This instructable is specifically for bass, so there are four magnets required. For a guitar, obviously you will need six smaller ones. Also, it's good to have a bunch of extra magnets lying around as it will make the project go quicker.
Step 1: Materials
- A spool of insulated copper wire. Different gauges will produce different sounds, but you want something very thin.
- Two Popsicle sticks. These can be new or used.
- 8 neodymium magnets (2 for each string). These should be less then the width of the Popsicle stick. Again, different sizes will produce a different sound. You can see the rough size of what we used here.
- Gorilla Glue
- Some Wax/beeswax or potting epoxy
I used 42 gauge wire. You need to strip the ends before soldering them to your electronics. You can do this with your finger nail. If you dont have this around, it will raise the cost of your pickup by about $25.
The magnets I used were .32 or .37 in diameter and .2 tall.
A stronger magnet = hotter output and more high frequencies (better for guitar)
You can do the same thing for a guitar, cept you will need 6 rod magnets.
Step 2: Getting Started
Start off by eating your two Popsicles. This is probably the most difficult part of the process. You may want to enlist the help of a friend. If they're the kind of Popsicles that have hidden messages on the stick or fortunes, go ahead and read them. Pat yourself on the back, you're done with step one.
Put the Popsicle stick up to the strings, and mark where each string hits. You can see the marks on the sticks in the picture below. This will be a guide for where you need to place the center of each magnet. You are now ready to begin construction
Step 3: Construction
You will need to glue the first four magnets to the Popsicle stick. This is not as easy as it sounds since all the magnets will just stick together until the glue is set. This is where the extra magnets come in handy. Place the other four magnets on the other side of the stick from the magnets being glued to hold them in place.
Once you've got your glue dried, just put the other 4 magnets on top of the 4 that are glued to the Popsicle stick. Then glue the other Popsicle stick to the top. Use the extra 4 to help hold the stick down, since gorilla glue expands (another reason why you only just use a small amount per magnet).
File away any excess glue before you continue.
It does not matter if you have negative or positive pole facing up, as long as you do EACH ONE THE SAME.
Step 4: Wrapping the Wire
Leave a foot or two sticking out before you start wrapping. This is important, because you need to connect your electronics to two leads.
I found it helpful to stick the whole thing to the refrigerator while you wrap it. Get comfortable because you're going to be there a while. Keep wrapping until it gets barely big enough to fit inside the plastic of your old pickup (it isn't necessary to have an enclosure - it just looks nice). This will be several thousands of wraps, but I didn't really count. The normal number of wraps is between 5000 and 8000. It should look about like the completed picture below.
Note: More windings = hotter output. The more windings you do, however, will begin to roll off the top frequencies.
If the wire breaks while you are wrapping you will need to start over. So don't break the wire - it's very fragile.
Step 5: Potting
What you will want to do is cover/pot the pickup in either natural scented wax or with a potting epoxy. Beeswax works great for this, and is what I used (my pickup does smell a bit like honey). You just need to get some from a craft store like Hobby Lobby, put the wax in a coffee can, and place the coffee can with the wax in a pot with warm water for a few minutes. I say warm because you dont want this to get too hot. If you burn through the insulation on the wire
it can cause a short... which means the pickup will either not work well, or not at all. If you are worried about this, you might just want to use a potting epoxy.
Potting a pickup (dipping in wax) reduces microphonics, preventing the wire from vibrating in the magnetic field. Increasing the turns of wire (5000 - 8000 are somewhat standard numbers) will roll off high frequencies the same way an inductor does in a low pass filter.