What kind of lacquer for bonding bobbinless coils?

[Marko Ursin]

I'm going to wind a few bobbinless coils. I already have a jig for the coils and one test coil is wound. I used ca for bonding the coil and while it's curing I thought about using lacquer to bond the coil. What kind of lacquer would be safe for insulation of the wire? I thought I'd brush the coil with lacquer while winding it.

[jonson]

I'm very careful with CA on coils as I have had it burn through the insulation in the past. 2 pack polyurethane is hard to beat and potlife whem mixed is good for a 3 or 4 hours and a good few coils. Build it as you go. Never liked cellulose for coil work as cellulose thinners and acetone are very close and that can lead to coil breakdown. A good 2 pack PU is available from Sayerlack Italy and distributed by Sherwin-Williams but you are looking at 6 litre packs plus 3 litre hardener packs but if you are just winding pickups with it then look on the net for a company that does smaller quantities. I have used and gotta say you will get your best success with self bonding wire that you can soak the coil in alcohol or pass a small charge through to get the bond. Kent always used just wax and he had it off to a fine art which I've not seen anybody repeat since.

[Marko Ursin]

I also thought about vacuum potting with wax. I'll have to make some test coils as soon as my wire arrives.

[David King]

Motor armature and stator coils are routinely dipped in a special coil varnish and then baked for hours in an oven. The process stinks but it seems to work since they've been doing the same thing for a hundred years. I imagine that the varnish is cheap because they buy it in big drums. It never dries until it is baked.

Bruce Johnson has been using the water-thin Smith's CPES epoxy which also stinks but he claims good success with little or no failure rate.

[jonson]

That's the problem certainly in the UK David. It comes in very big drums and difficult to get smaller quantities unless you befriend an armature rewinder. Clear stove enamel lacquer is available in much smaller tins and can be baked in an oven or with an infra red lamo.

[Joe Gwinn]

Use solvent/heat bondable magnet wire?

MWS Wire Industries - Bondable Magnet Wire

[Bruce Johnson]

Like David said, I've been using CPES epoxy to pot all of my pickups for a long time. I haven't ever made any bobbinless coils, but the CPES should work fine for them. It has a viscosity about like water. You dab or pour it on, or dunk the coil if you want. It soaks all the way through the coil and locks all the wire together. It doesn't harm the insulation or heat up at all. Fully cured, it stays just a little bit rubbery. It's not brittle hard like CA glue. In my experience, it's the perfect potting material.

[Marko Ursin]

I can get CPES in 1 litre package and that's way too much epoxy and cost. How about thinning laminating epoxy with alcohol or acetone? West System says that thinned epoxy will harden flexible and rubbery. Brocott (the wire I'm using) says that their polyester wire coating is unaffected by all common solvents.

[soundmasterg]

I wonder what Adeson uses on the air coil Tri-Sonic clones that he makes.....he's in the UK and isn't a huge manufacturer...whatever he uses seems to work well...I suppose I could email and ask him but I'm too lazy...haha.

Greg

[restorationad]

I wonder what Adeson uses on the air coil Tri-Sonic clones that he makes.....he's in the UK and isn't a huge manufacturer...whatever he uses seems to work well...I suppose I could email and ask him but I'm too lazy...haha.

Greg

I emailed Adrian a few years ago and he was nice enough to reply. I dug up the email and he said

"The original 60's units all had tape-wound coils"

I would think that since his units are true reproductions he is using tape to hold the coils together.

[David King]

I think thinned down, slow-cure epoxy would work just fine. I would thin by 10% or less with acetone or zylol.

[David Schwab]

Kent Armstrong winds bobbin-less coils. We winds them on a form, and then pots them in wax. When the wax is cool he takes them off the form. The wax keeps them together.

[Joe Gwinn]

Kent Armstrong winds bobbin-less coils. We winds them on a form, and then pots them in wax. When the wax is cool he takes them off the form. The wax keeps them together.

Then he pots it in epoxy. The wax will prevent breakage due to tempco mismatch, an issue discussed in another thread.

[Marko Ursin]

I'll try vacuum wax potting first. I'm scared that the wires coming from the coil may break easier with harder bonding. The finished pickup will be cast in epoxy after wiring has been done. We'll see how this will work after the wire I ordered arrives.

[David King]

That sounds easier than tying dozens of little strings around the wire all the way around the coil. I've seen that on at least one old pickup.