I have planned to wind coil former for my home subwoofer 15 inch two of them (and yes I got many more .
BTW,I am not a noob in this and had resurrected many of loudspeakers before.
so far one thing which troubled me was the right adhesive for the coils.
I have wound formers on aluminium sheets and kapton former. and you wont believe what I used as glue was "Araldite" yeah the epoxy, same mixing and pasting thingie.
as you may have realized, anomalies were bit too serious, araldite is just common purpose glue ,not at all hifi.
it is too viscous adding undesirable weight to former.
I wish to know if there is anything available like "henron voice bonder" or similar thing which I can buy online for small quantity.I realized henron no longer supplies this kind of adhesives anymore.
Please advice.
BTW,I am not a noob in this and had resurrected many of loudspeakers before.
so far one thing which troubled me was the right adhesive for the coils.
I have wound formers on aluminium sheets and kapton former. and you wont believe what I used as glue was "Araldite" yeah the epoxy, same mixing and pasting thingie.
as you may have realized, anomalies were bit too serious, araldite is just common purpose glue ,not at all hifi.
it is too viscous adding undesirable weight to former.
I wish to know if there is anything available like "henron voice bonder" or similar thing which I can buy online for small quantity.I realized henron no longer supplies this kind of adhesives anymore.
Please advice.
All the coil winding I did used adhesive pre-coated on the wire. For example, see this link: MWS Wire Industries - Bondable Magnet Wire
You can probably make many different types of glue work as long as they give you the strength you need at the upper temperature limit you are working at and are easy to apply in the right quantities.
You can probably make many different types of glue work as long as they give you the strength you need at the upper temperature limit you are working at and are easy to apply in the right quantities.
Thanks John.
As you said it temperature and strength, yes I believe if manufacturer have such a glue specifically for voice coil winding I can use it with closed eyes.
Right now I am experimenting and they have all failed.some are too brittle some remain soft, rubbery some changed their character after short term use.
so it has become deemed necessary to find out right kind of adhesive for proer result.
The pre-coated wire you mentioned I am dead sure It is not available in my country and the one shown in website do they ship internationally in small quantity?
I believe solvent bonding should be the appropriate one for my purpose.
As you said it temperature and strength, yes I believe if manufacturer have such a glue specifically for voice coil winding I can use it with closed eyes.
Right now I am experimenting and they have all failed.some are too brittle some remain soft, rubbery some changed their character after short term use.
so it has become deemed necessary to find out right kind of adhesive for proer result.
The pre-coated wire you mentioned I am dead sure It is not available in my country and the one shown in website do they ship internationally in small quantity?
I believe solvent bonding should be the appropriate one for my purpose.
Epoxy,*is* the standard voice coil wire adhesive, but there are many types and viscosities.
Araldite makes hundreds of different types, you need one which is somewhat thicker than honey; no more, no less.
It also hardens in *hours* at ambient temperature (up to 8 to 16 hours ar 20ºC), only way of speeding that is placing it in an oven (up to 100ºC which cuts curing time to less than an hour; any more and it bubbles); absolutely forget "10 minute" cr*p.
I don´t remember by heart *which* Araldit I used but its viscosity was as I just said, and it was mixed in a 2:1 ratio, maybe that´s enough for you to find it in their huge catalog.
The one I´m using now *is* Araldit made (or so the seller claims) but he buys it in 200Kg drums and reloads (and relabels) 250g and 1Kg cans so the brand and type is local, not much use to you.
You must slightly heat the die around which you wind it, for it to become slightly more liquid and "wet" the surfaces better.
Apply a little too much and then wipe the excess.
It hardens very rigid , yet heat and impact resistant.
You must use anodized aluminum or slightly scratch its surface with #600 emery paper or it won´t adhere to aluminum´s oxide "glass" surface.
Same with Kapton.
Good luck.
PS: I have been making my own voice coils for almost 40 years now.
Araldite makes hundreds of different types, you need one which is somewhat thicker than honey; no more, no less.
It also hardens in *hours* at ambient temperature (up to 8 to 16 hours ar 20ºC), only way of speeding that is placing it in an oven (up to 100ºC which cuts curing time to less than an hour; any more and it bubbles); absolutely forget "10 minute" cr*p.
I don´t remember by heart *which* Araldit I used but its viscosity was as I just said, and it was mixed in a 2:1 ratio, maybe that´s enough for you to find it in their huge catalog.
The one I´m using now *is* Araldit made (or so the seller claims) but he buys it in 200Kg drums and reloads (and relabels) 250g and 1Kg cans so the brand and type is local, not much use to you.
You must slightly heat the die around which you wind it, for it to become slightly more liquid and "wet" the surfaces better.
Apply a little too much and then wipe the excess.
It hardens very rigid , yet heat and impact resistant.
You must use anodized aluminum or slightly scratch its surface with #600 emery paper or it won´t adhere to aluminum´s oxide "glass" surface.
Same with Kapton.
Good luck.
PS: I have been making my own voice coils for almost 40 years now.
jayadev,having been in the same situation many times,I have found it necessary to speed up the drying process when using 'Araldite(marketed in Australia by Selleys) as the bonding material.By doing this,the moisture contamination is reduced and the mixture thins, allowing any excess to be wiped away.A simple method of doing this procedure is by way of using a variable dc power supply connected to the freshly wound voice coil and allowing the current flow to bring the curing temperature to a suitable level.With aluminium formers it does pay to rub down the surfaces with a fine grade of wet and dry paper to remove any protective coating that may have been applied. I am not fond of the wetted wire technique as I have come across too many failures in the past,especially the blue coated variety and the tendency for the winding to seperate under moderate heat.Also the coil rigidity is improved with epoxy and the heat treatment.
Vanarn, I get you.
But what my concern is the undesirable weight of epoxy adhesive and of course quick dry is major advantage.
I have stripped many voice coils to figure out what they might be using but all the time I am left with despair. My observation is manufacturers, use very low viscosity adhesives which spread out evenly and they withstand high temperature with very good bonding strength.
Araldites which I have used so far is as thick as honey and when dry they are very far from uniform over the winding- I hate to see that!!
I am sure there are experts laughing at me in this forum. I am not manufacturer or high end expert but an audio enthusiast...this is the only way I got!!
But what my concern is the undesirable weight of epoxy adhesive and of course quick dry is major advantage.
I have stripped many voice coils to figure out what they might be using but all the time I am left with despair. My observation is manufacturers, use very low viscosity adhesives which spread out evenly and they withstand high temperature with very good bonding strength.
Araldites which I have used so far is as thick as honey and when dry they are very far from uniform over the winding- I hate to see that!!
I am sure there are experts laughing at me in this forum. I am not manufacturer or high end expert but an audio enthusiast...this is the only way I got!!
The answer for your winding method is to control the tension of the wire that allows it to displace the 'Araldite" at room temperature. A more liquid adhesive that spreads everywhere is not helpful.To repeat myself,heating a freshly wound coil,before curing takes place,results in the situation where the honey-like viscosity changes to a watery composition,which allows for the surplus to be wiped away and this ensures that the unwanted mass is kept to a minimum.If you achieve the correct methodology you will end up with a voice coil replacement that is better than what most manufacturers use especially if you add a reinforcement sleeve to the v.c.former neck and carefully bond the the assembly to the cone apex.
Mr Bear, You are right . but if not right kind of bonding means weaker coil and peace of mind goes down the drain.
I have so far wound one 15 incher but it never had to go through enourmous power so it is still healthy and working since last 3 year.
But when I am thinking to build highpower subwoofers with double magnets,thats where I am worried!
You might consider purchasing already built voice coils?
I would think that they could be had mail order from a number of sources... aftermarket "re-cone" shops might also be of help in that regard. Of course there are OEM plants around the world too. Probably a few in India as well... maybe they are even a source for small quantities of the adhesives and coatings you want. etc.
_-_-bear
I would think that they could be had mail order from a number of sources... aftermarket "re-cone" shops might also be of help in that regard. Of course there are OEM plants around the world too. Probably a few in India as well... maybe they are even a source for small quantities of the adhesives and coatings you want. etc.
_-_-bear
Hi VaNarn, can you elaborate on this.
I ask because I have some Dynaudio (I think) woofers where the vc formers got crushed. I have straightened them out but wanted to add some reinforcement. The former is blue aluminium.
Thanks, sp
You bet ,I can make better coils than those sold in market for a given driver after measuring there magnetic gap and related.
but issue is procurement of raw materials.
Small quantity general purpose adhesives are of no use for something like a voice coil,I hope one can visualize what all things goes with a coil when it moves in and out of magnetic gap.
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stoolpigeon,as a first step a crushed neck needs to be straightened by sliding a close fitting tube inside the coil and pressing out the creases gradually.The 'blue' would be an adhesive coating used as part of the wet bonding method.This coating can be removed with acetone,As an aside,early Dynaudio speakers were labelled, 's.e.n.-lab' and if this is the case then you are likely to have the paper cone versions.I would suggest that a sleeve made from drawing paper (0.125mm) bonded to the neck with super strength, 'Araldite would fix the problem.A suggested method would be to apply a thin layer of epoxy to the cleaned aluminium only and fit the sleeve to the neck by aid of an elastic band (or two).
Thanks Vanarn.
Let me share my experiences.
I used to wind on paper when I was in school that is 15 years ago.(now I am 29 ). it was easy to wind but wouldn't last with much heat or moisture .
then when I was in college I procured aluminium sheet ,which i realized from then Sony mid hifi.
strangely the coil from sony speaker would slide down the gap as it should be but my Alumium former showed mild magnetism ,it was bit reluctant to move in and out so loss of efficiency probably which I never measured..yet I made many and they worked well even now it is working.
Then 4 years back I laid my hands on Kapton when my 15" (P-audio)subwoofer got smoked.
I removed the former and found coil was burnt but kapton was intact so I used same former replaced with same gauge coil and it was near perfect but lost some details in upper bandwidth ,probably the adhesive or new cone paper was the culprit.
so I am on kapton now I have roll laying in my home bought from ebay. it is definitly a blessing for modern day life.
Now I need a right Adhesive to start with it again in proper manner,trial and error lead me with no happy conclusions so far..
Experts please help.
Let me share my experiences.
I used to wind on paper when I was in school that is 15 years ago.(now I am 29 ). it was easy to wind but wouldn't last with much heat or moisture .
then when I was in college I procured aluminium sheet ,which i realized from then Sony mid hifi.
strangely the coil from sony speaker would slide down the gap as it should be but my Alumium former showed mild magnetism ,it was bit reluctant to move in and out so loss of efficiency probably which I never measured..yet I made many and they worked well even now it is working.
Then 4 years back I laid my hands on Kapton when my 15" (P-audio)subwoofer got smoked.
I removed the former and found coil was burnt but kapton was intact so I used same former replaced with same gauge coil and it was near perfect but lost some details in upper bandwidth ,probably the adhesive or new cone paper was the culprit.
so I am on kapton now I have roll laying in my home bought from ebay. it is definitly a blessing for modern day life.
Now I need a right Adhesive to start with it again in proper manner,trial and error lead me with no happy conclusions so far..
Experts please help.
For an answer see:
http://www.google.com/url?sa=t&rct=...vZmiCw&usg=AFQjCNEhjZ4QUTVgCTiOVAg1w2jh7bQv6w
Loudspeaker - Markets - Henkel
Regards,
WHG
Hi WHG.
But I did not find anything related specifically "coil to former" type product in those. I think improvisation is the way.
Thanks
Jay
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