October, 2011: I wrote these instructions over seven years ago, so up-front I am going to edit a few things. First, I have found a source of black pvc pipe that is not rated but has the same dimensions as the white schedule 40 plumbing pipe. I buy it from Savko Plastic Pipe in Columbus, OH. This pipe is not as hard as the white pipe, but it makes nice looking and good sounding flutes. Like the gray pvc pipe that I buy from out-of-state, the black pipe can be purchased in small quantities (20 feet) and shipped by UPS in 5 foot sections.
Secondly, rather than drilling the embouchure hole and the finger holes at the same time, as I suggest below, another way of going about this is to drill and finish the embouchure hole and insert the tuning cork before you drill the finger holes. If you plan to use a Fajardo wedge in your flute, you will also want to insert that at this time before drilling the finger holes. Below I give 525 mm as the sounding length, the distance from the center of the embouchure hole to the end of the flute, for the small 3/8" round embouchure hole. However, with a longer piece of pipe, say 590 mm rather than the 570 mm that I mention below, you can increase the sounding length (say 545 mm instead of of 525 mm) so that the pitch of the fundamental tone of the flute (before drilling the finger holes) is most likely going to be flat, if you are blowing the flute anywhere close to the way that I do. This will give you some freedom in choosing a larger embouchure if you choose to do that (oval, for example) and to match your personal embouchure to the flute that you are making. Using an electronic tuner or other known standard for pitch, see what the pitch reading is for the fundamental tone. If you are flat of D, that means that you need to remove some more material from the end of the flute. You keep repeating this process, little by little, until your fundamental tone is exactly D on the tuner. At this point you are ready to layout and drill the finger holes using the distance measurements given below.
Since writing these instructions, I have started to use a smaller hole for the hole closest to the end of the flute (for the R3 finger). Instead of the 5/16" hole that I suggest below, I am now using a 1/4" hole. This brings the finger holes for the right middle finger (R2) and the right ring finger (R3) closer together and makes the stretch easier for many people, although the tone at that hole may not be as strong as with the larger 5/16" hole suggested below. This is a trade-off that I decided to make several years ago. If you decide that you want to try using the smaller hole for R3, the hole layout can easily be determined by using the flutomat online calculator that I link below.
I'm sure that there is something else that I will need to revise in the future. Please let me know if there is something that is not clear to you, and I will try to make it more clear in my writing.
Materials and tools needed: Most PVC flutes in low D are constructed from ¾” schedule 40 PVC pipe, which is readily available in any hardware or home improvement store. The white pipe is found in the plumbing section of the store. The pipe usually comes in either 5-foot or 10-foot sections, with the 10-foot sections being the best buy. I ask the clerk to courtesy-cut the 10- foot sections into two 5-foot pieces, so that I can carry them in my car. Each 10-foot section of pipe will make four flutes. The price of a ten foot section of ¾” schedule 40 pipe should be under $2.00.
It is also possible to make flutes from the gray PVC pipe that is used for electrical conduit. This gray pipe is less dense than the white plumbing pipe, and flutes made from the gray electrical conduit do not produce as loud a tone as the denser white plumbing pipe. However, if you like the gray color and don’t mind a softer sounding flute, the flutes made from conduit are not bad.
I also order a premium gray PVC water pipe from U S Plastics in Lima, Ohio. This charcoal gray pipe is higher quality than the white plumbing pipe and is mainly for industrial applications. It is five times more expensive that the white plumbing pipe. It also has thicker walls than the white pipe, is very concentric, has a shiny smooth bore, but is slightly softer than the white pipe. Flutes made from this gray PVC require special care to keep from scratching the surface of the flute. I usually order it in 200-foot lots, and I have it cut into 5-foot pieces so that it can be shipped by UPS.
As for the tools needed to construct a simple flute, here is what I suggest. First of all, you need tools to measure with. I use a meter stick that has metric measurements. I also use a hand tape that has millimeter units. You will also need a saw to cut the ends of the flute. I did this for several years with nothing more than a hacksaw with a fine tooth blade. I now use a power miter saw with a fine (150) tooth blade. Also, you will need an assortment of hand files to finish the ends of the flute and to finish the finger holes. To finish the ends of the flute, I use a larger mill file. Your hardware store also should carry a file designed especially for filling PVC. One side is coarse and the other side is fine. To finish the finger holes I use an assortment of needle files. I like that longer ones that are 6 ½ inches long. Ebay is a good source for small needle files. I also buy files from McMaster Carr <www.mcmastercarr.com>. They carry imported, 12-piece needle file sets in a variety of cuts for under $20. I like to have fine, medium, and coarse cut files. In each file set there will be three files that are ideal for flute making. There will be two half-round files and a crossing file. The crossing file has a lenticular shape, with a curve on each side, which makes it an excellent file for flute making.
You will also need a drill and bits for drilling the finger holes. If you don’t have a drill press, a hand drill with adjustable speed will also work. It is possible to drill holes in PVC with a variety of bits, but I prefer to use inexpensive spade-point wood bits. You can purchase these bits individually (rather than in sets), and they cost less than $2 each. I do not like the speedbore bits for drilling PVC. Brad-point bits and Forstner bits can also be used as well as the inexpensive spade bits that I prefer.
Cutting the ends of the flute: The problem with using a hacksaw to cut the ends of the flute is that it is hard to make a square cut, and without power tools it takes a lot of time to square off the ends with a hand file. The method that I used to make a nearly square cut with a hacksaw is as follows: Lay a section of pipe in your lap. Starting with one finished end of the flute to your left, hook the end of a measuring tape (in millimeters) to the finished square end. Now extend the tape along the pipe and make a mark at 570 mm, which is the length of the completed flute. Rotate the flute slightly and make another mark. Continue this process until you have a series of marks around the flute. Now connect all of the dots so that you have sawing line all around the pipe. I have found it easiest to cut the pipe with the pipe lying in my lap, but you may prefer to use a workbench. I start the cut with the hacksaw, and I rotate the pipe in my hands so that I am only cutting on one side of the pipe at a time. I continue all around the pipe until the saw marks come together. However, if you happen to have a miter saw, you can make a perfectly square cut in seconds
If you use a hacksaw to cut the ends of the pipe, you will need to square off the ends of the pipe with a mill file or special PVC file. Before I was able to acquire power tools, I made several hundred flutes using this method. It works, but it is slow. I check for squareness of the ends by setting the end of the pipe on a flat surface on my table. I use a piece of ceramic tile for the hard surface. I rotate the flute and see if it appears to be perpendicular and does not wobble. I also inspect the end of the flute to see that all saw marks have been removed. If you have access to power tools and cut the pipe with a power saw, you still will need to remove the saw marks from the end of the pipe. I use a power disk sander to accomplish this, but if you don’t have a belt or disk sander, then you will need to use a hand file to remove the saw marks and finish the ends.
Laying out the finger holes: Before the finger holes can be laid out, a straight line needs to be drawn the length of the flute. It is important that this line is also straight with the flute. It is possible to draw directly onto the flute surface, but I now prefer to attach a piece of masking tape along the length of the flute. Making a mark on the center on each end of the tape, I then use those two marks to draw a straight line. I use an aluminum meter rule to draw the line. It is helpful to have two pieces of pipe lying side-by-side so that the meter rule can rest on top of the other pipe while the line is being drawn. Also, before you lay out the line for the finger holes and embouchure, check to see if the pipe is non-concentric. If it is non-concentric, it is ideal to lay out the holes on the side of the pipe that has the thickest wall thickness. This will help in cutting a better embouchure hole because of greater chimney depth of the embouchure hole due to the thicker wall on that side of the pipe.
Here are the measurements for each hole, starting from the end of the flute opposite the blow-hole or embouchure: (1) 98mm, (2) 137mm, (3) 166mm, (4) 223mm, (5) 260mm, (6) 297mm, (embouchure) 525mm. Again with two pieces of pipe lying side by side to support the measuring rule, with one hand I hold the end of the rule at the end of the flute section that I am laying out. Then with the other hand I make a small mark on the line for each of the measurements given above. I try to do this accurately to the closest millimeter. At this point the finger holes are laid out for a flute with in-line finger holes and is ready for drilling. If you wish to make a flute with off-set finger holes, the markings for the finger holes can be moved perpendicular to the line of the flute. Just as long as the distance to the end of the flute is the same for each finger hole, it doesn’t matter where you place the finger holes. Please see my flute group photo to see the spacings that I normally use for offset finger hole placement. I no longer am offsetting the finger holes as much as when the photos were taken. I think that a 2-4 mm offset is sufficient and will accommodate either standard or piper grip fingering, whereas a greater amount of offset will make piper's grip more difficult.
Drilling the finger holes: Here are the hole sizes for each of the finger holes. I explained in my Flute Buyers Guide why I am using these hole sizes. This is the same layout for finger hole position and size that I am currently using on my one-piece, 6-hole low D flutes. I have sold several hundred flutes using these measurements. Hole (1) 5/16” or 8 mm, (2) 7/16” or 11 mm, (3) 3/8” or 9.5 mm, (4) 5/16” or 8 mm, (5) 3/8” or 9.5 mm, (6) 3/8” 9.5 mm, (embouchure) 3/8” or 9.5 mm. It is OK to use either a 9 or 10 mm bit for the 3/8" hole. So you will need three wood bits, sizes 5/16”, 3/8”, and 7/16”. If you are going to drill these finger holes with a hand drill, you will also need a center punch to punch in a hole to center and guide the drill bit. I made at least 200 flutes using a hand drill. I held the pipe in vise to keep it steady while I was drilling. I used leather pads in the vise to keep from marking the PVC pipe. It also would be easy to drill the holes by laying the pipe on the floor and securing the pipe with you foot while you are drilling. With an adjustable speed drill I like to use a fairly slow speed to drill the holes. One of the problems with using a hand drill to drill the flute holes is that is difficult to keep from going through the hole and making a mark on the inside of the flute. This won’t hurt the flute in any way, but it won’t look as professional. I currently am using a 9” Craftsmen drill press with a table vise to drill the flute holes. If you use a drill press you will not need to center punch the finger holes before drilling. Also, the holes can be placed more accurately, can be drilled more round, and you don’t have to worry about drilling though and marking the inside of the flute.
Cutting the embouchure: One of the things you may notice about my flute design is that I use a fairly small opening (3/8” or 10 mm) for the embouchure hole. For a one piece-flute without a tuning slide that I am describing , it is important that the embouchure hole is not made larger or the flute will be out of tune. Larger embouchure holes will require placement of the finger holes in different positions. Cutting a good embouchure is going to take practice. But put your reservations aside, because the flute will play quite well with a very average embouchure. To do the rough cutting on the embouchure, I use one of the half-round, coarse cut needle files used for the finger holes.
Most flutes are made for right-handed players, which means that as you are holding the flute for playing, the flute body extends out to the right. I also make left-handed flutes, which extend out to the left, but don’t ask me to play one. For beginners I would recommend making a mark on the side of the blow-hole where you are going to undercut to make the embouchure. It is easy to get mixed up and ruin a flute if you happen to take off material in the wrong place. The idea is to undercut the blow-hole so that you are blowing against a wedge, allowing the air to dive down into the flute. It is good to have the blowing edge rather sharp but with a slightly rounded edge. If the wedge shape is cut flatter, the flute will take less air to blow, will create more back pressure, and the flute tone will be softer. A very steep wedge will take much more air to blow and will have a louder tone. I think that the ideal is someplace in between. There is no one-way to do this. Good silver flutes have a variety of head joints that you can buy, each with different cut embouchure for special tones. I think that you can experiment and see how your flute sounds. Once you make your first flute, you may want to make others, each time changing the embouchure slightly. That way you can compare embouchures. You also may want to look at a nice flute and try to duplicate the embouchure. The important thing is not to change the outside shape or diameter of the blow-hole, unless, of course, you plan to adjust the placement of the finger holes. Contrary to what you may find on many flutes, I also like to round the top edge of the blow-hole that is against my lips. This feels better to me than a sharp edge.
Finishing the finger holes: To make a good sounding and attractive flute you will need to spend some time finishing the finger holes. I use several different cuts of needles files to do this. It is possible to do this with power rotary tools (such as Dremmel), but I don’t recommend this for two reasons. With rotary tools it is easy to remove too much material and thus change the tuning of the hole. Also, high-speed rotary tools put a lot of dust in the atmosphere. And, friends, it isn’t a good idea to breathe in PVC dust, wood dust, or any kind of dust for that matter. Hand filing takes longer, but you have a lot more control, and the dust is minimal.
Before you start filing on the finger holes, however, you need to decide what kind of finger holes you want. Some people believe that finger holes without round top edges are easier to cover. However, I like to round the top edges of my finger holes. I like the way they feel better, and I have no problem covering them with my fingers, although you do need to press harder to seal the hole. One person has described my finger holes as “comfy”. If you make several flutes, you can try both ideas. I also think that it is a good idea to slightly round the bottom side of the finger holes. This reduces resistance and allows the air to pass more smoothly through the flute and out the finger holes. Final adjustment of the finger holes will be discussed later.
Finishing the surface of the flute: If you are just looking for a practice flute or a flute to bang around in your car on in a backpack, you may well be satisfied with the plain unfinished PVC pipe with the plumbing markings. However, you may want to do something else with the surface of the flute. Here are a few suggestions. The first thing that comes to mind is to paint the surface of the flute. This can either be done with a brush or spray can. At first I hand painted designs on the flute with a brush. After that I tried to spray paint the surface, but I had difficulty with the paint running. Also, with time the paint began to peel off near the embouchure and the finger holes, so I have given up with trying to paint the surface. However, you may be more imaginative and successful than I have been.
Another idea that has worked very well for me is to cover the surface of the flute with a wood-grain vinyl. You can see what the finished flutes look like in my group flute photo. As far as I am aware, I am the only person who is covering PVC flutes with wood-grain vinyl. I purchase the rolls of vinyl in the home improvement department of large stores such as Walmart. The rolled vinyl (shelf paper) that I use is Contact brand, and it comes in 24- foot rolls by 18 inches wide. Each roll costs about $6. Don’t try to use the extra thick or ultra material. You will have to experiment with this. Some of the vinyl is too soft, and it is very difficult to work with. In the last year Contact brand has changed some of their products, and materials that I had been using for years no longer seems to be suitable.
Before I apply the vinyl to the flute, I first wet sand the surface of the flute with 400 grit sandpaper. I do this in my kitchen sink. I then dry off the flute, and on the back side of the flute with regard to the finished finger holes I draw a straight line with pencil from end to end on the flute. I then cut a piece of the adhesive-backed vinyl that is slightly longer than the flute and is 100mm wide. The 100mm width will allow for just the right amount of overlap. PVC pipe is very conducive to static-electric cling, so in order for the next step to be successful you need to have clean hands and a clean work area. Make sure that the PVC pipe is free from any PVC dust that likes to cling to it. Now you are ready to remove the adhesive backing from the vinyl. Using the line on the back of the flute, I start from one end of the flute and I adhere the edge of the vinyl to the flute body until I have the vinyl attached along the length of the flute. Holding the flute with both hands and allowing the vinyl sheet to hang free, I then use my thumbs back and forth along the flute applying the vinyl to the flute body. Continue doing this until you have completed the overlap. This is a tricky process and will take some practice. The idea is to apply the vinyl without any dust or air bubbles getting under the vinyl in the process. If you are not happy with the first attempt, just peel off the vinyl, cut another piece of vinyl and try again. This operation can be a good lesson in learning patience.
Once you have the vinyl successfully applied to the flute body, you are ready to trim the excess vinyl from the ends of the flute and to reopen the finger holes. I do this with an x-acto knife. The final step in the process is to refinish the PVC/vinyl edges on both ends of the flute and the finger holes. On the ends of the flute I use a fine tooth mill file to refinish the vinyl edge. To do the same thing for the finger holes I use the sharp edge of a crossing needle file.
The last way that I am going to mention to finish the surface of the flute is to polish it. After I complete the finishing of the finger holes and the embouchure, I wet sand the flute with 400-grit sandpaper, removing the plumbing markings from the back of the flute. I then wash and dry the flute and look closely for any deep scratches that I have missed. Now is the time to remove any scratches before going any further with the process. Once you are assured that there are no deep scratches, you are ready to continue with the second sanding, where I use a special 1000-grit automotive wet sandpaper. I recommend Nikken sandpaper (made in Japan). It is the best that you can buy, and it is available in automotive supply stores. I continue the sanding process with 1500 grit Nikken sandpaper. Since this article was written, I am now using 320, 400, 600, and 1200 grit paper to wet sand the flute prior to the final polishing.
At this point it is possible to complete the final polishing with a soft rag and polishing compound. However, to speed up the process, I use a simple polishing machine that I have adapted from a bench grinder. I removed both of the grinding wheels from the bench grinder, and I replaced one of the wheels with a cotton polishing wheel of the same diameter. I also covered the holding platform with felt so that the surface of the flute would not be scratched. I use a stick polishing compound called Tripoli (brown). After applying the polishing compound to the revolving cotton wheel, I start to complete the final buffing of the flute. The flute will begin to appear highly polished quite quickly. It is important to wear a breathing mask when doing this. Using the high speed polishing wheel, you will need to be extra careful polishing near the embouchure and finger holes. If you don’t do it right, the cotton wheel will dig in and start removing too much material. I have ruined flutes at this final stage because I wasn’t careful polishing near the sharp edge of the embouchure. I have learned from experience how to do this successfully. The end result is a beautifully polished flute in less than 10 minutes of work for the final polishing.
Shaping and inserting a tuning cork: I have a friend who has a catering business save wine corks for me, and these are the corks that I use as tuning corks in my flutes. From one good wine cork I can usually make three flute corks that are ½ inch thick. I cut the corks with a small fine tooth hobby saw, and I smooth the end surfaces with a sanding paddle. Wine corks come in a great variety of diameters, so you will need to adjust the diameter so that it is an ideal diameter to act as a tuning cork. You want the cork diameter to be slightly larger than the inside diameter of the flute body so that you will have to compress the cork to insert it into the flute. That way the cork will stay in place once you position it in the flute. If the cork diameter is too large, you will need to remove some of the cork material around the cork with a file or sandpaper. I use bastard files for this purpose. However, if the cork diameter is too small, which is often the case, I wrap the outside of the cork with ½ inch drafting tape until I have the suitable diameter. Wine corks have been penetrated with a corkscrew so that oftentimes part of the center of the cork is missing. I remedy this by using a kitchen knife to spread wood putty over the ends of each cork. After the wood putty is dry I sand off the excess and paint the end surfaces with a light brown latex paint to cover-up the wood putty filling. After drying the cork is now ready to insert into the flute. Also, if you happen to live near a wine making store, you may be able to purchase new wine corks instead of trying to repair a used corks like I have always done. However, my one attempt to purchase a suitable cork for flute making in a wine store was unsuccessful.
I use a 5/8 inch diameter wooden dowel to insert and position the cork stopper. The stopper adjusts the intonation of the flute so that the flute is in tune with itself. The standard position for the cork stopper is one bore diameter (distance) from the embouchure edge of the cork to the center of the embouchure hole. I make a mark on the dowel at this distance from the end of the dowel. When I insert the cork stopper, I look for the mark on the dowel to be in the center of the embouchure hole when the stopper is in the correct position. Playing without the Tipple-Fajardo wedge in place, it may be wise to adjust the stopper a little closer to the embouchure hole to improve second octave intonation. Once you have positioned the tuning cork in that position, you are ready to test the flute with a tuner, some other instrument like a keyboard, or by ear. With all finger holes covered play the fundamental low D. Now play the second and third octave D notes. With the wooden dowel adjust the tuning cork so that all of these notes are on pitch. Try several of the other notes in this manner, as well. At this point the flute is ready for the final "voicing" or fine tuning adjustment of the finger holes.
Final Adjustments: With a tuner or other reference standard, as you listen to the intonation of the first and second octave notes at a given finger hole, you will find that the second octave notes may be flat, especially for the smaller finger holes and for the notes near the upper part of the second octave. To help remedy this, it is a good idea to undercut the embouchure side of the finger holes. This will raise the pitch of the second octave note . This is a very common practice in flute making. With a coarse file you will need to remove a modest amount of material without changing the top view appearance. Remember, you only need to undercut the bottom edge closest to the embouchure. Keep checking with a tuner until you are satisfied with the intonation of the notes at each fingerhole.
Since there is a difference in the way people blow a transverse flute, you may find some discrepancies when you check each note with a tuner. You can change the tuning of each finger hole by making it larger or smaller or by making it closer or farther away from the end of the flute. Making the finger hole larger will sharpen the tone of that hole. Making the finger hole smaller will flatten the tone of the hole. Moving the finger hole closer to the embouchure will sharpen the tone of the note. And moving the finger hole closer to the end of the flute will flatten the tone of the note. If you find that you do want to make some changes, make some notes about what you want to do with each finger hole. Then when you lay out the next flute you can make some adjustments to the finger hole position. I recommend adding 1mm to the layout position of a finger hole to sharpen it slightly. And conversely, subtract 1mm to the layout position of a finger hole to flatten it slightly. It is also possible to sharpen the tone of a finger hole of an existing flute by enlarging a finger hole with a file. I also sometimes reduce the size of a finger hole by apply white glue around the edge of the finger hole with a toothpick. Let the glue dry between repeated applications. This process will flatten the tone of that hole. For a quick fix you can also flatten the tone of a finger hole by covering part of it with a piece of tape.
Finally, it is also possible to change the overall pitch of a flute by changing the shape and size of the embouchure hole. The finger hole measurements that were given were for a round embouchure hole with a 3/8" or 10 mm diameter. Normally, with a two-piece flute with a tuning slide, pitch changes can be accomplished by moving the tuning slide. However, with a one-piece, non-tunable flute the overall pitch of the flute can be sharpened by increasing the area of the embouchure hole should you need to do this.
If you would like to try making a flute in another key, I suggest using the flutomat calculator by Pete Kosel. http://www.cwo.com/~ph_kosel/flutomat.html
I hope that you enjoy your flute.