And there's the Hot Split Pickup housing mold! In purple silicone! With built-in dowel pins to align the base plate. That's the process.
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Magnets & Copper Wire: A Pickup Building Thread
- Thread starter Freekmagnet
- Start date
Weekly update:
I’ve been plugging along with my “completed” prototype. I built up a whole pickup, cast it in white resin and glued a nickel-silver cap on to the face of it. Here’s the rough:
The encapsulation itself went OK - everything seems to have survived. The white resin was problematic at best. I had a lot of pitting which sucked. Also, you could pretty much see the poles and the magnets through the resin. I’m probably going to have to paint it, which I’m not too excited about.
The next thing is the nickel-silver cap - I glued it on there with CA glue and it definitely did not hold. I’ve used epoxy before, and that didn’t hold either. I’m going to try Gorilla Glue tomorrow and see how that goes.
So, once I get the cap glued on and sanded down, I’ll fill the pits with CA glue and finish the resin parts with WB Polyurethane mixed with white. Hopefully that’ll hold up with regular playing.
I don’t think I’ll be doing a white encapsulation again. If I want to do a white pickup I’m going to have to use another approach.
I’ve been plugging along with my “completed” prototype. I built up a whole pickup, cast it in white resin and glued a nickel-silver cap on to the face of it. Here’s the rough:
The encapsulation itself went OK - everything seems to have survived. The white resin was problematic at best. I had a lot of pitting which sucked. Also, you could pretty much see the poles and the magnets through the resin. I’m probably going to have to paint it, which I’m not too excited about.
The next thing is the nickel-silver cap - I glued it on there with CA glue and it definitely did not hold. I’ve used epoxy before, and that didn’t hold either. I’m going to try Gorilla Glue tomorrow and see how that goes.
So, once I get the cap glued on and sanded down, I’ll fill the pits with CA glue and finish the resin parts with WB Polyurethane mixed with white. Hopefully that’ll hold up with regular playing.
I don’t think I’ll be doing a white encapsulation again. If I want to do a white pickup I’m going to have to use another approach.
How are you mixing and pouring the white resin? I wonder if the pitting could be avoided. When I cast parts like this, I mix the resin in a disposable cup. I try to be careful to not mix in air bubbles, then let the resin sit and tap it on the table for a few minutes so the bubbles can rise to the top. I mix extra resin so there will be plenty of excess in the cup. Then I poke a hole in the bottom of the cup and let the resin pour out from the bottom, so the air bubbles at the top of the cup end up staying put in the excess left in the cup, and aren't introduced to the part.
When I've had really problematic parts I've (carefully!) run a random orbit sander with no sandpaper on it up against the side of the mold after pouring the resin in, to help work the bubbles out.
When I've had really problematic parts I've (carefully!) run a random orbit sander with no sandpaper on it up against the side of the mold after pouring the resin in, to help work the bubbles out.
The resin colour looks great though. Last time I made a white 2-part resin cast, it turned a very pale lemon yellow. 
That’s a good technique! I’ll have to try it next time. I just mixed the resin in a Dixie cup and poured it in. I’ve never had much problem with air bubbles, but this part is pretty complicated; lots of places for pesky little air pockets. The even bigger problem was that you could see right through it.
The resin colour looks great though. Last time I made a white 2-part resin cast, it turned a very pale lemon yellow.
I used the Smooth-On white resin. It mixes clear and gradually clouds up into white as it cures. The color itself is really good - it’s a nice, bright white. But as I said, I could see the parts right through it.
Spray paint the coil assembly white before casting it?
Haha that’s a really good idea, Bruce. I’m only laughing because that solution is so simple and so painfully obvious that it literally hurts.
When I was casting my pickups in black epoxy, before I started using the ebony caps, the tops of the magnets would show through the top surface. Solution: I cut a rectangle of black construction paper to fit down in the bottom of the mold. I poured in a little bit of epoxy, set the paper on it, placed the coil assembly on it, and poured in the rest of the epoxy. It worked very well, made the top "cap" skin of epoxy completely opaque.
I'm sure you could do the same thing with white construction paper, if you don't want to mess with the nickel-silver cap.
I'm sure you've seen these, but here's what Keith and I did to dress up the first set of the special pickups for the 10-string basses. The top caps are made from thin aluminum. You've got to make those custom pickups cool-looking.
I'm sure you could do the same thing with white construction paper, if you don't want to mess with the nickel-silver cap.
I'm sure you've seen these, but here's what Keith and I did to dress up the first set of the special pickups for the 10-string basses. The top caps are made from thin aluminum. You've got to make those custom pickups cool-looking.
You could slip a length of white shrink tube over the assembly and shrink it down before casting. Would keep it from showing through and would be quicker than waiting for paint to dry.
That is definitely cool-looking!
The paper idea is a good idea.
I think I’m going to build another shape. This one is too complicated and I don’t need those ear thingys. That’ll allow me to take a couple of different approaches. I have another set of coils ready to go that I set aside in case attempt #1 went south. The main thing is that the coils survived intact.
Just for the heck of it, I dropped that pickup I made into the test bass.
The good news is that it works and sounds great. I now know that I can build, assemble and encapsulate this pickup and I don’t have to worry too much about it.
The bad news is that I decided that while I could make this shell design work, I’m going to do another one. So, I gotta go back to the drawing board. Last night, I stayed up late carving a new shape.
The old shape is on the top/background and the new shape is on the bottom/foreground. The idea is that I can more easily put a cap on top or shielding on the sides and then just grind it smooth on the ROSS. I made the little ends flare up to give some extra thumb planting space. We’ll see how it goes - I liked the retro dog-ear style of the old shape, but when my casting went south, I realized that because of the square edge, there wasn’t too much I could do about it.
The new shape is growing on me. I think it’ll work with the “vintage modern” vibe I’m striving for with this new bass.
The good news is that it works and sounds great. I now know that I can build, assemble and encapsulate this pickup and I don’t have to worry too much about it.
The bad news is that I decided that while I could make this shell design work, I’m going to do another one. So, I gotta go back to the drawing board. Last night, I stayed up late carving a new shape.
The old shape is on the top/background and the new shape is on the bottom/foreground. The idea is that I can more easily put a cap on top or shielding on the sides and then just grind it smooth on the ROSS. I made the little ends flare up to give some extra thumb planting space. We’ll see how it goes - I liked the retro dog-ear style of the old shape, but when my casting went south, I realized that because of the square edge, there wasn’t too much I could do about it.
The new shape is growing on me. I think it’ll work with the “vintage modern” vibe I’m striving for with this new bass.
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I don’t know if this is applicable to how you guys cast pickups but if you watch Peter Brown or Nick Zametti’s YouTube channels they use a pressure pot to get the air bubbles out when making something out of resin.
haha I’m not that high-tech! A pressure pot would be nice, though. If ever get a real shop with space, I might invest in one of those.
There are some on amazon that should fit a pickup housing for under $100. That and a compressor is all you need.
In production, you could use some kind of white-tinted paint or glue for the potting, dunking the whole assembly...
