I want to build a driver and am going to start winding my own VC. I will use 24AWG magnet wire (it is the only size I have and I have a lot of it). I am going to use an aluminum beer can for the former and was going to wrap it is Kapton tape. I was wondering what thickness I should use. Also, what glue should I use to hold the VC in place? Could I use polyurethane? I have Minwax fast drying clear gloss polyurethane and clear gloss Minwax Helmsman spar urethane. Would these work? Thanks
Can't help you with the glues, but remember to put a slit in the aluminum former or it will act as a shorted turn and dump the efficiency in the toilet
Hmm, put a slit in the former? Can the ends of the slit touch or can it not touch at all? Thanks for that info, I didn't know that.
That Loctite link was interesting. They make good stuff, pretty pricey too though. I know for bonding the VC to the spider and cone I was told I can use any 5 min epoxy (could probably use that for most of the glueing needs. I didn't see anything for the VC to the former though.
That Loctite link was interesting. They make good stuff, pretty pricey too though. I know for bonding the VC to the spider and cone I was told I can use any 5 min epoxy (could probably use that for most of the glueing needs. I didn't see anything for the VC to the former though.
The former is split all the way, there's a pic on this page that shows the gap in the former.
And this is a pretty important, the glue is the first thing that fails when a voice coil overheats. I can see 2 ways of doing this;
1. wind the coil, then use a very thin consistency epoxy that will penetrate the layers to bind everything together.
2. use a very slow setting epoxy and wind the coil "wet", messy but you would be more assured of full glue penetration.
And this is a pretty important, the glue is the first thing that fails when a voice coil overheats. I can see 2 ways of doing this;
1. wind the coil, then use a very thin consistency epoxy that will penetrate the layers to bind everything together.
2. use a very slow setting epoxy and wind the coil "wet", messy but you would be more assured of full glue penetration.
search for a thread called DIY dynamic driver
I posted a spreadsheet to help you predict parameters.
I posted a spreadsheet to help you predict parameters.
Thanks for all the information, I appretiate it. Now that I saw that pic of the former I remember seeing the ones I have taken apart like that too. For Kapton tape would this work...
4 Inches Wide x 36 Yards Long x 1 mil Thick
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From C.S. Hyde Co. Product# 18-1S
I will try winding wet with slow drying epoxy. What kind shout I get, from Home Depot would be great. Any other tips with information would be excellent.
4 Inches Wide x 36 Yards Long x 1 mil Thick
--------------------------------------------------------------------------------
From C.S. Hyde Co. Product# 18-1S
I will try winding wet with slow drying epoxy. What kind shout I get, from Home Depot would be great. Any other tips with information would be excellent.
I think most five minute epoxies, even when fully cured, soften considerably under heat. Maybe loctite tech help could give some
assurance on this. May or may not be an issue for you.
assurance on this. May or may not be an issue for you.
I'll look into that. What about the Kapton tape? Is there something else that would be cheaper or do I need Kapton? Thanks
If this is just an experimental project, then no, you do not NEED kapton. You're about to increase your daily language expletives if you're going to hand wind a coil 😉
Hardly professional, but this might be of interest: http://www.vikash.info/audio/transducer_design/
Hardly professional, but this might be of interest: http://www.vikash.info/audio/transducer_design/
An externally hosted image should be here but it was not working when we last tested it.
No problem on the winding. I have made a tesla coil before. I wound 24AWG magnet wire on 4" OD PVC for 24" It took long but turned out great.
Bloomington is certainly large enough to support a couple of adhesive specialty wholesalers/vendors. Look one up in the yellow pages. A couple of years ago I was looking for a particular epoxy type for potting electronics. It was just a one-off experiment, but I needed something with specific
properties - hence, I could hardly deal with really expensive half gallons of the stuff. I explained to a local vendor what I was doing, and they very graciously gave me a sample/trial pac of exactly what I needed. Sounds like your project is similar.
It's not as if they have to worry about bringing a horde of pocket-protected nerds down on their heads for free samples - fortunately, we are relatively few.
There are epoxies specifically formulated for efficient heat transfer (probably critical in your case). There are myriad viscosities available - too high and it wont fill properly; too low and it'll end up a puddle on your workbench. Cure times vary as well and can be used to control flow properties.
If you're lucky, you might run into someone with a great deal of technical knowledge at ye olde adhesive shoppe and a soft spot
for diy'ers. You'll get a sample of just exactly what you need.
Oh hell, this may all just be overwrought, maybe you'll just want to
use mucilage (but then again, you are a man who's winding his own voice coils - and many of us can certainly relate to that)
properties - hence, I could hardly deal with really expensive half gallons of the stuff. I explained to a local vendor what I was doing, and they very graciously gave me a sample/trial pac of exactly what I needed. Sounds like your project is similar.
It's not as if they have to worry about bringing a horde of pocket-protected nerds down on their heads for free samples - fortunately, we are relatively few.
There are epoxies specifically formulated for efficient heat transfer (probably critical in your case). There are myriad viscosities available - too high and it wont fill properly; too low and it'll end up a puddle on your workbench. Cure times vary as well and can be used to control flow properties.
If you're lucky, you might run into someone with a great deal of technical knowledge at ye olde adhesive shoppe and a soft spot
for diy'ers. You'll get a sample of just exactly what you need.
Oh hell, this may all just be overwrought, maybe you'll just want to
use mucilage (but then again, you are a man who's winding his own voice coils - and many of us can certainly relate to that)
I think polyurethane would work. The only question I have is will it stand the heat? On my tesla coil I brushed it on and it soaked into the layers, I used Helsman after because it is thicker and coated it until you couldn't even feel the wire anymore, it was smooth. It worked great and held everything in place very strong. I tried searching the the temp max but couldn't find anything.
DKAudio said:
Maybe you could call Minneapolis speaker company and ask?
Or you can experiment and do trial and error.
DKAudio, do you already have the pole pieces/magnet? If you are going to machine the pole pieces it's ok, otherwise you'd have to match the former to the gap available.
I wouldn't suggest the beercan to stay with the coil for ever. Better use a thin sheet of teflon over the can and wind the coil over this, so that the coil can be slipped out after the glue sets. Choice of glue and how neat you can apply it are critical to final result.
Do post your experiences.
Good luck!
I wouldn't suggest the beercan to stay with the coil for ever. Better use a thin sheet of teflon over the can and wind the coil over this, so that the coil can be slipped out after the glue sets. Choice of glue and how neat you can apply it are critical to final result.
Do post your experiences.
Good luck!
I wonder if that type of adhesive would be good for high temp?
I mean it's better for heat transfer...
It would melt or not?
http://www.arcticsilver.com/arctic_alumina_thermal_adhesive.htm
I mean it's better for heat transfer...
It would melt or not?
http://www.arcticsilver.com/arctic_alumina_thermal_adhesive.htm
I thought they used aluminum formers. Where can I get teflon? I don't have anything machined and don't have access to a machine shop. I haven't thought about what I am going to do for the basket, motor structure. I have tons of ceramic doughnut magnets though.
In which case you probably want to start at a motor structure first, not fit a motor to a VC. First place to start with all this is usually FEMM.
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