcohol.
- Inspect your work often and use very little pumice as you work. Do not get impatient and try to hurry. This may result in more work in the long run. A bright lamp at a low angle will help visualize unfilled pores.
Making the muneca
Lets start our project by first making our muneca. There are a number of ways that a muneca can be made but to simplify the task we will explain several ways that we make ours.
A muneca cover made of several layers of wool. |
First, cut three round disks out of a thick wool sock or sweater. Be sure that it is 100% wool. If it contains any synthetics it may not dispense the shellac properly. The first disk should be about 1 & 1/4" in diameter.The second one should be 3/4" in diameter and the third about 1/2" in diameter. Now, stack all three together starting with the largest going down to the smallest. With a needle and thread sew the edge of the large disk to the top of the small disk. Do not pull the edges tight. Sew them just enough to keep them together. Next, cut a 4" x 4" square of t-shirt material and lay it flat on the table. Lay the stack of wool with the large flat side in the middle of the square.
A muneca core made of 18 inches of cotton gauze. |
Grasp the four corners of the t-shirt material and twist all four corners until the encapsulated wad of wool lays firmly between the thumb, index, and forefinger. Another way to make the muneca is to cut a small wad of wool from a wool sock or sweater about 3" x 3" square. Form into tightly in the muneca cover as we did before. Attach a rubber band around the base of the core and really flood it with some 2-pound cut shellac. Let the muneca sit in the open air for several hours. Once most of the alcohol evaporates the core will retain its shape. Cotton is an alternative to using wool for the muneca core. Surgical gauze (from a pharmacy) makes a good core. Cut about 18 inches of gauze and begin by
Before using the muneca, twist it tightly to make it harder. |
folding one end over and over again. Rotate the folded portion after each wrap while attempting to make the core as tight as possible. Ideally, you would like to make a finished core that has a somewhat rounded bottom and about one-half as high as it is in diameter. Once the gauze has been wrapped into the shape and size you want, wrap a cover around it and hold it in place tightly with a rubber band. Flood it with shellac and let it evaporate as in the above example. In both these examples you will probably want to make new covers rather than use the covers with the dried shellac as they will take quite some time to soften. Always put your munecas into a sealed container when you are not using them. Add a few drops of alcohol to the container. This will help prevent the muneca from getting hard. Also take care to change the muneca cover whenever it becomes damaged (often when you use pumice) or stained.
BODY SESSIONS
Assuming that the pumicing and grain filling went well and has been completed, we now begin our French polishing "sessions". We use the term sessions rather than "coats" such as a furniture finisher would use. We will be applying literally hundreds of microscopic layers of shellac to the instrument resulting in one single amalgamated layer of shellac. As you can see, in the case of French polishing, the term "coats" does not apply. During each session we will apply dozens of layers of shellac and will complete as many sessions as it takes to "body" the guitar (which is usually 6 to 8). Before proceeding, you may wish to examine the entire guitar very closely for any defects or unfilled grain that may have been overlooked previously. A little pumice and alcohol will take care of the unfilled grain. Remember, it is never too late to pumice. If the defects can be taken care of by a light sanding, use only 400 grit wet and dry sandpaper with oil as a lubricant. At this stage of finishing, in areas where there are "sink-outs", nicks and dents will tend to show where they previously were not apparent. This is the time to take care of and remedy any trouble spots that are visible. Any sink-outs, pin holes, or nicks can be filled using SuperGlue. First clean the area with naphtha, apply the glue and sand with 400 grit wet or dry sandpaper using oil as a lubricant. Now remove any excess pumice that may be left on the surfaces of the guitar using alcohol and a new muneca cover. The new muneca cover, along with alcohol, will tend to collect excess pumice. Now that we're satisfied with our inspection, lets begin "bodying" the guitar with shellac.
BODYING
Bodying is the process of applying shellac in many thin applications until a sufficient thickness is achieved. The body is sufficient when it can be sanded level with very fine sandpaper without burning-through to wood. Hundreds of passes of the muneca will be required, though individual layers are not the result. All the passes merge into one amorphous "sheet". Downward pressure of the muneca is critical for achieving a good degree of hardness of the final finish. We will be using a full 2-pound cut for the first 6 to 8 (body) sessions. Since we will not be too concerned about how smooth the body sessions go on, our efforts will be to build up the base finish as rapidly as we can. Later we will "level" the body coats to a perfectly smooth surface. Remember that we have already mixed a 2 pound cut of shellac and should be ready to proceed. The object of bodying is to build up enough finish on the instrument to allow it to be sanded level with fine sandpaper.
Glide the muneca onto the surface and move it in circular or oval patterns that overlap |
Lets start by first installing a new muneca cover. As a matter of fact, you should cut a number of 4" x 4" squares of t-shirt material for muneca covers to have on hand as we proceed If at all possible find some well worn and laundered t-shirts. They tend to be softer than new material. Now add about 8 drops of 2 pound cut shellac. To this, add about 6 drops of alcohol. After a while you will be able to accurately estimate the amounts without counting drops. Finally add a drop of olive oil. Just wet the tip of your finger with oil and rub onto the bottom of the muneca. Smack the now loaded muneca against the back of your hand (several times) to distribute the shellac. Why the back of the hand? You will want to have a clean left palm to hold the guitar tightly while you work. The most difficult part of French polishing to master is in knowing when you have the muneca properly loaded. A good gauge is to use a piece of folded typing paper placed next to your work. When you load the muneca, smack against your hand several times and then blot against the paper. If you have added too much mix, the muneca will be too wet and the blot will also appear wet. If the mix is too little, no blot will show. If you have the correct amount, the blot will appear as many individual, separated spots on the paper. Another positive indicator of a properly loaded muneca is the famous "cloud" that is left behind the muneca as it lays on the shellac. This cloud is much like the cloud that your windshield wipers leave when there is oil on the windshield- appearing and disappearing as the wipers work back and forth.
"Pulling-over" the surface using long, straight strokes. Note that the finish is building nicely. Also not the small amount of oil on the surface- indicated by the arrow. |
When the blot test shows that you have the right amount of mix, glide the muneca onto the surface of the guitar, using circular strokes, starting with the back (why the back? It is the easiest surface of the instrument to start with. It is relatively flat and has no obstructions or corners) Watch for the cloud or film of shellac left behind the muneca. Always glide onto and off of the surface of the instrument to prevent the muneca from sticking. NEVER STOP MOVING THE MUNECA WHEN IT IS IN CONTACT WITH THE INSTRUMENT. If you stop the muneca on the surface it will stick and damage the finish where you stop. Press firmly and use circular (or oval) and overlapping strokes as you cover about 13 of the back of the guitar. Move the muneca in patterns that will insure coverage of the entire surface. Be very methodical as you work. Be certain that you are getting even coverage over the area that you are working on.
Always blot the newly charged muneca on paper prior to contacting the instrument. This will help prevent damage due to an overly wet muneca. |
No, this is not the result of consuming too much ethanol during polishing. This represents a method of changing directions without stopping or lifting the muneca. |
The arrows indicate how the fingerboard or other obstruction is dealt with. Overlapping ovals are made that run up against the edge of the fingerboard. |
Spiriting
After the guitar "gases out" for about an hour, you are ready to "spirit off" the guitar. Spiriting is the procedure used to remove the excess oil that has accumulated on top of the guitar's finish.
Spirit the surface using long, straight strokes. Use less pressure when the muneca is wetter and more pressure when it is relatively dry. |
During most French-polishing processes "reading" reflections can be a valuable method of evaluating your progress. |
Review
Now, lets review the bodying procedure . . .
- Load your muneca with alcohol, shellac, and a single drop of oil. If your muneca is new you should wet it with at least 10 drops of alcohol for the first loading. Once the muneca is used, 6 to 8 drops of drops of shellac to five or six drops of alcohol will be sufficient to load the muneca from then on.
- Smack the loaded muneca against the back of your hand to help distribute the shellac/alcohol mix. Use a sheet of typing paper to blot the muneca. A wet blot means too much mixture. No blot at all means it's too dry. A water mark print means that the muneca is correctly loaded.
- Always glide on and off the guitar. Use rotating strokes, never stopping the muneca. Doing so will damage the finish where you stop.
- Be methodical. Mentally divide the guitar surfaces in sections and do each section, one at a time, assuring even coverage. Apply shellac to the surface using circular overlapping strokes followed by long straight strokes pulling over the shellac. Pressure is very, very important. In general, use low pressure when the muneca is wetter and more pressure when the muneca is drier.
- Watch for the telltale cloud behind the muneca! No cloud means that no shellac is going on to the guitar.
- Use a paper towel or dry rag to blot excess moisture from the muneca. A muneca that is too wet will damage the instrument.
- Use only alcohol while stiffing off the surface. The residual shellac in the muneca will assure that no shellac is being removed during stiffing.
- Stiff the guitar in one direction. From the heel to the tail, start from the middle and work to the edges. When stiffing the sides, start at an edge and work to the middle.
- Develop a technique that will allow you to change directions without stopping the muneca. Circular and figure 8 patterns followed by long straight strokes are used by experts.
- Pay close attention to the edges and the corners of the guitar. It is natural to neglect the edges. Always treat the edges as separate surfaces. This will assure that the finish on the edges will not be too thin
- Remember, use the oil sparingly. It is not necessary to add oil each time that you recharge the muneca. Use oil only when the muneca begins to drag or has a tendency to stick
- In most cases, twice over the guitar using circular patterns, once using straight passes, and stiffing between bodying is considered a session. Remember, the muneca is gliding over the surfaces of the guitar many times as you work methodically in an area. In actuality, you have (or should have) covered every square inch of the guitar many times during each session.
- Look over the guitar very carefully and re-pumice areas that may have been missed.
- Spirit off the entire guitar using only alcohol added to the muneca using firm even strokes.
- Continue to body for at least 4 more sessions
Glazing
Glazing is different from that of bodying the guitar by two major distinctions. First, we will use a very thin cut of shellac instead of the 2 pound cut that we have used up until now. Second, we will apply the shellac without using more straight patterns and fewer circular patterns. We will apply the shellac almost exactly the same way as we stiff the guitar. That is, we will start in the middle of the back of the guitar and apply the shellac mixture in a straight line from the heel to the tail. Circular patterns are used less often and are a method to correct problem areas. The object of glazing is simply to fill scratches left by the final leveling (sanding). Lets proceed as follows . . . You can make the thin glazing cut of shellac by simply adding several parts of alcohol to 1 part of shellac that you have been using up until now. Install a clean muneca cover and add a few drops (about 3 or 4 drops) of the 2 pound shellac. Add an equal amount of alcohol to the muneca and a drop of olive oil. Again as always, smack against the back of your hand to distribute the mix. Now, in a straight line press the muneca firmly starting from the heel and go to the tail of the guitar. Remember to glide on and off the guitar.Having adequate light will greatly help in gauging your progress. Again, good light is a must. Note the smears of oil on the surface that is being glazed. The Meguiar's #7 will remove this residue easily.
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