Potting pickups; tape before or after?

[Marko Ursin]

Hello all,
I'm really newbie on winding pickups. I wanted to try to make a Wal-inspired bass pickup and found some very, very good info on this forum. I made bobbins out of acrylic and I have eight of them wound to 2,45 Kohm. Should I tape the coil before or after potting? I read somewhere that tape doesn't like to stay on coil when potting, but how does it stick to paraffin? Also how can I keep the coil unwinding as there is just wires soldered to the coilwire, held by a piece of tape at the moment. Is it even possible to pot the coils with tape over them? Does the paraffin seep inside the coil even when it's covered with tape? Attached is a pic of a bobbin and a wound coil.
Marko

[Mark Hammer]

You really don't want to expose the adhesive on tape to high temperatures.

The other thing is that you want to be able to wipe off the excess wax after dipping, and having tape in place gets in the way of that.

[David Schwab]

I tape first and then pot. I do that to get the coil nice and tight. I use a rubber band around the coil to stop the tape from coming off. The wax does get all the way into the coil.

I let the bobbin drip a bit and then wipe it with a paper towel and let it cool off on a piece of aluminum foil.

That's a nice looking bobbin.... It looks very familiar...

[Marko Ursin]

Thanks for the replies. I guess the way David does is the one I'm going to do. Is there something special to look for when choosing tape? Looks like some use cloth tape and some use plastic tape.
David; There really is a lot in common on your and my bobbins It was your project and great info and help that got me interested in trying to make this kind of pickup. Thanks!
Marko

[David Schwab]

I use black paper tape. You can also use the cloth tape.

[belwar]

Hello all,
I'm really newbie on winding pickups. I wanted to try to make a Wal-inspired bass pickup and found some very, very good info on this forum. I made bobbins out of acrylic and I have eight of them wound to 2,45 Kohm. Should I tape the coil before or after potting? I read somewhere that tape doesn't like to stay on coil when potting, but how does it stick to paraffin? Also how can I keep the coil unwinding as there is just wires soldered to the coilwire, held by a piece of tape at the moment. Is it even possible to pot the coils with tape over them? Does the paraffin seep inside the coil even when it's covered with tape? Attached is a pic of a bobbin and a wound coil.
Marko

WOW! Very nice! I made my first 16 of those bobbins by hand on my lathe... what a pain in the but. Please post how it goes!

I've gone to tons of work to replicate that pickup. I had Wal pole screws made from the same alloy, The exact size magnets from the same material, made the keeper bar from the same alloy.. now im working on the circuit board base plate

Please keep us updated with photos of your progress

[David King]

I have done both ways and now pot first and tape later. The tapes stick just fine to the cold wax. I actually tested a lot of tapes to see if any will hold up in a hot wax bath. The best so far was the 3M green masking tape for lacquer but it did start to peel. The high temperature polymide tape failed miserably as did the black masking tape and the brown freezer tape.
I now put a tight layer of teflon plumbers tape while the wax is still warm and pliable, once that cools I cover it with the black artist tape.

[David Schwab]

WOW! Very nice! I made my first 16 of those bobbins by hand on my lathe... what a pain in the but. Please post how it goes!

Matt, you act like I didn't do those same bobbins the same way 2 years ago... I even told you how I did mine! We had this whole conversation over the phone. I guess you forgot... Making them from nylon washers was my idea.

I also gave the dimensions and wire gauge to Marko two weeks ago.

Nice work Marko BTW. A little too nice! You did those from acrylic, right?

I've posted this photo many times here.

[David Schwab]

David; There really is a lot in common on your and my bobbins It was your project and great info and help that got me interested in trying to make this kind of pickup. Thanks!
Marko

Well small round bobbins will look the same! Yours look a little taller.

My idea was to find a way to do them without having to make all the bobbins totally from scratch. I make my own bobbins for my other pickups, and having to make eight for one pickup is a lot of work.

It's pretty easy this way. You did a great job.

Now I'm really waiting to see Matt's version. His is going to be exact.

[belwar]

Matt, you act like I didn't do those same bobbins the same way 2 years ago... I even told you how I did mine! We had this whole conversation over the phone. I guess you forgot... Making them from nylon washers was my idea.

Oh I didnt forget! - I think your idea of making them using washers was/is brilliant! I was looking at his bobbins and they are 1 piece no? I was marvelling over the 1 piece work - or did he use your method with washers? My comment was in reference to the fact that the prototypes I've made so far have been one piece from Delrin Rod, lathed to size. No offence was meant to your stellar effort so far! :>

I actually think this style pickup would sound better with a squatier fatter bobbin myself - but im so stuck in PAF ways I cant change anything :/

Im pretty sure the MK1 and the MK3 have different sized bobbins - the MK3 having taller bobbins.

[belwar]

Now I'm really waiting to see Matt's version. His is going to be exact.

Yeah, but I have no plans for public sales. Gotta buy a bass to get them!

Im slowly saving for the bobbin injection mold - It takes me about 1.5 hours to make enough bobbins for 1 bass. That is FAR too long at my $8/h wage. The bobbin mold will cost about $1800, and the cover mold is about $3500. That's not chump change by any means.

I've actually been thinking about putting a wal style jazz p/u together.. 4 coils at around 10k.

[Marko Ursin]

Thanks for your comments guys! My bobbins are made of 2mm acrylic and acrylic tube. I just hope ca glue holds up the potting temperature. I used 22mm hole drill with center drill to get enough acrylic washers and then used my drill press a lathe to turn them smaller. It certainly is not a too fast way of making them, but for single/couple of pickups it's acceptable. They are 17,5mm diameter as I'm making this pickup for 54mm string spacing. Then I glued these acrylic washers to 19mm pieces of acrylic tube. There was JUST enough room to get enough wire for 2.45Kohms. I'm going to use 5mmx19mm Alnico or Neodymium rods as magnets. Now I have to pot the coils and make the base out of circuit board. I'm going to make part of the connections on the board.
Marko

[David King]

I'm just curious as to why these would need bobbins at all? Seems like they could just be wrapped around magnet (over some tape) and between two temporary, non-stick washers that would get peeled off after potting and reused.

[Marko Ursin]

I thought about winding over magnet and washers on the ends. The center drill on my hole saw is 8mm so that makes it a bit difficult. Maybe if I sawed the washers and drilled a 5mm hole on the center it would work.
Marko

[David Schwab]

Oh I didnt forget! - I think your idea of making them using washers was/is brilliant!

I know, I was teasing you. The size is almost exact. It was a happy discovery. It took me days to find the right combination though.

I was looking at his bobbins and they are 1 piece no? I was marvelling over the 1 piece work - or did he use your method with washers? My comment was in reference to the fact that the prototypes I've made so far have been one piece from Delrin Rod, lathed to size. No offence was meant to your stellar effort so far! :>

Obviously he'll answer this, but I think they are one piece. I was wondering this too.

I actually think this style pickup would sound better with a squatier fatter bobbin myself - but im so stuck in PAF ways I cant change anything :/

Me too. That's actually something I'm working on. Curious to hear how they sound.

Im pretty sure the MK1 and the MK3 have different sized bobbins - the MK3 having taller bobbins.

Are they smaller in diameter? I could see them being taller so they can be placed closer together.