MIMF

This is the hottest thing in simple banjos since the cookie tin. You use the PETE plastic from a pop bottle for the head. It shrinks when heated with a hair dryer. That's why it's so HOT! Two prototypes of my take on the design: a fretless with nylon fishing line strings and violin pegs, and a fretted with steel strings and right-angle tuners. They both have a 20" scale length. The box is 6 x 11 (6.5 x 11 for the green head, it's from a 3-liter pop bottle).

Hi Jon and welcome. Without all that hardware for the head, it must be pretty light (and certainly less expensive). Using tacks to fasten the head?

I experimented with a couple of types of epoxy, but found tacks to be both easier and adequate. The clear head is held on exclusively by thumbtacks. The green head is glued with that new plastic welder epoxy, which I think would work great but the only kind I can find sets up in five minutes, which is not quite adequate working time. The PETE tends to peel off any other glue.

PETE has recycle number 1. I think all soda bottles are made from it (unless they are glass, obviously). There are many other food packages and other packages made from it also. If in doubt, heat up a little scrap and see if it shrinks.

Yes, the banjos are a little quieter than a Masterclone, especially the nylon strung one, but still as loud as a cheap acoustic guitar, for instance. There are sound files posted in the other thread - "banjo head types".

I post this frets picture reluctantly. I consider this more of a learning experience than a tried-and-true method. Some people have had success gluing the wiper blade stiffener material flat on the fretboard, using CA gel glue or epoxy. I didn't have CA gel glue, thin CA didn't hold, and I and didn't want to mess with epoxy. So, I slotted the board and inserted, leveled, crowned, and dressed the frets like normal fretwire. Now, I wish I had used normal fret wire, as the frets are too high for smooth slides. I need to try the gluing method again with the right stuff.

I noticed you used what looks like a 2 inch wide piece to strengthen the body. I've seen other banjo variants with the same thick body brace. The banjo (banjo-guitars) that I have built used a 3/4 dowel as the body brace. After working through the joining, they seem to hold just fine. I'm afraid I have missed something. How did you decide what stock to use for the body brace? (Sorry, I don't have any pictures to post, but maybe I can take apart one of my pieces. They all have resonators on the back.)

Found an old picture of how I stiffened the body.

Hello bergmatt- please note we require real first & last names here. Send me a PM with the correct info and I'll update your registration. Thanks!

bergmatt wrote:I noticed you used what looks like a 2 inch wide piece to strengthen the body. I've seen other banjo variants with the same thick body brace. The banjo (banjo-guitars) that I have built used a 3/4 dowel as the body brace. After working through the joining, they seem to hold just fine. I'm afraid I have missed something. How did you decide what stock to use for the body brace? (Sorry, I don't have any pictures to post, but maybe I can take apart one of my pieces. They all have resonators on the back.)

The "dowel stick" is 1 1/2 x 3/4 inches. Its width was chosen simply for ease of construction. I designed this banjo to sell as a kit, so much of my design criteria has to do with ease of mass production rather than strict aesthetics. The dowel stick and four rim pieces can all be ripped 1 1/2" wide, the neck blank is 2" wide, all from 3/4" thick stock. There is much that could be done to improve the aesthetics (and decrease dead weight), and perhaps I will include some suggestions on the kit instruction sheet for more ambitious builders.

I have built several banjos with a 3/4" dowel as the body brace, and several more with a nicley tapered square dowel stick.

Jon,

I am hoping to use this concept as a project for a small number of students here at our high school. I happened into a sack of empty bottles, and the cabinet shop down the block is likely going to donate some off cuts.

A couple of questions:

First, with the pieces cut, what's your estimate of assembly time for zero-little skilled workers.
Second, can you give a closer picture of how you installed the guitar tuner for the 5th string? I'd probably be able to figure something out, but I'd like to see how you did it.

Thanks! Great project.

Once the pieces are cut to length and the neck and heel ends of the dowel sticks are shaped, assembly time is pretty minimal - maybe 2-4 hours. Of course you'll want to throw some finishing time in there too.

The fifth string tuner on the steel string banjo is kind of a kludge - I've got plans for a better way but I'm waiting on some tuners to come in the mail, that got backordered.

Hi Jon,
Nice use of "found" material. It might also lend itself to use for banjo uke heads. Have you experimented with other plastics? Milk jugs might give a nice semi-frosted type head.

I haven't tried milk jugs - but my impression is they are too thick. I'm pretty sure they do shrink when heated, but it is a different plastic (recycle #2, whereas soda bottles are #1). I think maybe I will try one out.

It is possible to frost these PETE heads by sanding them with 320 grit or so.

I have made a hexagonal rim, about 8" in diameter (corner to corner, flat to flat is a little less) that I skinned with a PETE container lid. I haven't made a neck for it yet, but it will be a banjo uke.

Jon, you planted a seed in my head that's had me walking around stores like an idiot, looking at and measuring PETE 1 bottles that might be large enough to make a Minstrel Banjo ever since you first posted this thread. While at BJ's today I took a closer look at the containers they package cakes in, the lids are perfect...and I swore I'd never build another banjo.<g>

I had a couple of thoughts about this.

As I was at the Home Depot store in the garden area, they were selling seed starting kits. They had a plastic cover. Later I wondered if this would be a very large flat piece of material for your tops.

The second item was the longevity of this material. Is it going to fall apart in a few weeks or months or years? Is it UV protected?

Bob - A minstrel banjo with a PETE head - the ultimate anachronism! Go for it.

Steve - I had no idea about PETE degradation, so I did a quick Google search on it. I don't think it will be a problem under normal use. I didn't find anything indicating that it degrades in UV. It seems to take a strong acid or alkali to degrade it. One site listed PET plastic as having "fair" resistance to UV degradation. PET, as far as I can tell, is the same as PETE.

On the other hand I have personal experience that indicates the HDPE (recycling #2), the stuff milk jugs are made of, degrades in UV (i.e. sunlight) within a few years. That was for the thick buckets. I was using some for planters etc. in my back yard and they eventually became brittle and crumbly. I imagine the thinner stuff in milk jugs would be much worse.

And thanks to both of you for suggestions of larger sources of PETE banjo heads.

Here's a quick Google on plastic types. http://www.thedailygreen.com/green-home ... ics-460321

Hi Jon... you never cease to amaze me with your ingenuity!

Paul Doubek wrote:Hi Jon... you never cease to amaze me with your ingenuity!

I don't take credit for ingenuity on this one - just using other people's great ideas in my own little design. But thanks for the compliment.

Jon, I don't think you will have much problem with UV degradation of the heads as you aren't leaving them out in the weather. A good instrument would degrade out in the weather too, you know. <G>

Have any of you built a kit for these instruments that has rounded corners? Last year I had a class build wooden head banjos. These PETE head instruments might make a good ukulele project for this year. Rounding the corners would add to the ukulele nature of the instruments.

Any ideas?