Making low gauge (2 - 00) stranded wire from CRT deflection/focusing coil windings

Discussion in 'General Electronics Chat' started by RogueRose, Sep 27, 2016.

  1. RogueRose

    Thread Starter Member

    Oct 10, 2014
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    I am wondering about using the wires from the focusing/deflection coil windings. They are basically enameled magnet copper wire. The gauge varies depending upon the size of the CRT gun but I think they are usually 26-36g and they have an enamel and a high voltage rating.

    I've uncoiled many of these and have made spools of them. I separate each thread (usually 5-6 per coil, all same length). So one winding would make 5-6 spools of about 100ft each.

    For a few different applications, having very flexible well insulated wire is very helpful and having as little outer insulation that is thick and fairly inflexible is very helpful. I've tried car audio wire of 4 -0 gauge and the insulation outer wall thickness is more than that of the wire in many cases! This is to protect against abrasion in automobiles.

    The plan is to determine the needed length of wire (let's say 10 ft) and then make a bobbin/spool that is maybe 11ft (gives 6" leeway on each side), and then wrap the wire around the bobbin. The number of turns determines the gauge. Once the desired gauge is reached the wire is cut and heat shrink tubing seals the ends to hole them together. Then the wire is pulled through heat shrink tubing (300v rating, some 450v or 600v) and heated to shrink. Now the wire has the enamel insulation (HV rated) as well as the shrink wrap insulation. The ends of the wire are cleaned with a solvent that removes the enamel to allow contact conductivity.

    My main question is whether I should remove the enamel from all of the wire or if removing just the ends is sufficient. The ends will be soldered into a solid wire so I don't think there is any issue with lack of contact - but - there will not be contact throughout the inside of the wire which IDK if this matters or not. This is my main question and concern and want to know fi there are any other things which I should take note of.

    This wire is going to be used for low voltages from 2-14v AC.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Why would you think there is reason or need for removing the enamel, apart from connection points?
    Max.
     
  3. RogueRose

    Thread Starter Member

    Oct 10, 2014
    189
    4
    I figured there wasn't but I'm pretty sure if I were to remove the insulation on thick car audio power wire, all the little wires would be making full contact with their neighboring wires. I didn't know if this contact helps provide more conductivity or had any other benefits or needed attributes.

    IMO I thought it best to keep it on as it gives that extra insulation at minimal thickness. I also didn't know if it would add unwated heat.

    The benefit of doing what I am doing is that I can use a thicker gauge wire than may be "required" as it is much more flexible and can be fitted into the space available. I figured a little extra gauge would help if there was any heat buildup(eliminate/reduce heating)
     
  4. RichardO

    Well-Known Member

    May 4, 2013
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    You have missed one important step. The bundle of wires must be twisted before shrinking the tubing. If the wires are left straight then the cable will be extremely stiff. Also, chose the un-shrunk diameter of the tubing relative to the cable diameter to set the final thickness of the outer insulation.
     
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  5. RogueRose

    Thread Starter Member

    Oct 10, 2014
    189
    4

    Thank you for stating that! I think I'll do what I see in heavy gauge wire and create many 10-14g twisted strands and then twist them all together.

    My one concern is that if one is twisted more and say the length is 11ft but twisted it is 10.75 and another is 11ft straight and twisted to 10.85, when I twist them all together and clamp the ends for soldering as a solid wire, will the .1ft difference cause a problem? I'm suspecting that it would. I'm sure that I can get them pretty close and a 1" difference over 11 ft is more than I would realistically allow, I'm just wondering if it matters.

    As a note, I'm looking at using this to re-wind MOT's and have various voltage outputs as the # of wrappings differs. This is just one of maybe 3-4 applications. Ideally I would like to be able to make flat braided wire but IDK how I could heat shrink that and whether it would be necessary with the enamel.

    AS far as the last scentence I bolded, I'm not clear. Let's say the twisted wire is .66" thick. Are you saying chose a .66" (or maybe .7") diameter tubing for this? I have used very tight fitting shrink tube and it always seemed to work well (though usually for 18-24g).

    Thanks again for the suggestion!

    One last question, is there any problem with mixing gauges like 36, 32 and 28? I would probably keep them all twisted in groups but twist mixed groups into the larger wire. I'm just curious if this would be an issue.
     
  6. RichardO

    Well-Known Member

    May 4, 2013
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    I would guess that if some groups of wire in the cable are twisted slightly more than others the cable will be stiffer -- but not much.

    The tubing gets thicker when it shrinks. If you chose tubing that is a lot bigger than the wires then the tubing will get a lot thicker when it shrinks to the wire size.
    If you choose tubing that is just big enough to accept the wires then the tubing shrinks very little so the walls of the tubing only get a little thicker.

    I have no idea. Try it and let us know. :D
     
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  7. RichardO

    Well-Known Member

    May 4, 2013
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    I should have described the "right" way to twist the wires.

    First, tie the bundle of wires to a solid, stationary point.

    Second, put the other end of the cable into the chuck of a drill.

    Third, use the drill (either manual or electric) to twist the wires. Keep tension on the cable so it does not knot. The cable will get shorter as this happens, of course.

    Finally, and this is important, yank on the wire to set the twist. The yank helps keep the cable from untwisting or knotting up.

    You will have to experiment how many twists per inch you need. I would start with a twist typical for twisted pairs.
     
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  8. RogueRose

    Thread Starter Member

    Oct 10, 2014
    189
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    THANKS for the replies and info! I am thinking of sing the slow (400rpm) speed on my drill and counting seconds. I don't know how else to do this other than counting each revolution (uuggghhh). The hardest part is not having the wire break in the chuck or at the vice.
     
  9. RogueRose

    Thread Starter Member

    Oct 10, 2014
    189
    4
    I'm toying with the idea of just cutting the insulation off the car audio power wire and putting heat shrink tubing on it. The thing is that the wire, for 4-00 gauge seems to be aluminum as it is silver in color but I have heard that some is tin coated. The wires are very fine and the sites say it is 100% oxygen free but being 36-42g strands, how much of that is copper and what is the silver coating?

    http://phoenixgold.com/catalog/wiring-kits/SK6241

    http://www.rockfordfosgate.com/products/details/rfk4x
     
  10. tcmtech

    Well-Known Member

    Nov 4, 2013
    2,039
    1,667
    Seems like a huge overall waste of time and money to me. :rolleyes:

    Why spend $150+ for 20 feet of 4 gauge wire when you can go to you local welding supply or even most hardware stores and get the same or better grade cables for around a dollar a foot at most.

    Or if you're just going to cut the insulation off stop by your local metal recycling center and buy used cable by the pound for scrap price and while you rather maybe pick up a few higher wattage HID lighting ballasts and toss the crappy MOT units out and work with some decent grade transformer material??
     
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  11. RogueRose

    Thread Starter Member

    Oct 10, 2014
    189
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    I would absolutely do what you say but for some reason the scrap yards around here never allow people to buy stuff "because of liability" I tell them "i'm melting it down" or "it's for rifle targets" and they refuse... Only once did I get the go-ahead to take some stuff and the buy said "take what you want - I'm sure I'll be looking at my monitor when you do it". Well, I couldn't do that as I felt like I was stealing and I didn't want to end up having to explain to cops.

    Around here it seems either buy new, salvage from appliances on Craiglsit or buy used stuff on craigslist. It's super frustrating b/c I see truckloads of stuff I would pay above scrap price (+10% or so) if I could get it before they scrap it, but the salvage yard don't like that.

    As for the car audio stuff, I already have lots of that stuff, mix n match from 10 - 2g in various lengths. I just didn't want to cut it up b/c some people pay good $$ for it as you see.
     
  12. RichardO

    Well-Known Member

    May 4, 2013
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    @RogueRose
    I keep forgetting to mention the first time I saw cable that was made using magnet (i.e. enamel coated wire). It was in a very small video camera. The camera was less than 1/2 inch in diameter and the cable was equally small in diameter. The cable was very flexible.

    The cable was made from three twisted bundles of very small wire -- one bundle each of power, ground and video. The color of the enamel on the wire bundles were red (power), black (ground) and yellow (video). The bundles were twisted inside the outside jacket. There were no jackets around the bundles.
     
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