disappointment

[nabiul]

Try using a polyethylene cutting board for the base, stuff is so slippery that even epoxy will come off of it in time, and I've used epoxy to glue anodized aluminium to blued steel!

Cutting boards are cheap enough too, I got 4 small board like this at canadian tire for like $5.

[simonbaker]

Your coil making is very interesting.
I worked many years with all sorts of resins, molds, fiberglass, wood laminates, glues, etc. so maybe I could give you some useful tips.

Porous materials, like wood, must be sealed first with wood sealer, thick paint, resin or such. Then apply several thin coats of floor wax, then apply the silicone anti-adherant.
For fiberglass boats, I used PVA, that is POLYVYNIL ALCOHOL. This is dissolved in alcohol and water soluble, so it can be washed off with water after de-molding.

The plastic channel is a good idea. Aluminium will not work.

If you use the PP spacer shown below, to make a molding channel, the spacer will provide the distance between the coil and the shield.
This material is often used instead of cardboard. It is made of Polypropylene which is a good dielectric.

The next picture is my coil jig. The acrylic disk turns on a center axle and is coated with wax and PVA, so that the epoxy resin does not stick on it.

Tinkerer

Thanks for sharing your experience -- I was naive about making non-sticky wood.

I love these contraptions; it's like Faraday himself is walking amongst us...or someone's planning time travel....

Looks like you are making a concentric coil there?

If you use the PP spacer shown below, to make a molding channel, the spacer will provide the distance between the coil and the shield.

Do you feel there should be a space between the coil and the shield? Why so?

-SB

[Tinkerer]

Your coil making is very interesting.
I worked many years with all sorts of resins, molds, fiberglass, wood laminates, glues, etc. so maybe I could give you some useful tips.

Porous materials, like wood, must be sealed first with wood sealer, thick paint, resin or such. Then apply several thin coats of floor wax, then apply the silicone anti-adherant.
For fiberglass boats, I used PVA, that is POLYVYNIL ALCOHOL. This is dissolved in alcohol and water soluble, so it can be washed off with water after de-molding.

The plastic channel is a good idea. Aluminium will not work.

If you use the PP spacer shown below, to make a molding channel, the spacer will provide the distance between the coil and the shield.
This material is often used instead of cardboard. It is made of Polypropylene which is a good dielectric.

The next picture is my coil jig. The acrylic disk turns on a center axle and is coated with wax and PVA, so that the epoxy resin does not stick on it.

Tinkerer

[simonbaker]

Holy cow! Mine have come apart relativey easy. Another idea is to cover youf plywood with wax. Nothing will stick to it then. I have used wax when I ran out of dry mold realease agent. I just got a block of beeswax and rubbed the wood really good.

My very first form I used, I covered everything with wax paper, I got a long knife and slowly peeled the wires away.


Just a few idea.

Don

Thanks for ideas... I live and learn. A good wax job sounds like the right approach. Maybe work on my bikini line also (I didn't say that...).

I haven't yet pried the coil off the bottom wood and pegs -- trying to find my wife's plastic pan scraper, has nice sharp edge. (Why do I always end up using my wife's kitchen stuff more than my own tools? Is this normal? Yes, no... maybe?)

I'll keep trying...

-SB

[dfbowers]

My first coil using "coil winder sandwich" and lacquer bath -- not so good. In spite of spraying the wood thoroughly with silicone "non-stick" spray, my coil, coated with varathane as it was wound, stuck to the wood form, and windings were separated as I removed the top wood piece. Some wood actually broke off and stuck to the coil wires. Maybe the varathane is much stickier than Spar Varnish or able to penetrate the silicone. Or maybe I need much thicker silicone coating.

I will try to rescue the coil by wrapping in tape, but I'm disappointed with my method. It also is very slow waiting for varathane to dry, so can't make lots of coils in a hurry.

I think I chose to high a gap for the coil height - the coil thickness is too thin, not square enough cross-section.

I would like to find a way to wind directly onto a light form that can be incorporated into the coil head, similar to the video showing Tesoro making coils. I may try again my "foam core form" that almost worked:

http://www.geotech1.com/forums/showpost.php?p=98902&postcount=129

The problem was the heavy wires forced the layers open. With lighter wire and using the new top disk on my coil winder "sandwich", maybe I can be more successful with it. However, it is not a professional looking coil and not the ultimate technique.

I would like to try some thin plastic channel, bent in a "D" shape, to wind the coils on. Then move the plastic channel into a normal vacuum formed shell or resin molded form. I don't know where to find such plastic channel.

There is some thin aluminum channel at the hardware store that would make an interesting experiment. The aluminum would act as a shield -- but maybe too much metal near the coil, it is much thicker than foil. The aluminum channel would be difficult to bend and require cuts at the bend points probably. Just a wacky idea.

Anyway, I'll try to perfect my "glue while winding" technique with more non-stick spray.

-SB

Holy cow! Mine have come apart relativey easy. Another idea is to cover youf plywood with wax. Nothing will stick to it then. I have used wax when I ran out of dry mold realease agent. I just got a block of beeswax and rubbed the wood really good.

My very first form I used, I covered everything with wax paper, I got a long knife and slowly peeled the wires away.


Just a few idea.

Don

[simonbaker]

My first coil using "coil winder sandwich" and lacquer bath -- not so good. In spite of spraying the wood thoroughly with silicone "non-stick" spray, my coil, coated with varathane as it was wound, stuck to the wood form, and windings were separated as I removed the top wood piece. Some wood actually broke off and stuck to the coil wires. Maybe the varathane is much stickier than Spar Varnish or able to penetrate the silicone. Or maybe I need much thicker silicone coating.

I will try to rescue the coil by wrapping in tape, but I'm disappointed with my method. It also is very slow waiting for varathane to dry, so can't make lots of coils in a hurry.

I think I chose too high a gap for the coil height - the coil thickness is too thin, not square enough cross-section.

I would like to find a way to wind directly onto a light form that can be incorporated into the coil head, similar to the video showing Tesoro making coils. I may try again my "foam core form" that almost worked:

http://www.geotech1.com/forums/showpost.php?p=98902&postcount=129

The problem was the heavy wires forced the layers open. With lighter wire and using the new top disk on my coil winder "sandwich", maybe I can be more successful with it. However, it is not a professional looking coil and not the ultimate technique.

I would like to try some thin plastic channel, bent in a "D" shape, to wind the coils on. Then move the plastic channel into a normal vacuum formed shell or resin molded form. I don't know where to find such plastic channel.

There is some thin aluminum channel at the hardware store that would make an interesting experiment. The aluminum would act as a shield -- but maybe too much metal near the coil, it is much thicker than foil. The aluminum channel would be difficult to bend and require cuts at the bend points probably. Just a wacky idea.

Anyway, I'll try to perfect my "glue while winding" technique with more non-stick spray.

-SB