Hi all,
I'm almost ready to start winding some small air core coils for some speaker crossovers and will be trying to get the values as precise as possible. I'll be doing the "periodically scratch some insulation off and measure" method to get there, but can't find enough info on recoating the temporarily stripped parts of the wire to continue winding.
I have both spray and brush on lacquer here (Deft brand), as well as the usual polyurethanes and stuff. I'd like something where I don't have to break for an hour waiting for it to harden, as I'm not sure how many times I'm going to have to scratch and test. I know the Deft stuff dries quickly (and smells horrible
), but I'm not sure how it handles any bending of the wire as I proceed to wrap, or if that's even the right type of coating at all.
Any tips on it would be appreciated,
George
I'm almost ready to start winding some small air core coils for some speaker crossovers and will be trying to get the values as precise as possible. I'll be doing the "periodically scratch some insulation off and measure" method to get there, but can't find enough info on recoating the temporarily stripped parts of the wire to continue winding.
I have both spray and brush on lacquer here (Deft brand), as well as the usual polyurethanes and stuff. I'd like something where I don't have to break for an hour waiting for it to harden, as I'm not sure how many times I'm going to have to scratch and test. I know the Deft stuff dries quickly (and smells horrible
), but I'm not sure how it handles any bending of the wire as I proceed to wrap, or if that's even the right type of coating at all. Any tips on it would be appreciated,
George
Well, I'd just scrape a bit off one side of the wire, enough to get a crock clip on and then not worry about it. Make sure that the scraped bits don't line up (do them at 90° intervals or several turns apart. You can varnish the whole thing after if you want.
Or, wind it too long and cut bits off til it's right although with the price of copper this isn't prudent.
You've estimated the coil dims & turns with equations right?
Or, wind it too long and cut bits off til it's right although with the price of copper this isn't prudent.
You've estimated the coil dims & turns with equations right?
Thanks Iain,
So it sounds like it isn't too critical just as long as the scraped sections don't short together then. I should be able to work with that, but may wipe something on them just for the heck of it.
Yeah the "start oversize, then trim down" seemed to be what most of the DIY stuff I found suggested. For right this second, I'm not dealing with an abundance of magnet wire though, so I may not do that until I can get a whole batch of it from somewhere.
I did run across online calculators and stuff for getting in the ballpark, so I will be doing that first, as well as comparing to some coils here that use about the same gauge of wire and coil diameter.
Thanks again,
George
PS- What should I look for as far as setting them after they're sized (any particular type of varnish)? Also, does that act to secure the whole coil and keep it neat, or is it just for chemically sealing it? I don't like the wire wrap idea. If they have to be mechanically secured as well, I'd probably rather go with a glob of something.
So it sounds like it isn't too critical just as long as the scraped sections don't short together then. I should be able to work with that, but may wipe something on them just for the heck of it.
Yeah the "start oversize, then trim down" seemed to be what most of the DIY stuff I found suggested. For right this second, I'm not dealing with an abundance of magnet wire though, so I may not do that until I can get a whole batch of it from somewhere.
I did run across online calculators and stuff for getting in the ballpark, so I will be doing that first, as well as comparing to some coils here that use about the same gauge of wire and coil diameter.
Thanks again,
George
PS- What should I look for as far as setting them after they're sized (any particular type of varnish)? Also, does that act to secure the whole coil and keep it neat, or is it just for chemically sealing it? I don't like the wire wrap idea. If they have to be mechanically secured as well, I'd probably rather go with a glob of something.
Have you priced coils from a supplier like Parts Express. I have found them reasonable in the past. If they don;t have your value exact, I recall needing a 2.7mH, so I bought a 3mH and unwound it til it was right. No scraping repairs needed.
COnsidering my own lack of motor skills, their product came already nicely wound, and solid, none of my uneven shoddy work. Plus it only took a few moments with the LCR meter.
COnsidering my own lack of motor skills, their product came already nicely wound, and solid, none of my uneven shoddy work. Plus it only took a few moments with the LCR meter.
Hi,
I think that may be where the wire was from originally (either Parts Express or MCM). Does sound like a good way to go, but if I end up doing a bunch, I'd probably just as soon get a big spool of it from someone. I should already have enough for this current project on hand.
Haven't started on the winding unfortunately. I set up a nice system of testing/deciding on my crossover types and frequencies using bi-amping to the drivers with hi/low passing being done by software EQ on the computer, but there's so damn much to pick from. I can't decide how to test and arrange for the flattest response, as I don't have access to a properly tuned space right now.
Take Care
George
I think that may be where the wire was from originally (either Parts Express or MCM). Does sound like a good way to go, but if I end up doing a bunch, I'd probably just as soon get a big spool of it from someone. I should already have enough for this current project on hand.
Haven't started on the winding unfortunately. I set up a nice system of testing/deciding on my crossover types and frequencies using bi-amping to the drivers with hi/low passing being done by software EQ on the computer, but there's so damn much to pick from. I can't decide how to test and arrange for the flattest response, as I don't have access to a properly tuned space right now.
Take Care
George
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