Enamelled wire manufacture

[akis]

Hello,

I would like to insulate a small, flat conductor (2.5cm2) using a very durable material. For example the polyurethane used to enamel copper wires is very sturdy, and does not come off, unless you either file it, or heat it up to 400C.

Polyurethane is typically sold as wood varnishing (eg yacht varnish), but when I apply it on a surface and let it dry, it is possible that it will peel off, if you pull hard enough.

I presume that the manufactured enamelled copper wires although using polyurethane, they must use some other process that makes the coating really tough (and flexible).

I presume if I take a clean copper wire and dip it into polyurethane and then pull it out and let it dry, it will not be the same as the industrially made enamelled copper wires.

Does anyone know what the exact process of enamelling is so that I may apply it onto my flat conductor?

Many thanks

[SeanB]

Take your copper strip, clean it in solvent, then use some fine waterpaper to clean the surface of oxides, and roughen it, then wash again in solvent and dry. Then dip in the varnish and leave to dry, then bake for a few hours to harden it.

enamelling is a glass coating applied and then melted to the copper, and needs some clean substrate, and a slurry of glass powder in a gum arabic suspension ( to make it a slurry) that is then fired in a reducing atmosphere ( no more oxide forming) to melt the glass into a layer on the surface.

Cheaper is to use a thermosetting plastic and lower temperature in an oven, or to use an automotive epoxy paint instead, less need for high temperature, and pretty durable, plus easy to get in colours and a clear as well.

Look for enamelling or powder coating for a number of parts, or just a small amount of paint from a local car paint shop for onesies.

[calexanian]

They usually either electrolytically clean or etch the wire, or sometimes even both before coating it to give a clean surface that the coating will bond to. I like the mentioned epoxy paint approach. I would as said clean it in a good solvent then lightly burnish it with sand paper or steel wool then apply a high quality paint. Perhaps even multiple coats of spray conformal coating since you know it will have good electrical properties. I might even consider plastidip or some such thing. Glyptal paint would also be very good, but it can be hard to find.