DIY thermo-bonding wire - RC Groups
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Jul 22, 2004, 01:14 AM
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peter frostick's Avatar

Thermal bonded micro coils

I've seen very little mention of the "Microplane solutions" website instructions on DIY thermal bonding wire? ----- this could be because it only appears on the original French text version; and not in the English translation.

The basic technique is to pull the enamelled wire through some slightly diluted Baslaloc covering adhesive, and feed it between finger and thumb onto the coil winding former. The former I used was a steel rod with a few turns of waxy backing paper from double sided tape; the sides of the former were short lengths of silicone fuel tubing; the reason being that it can take the 160C oven temperature needed to set the adhesive! The experimental coil/magnet in the picture is a 160 Ohm unit weighing 0.17 grams, and wound with 0.04mm wire. Internal diameter is 3mm. This is as small a gauge of wire as I ever wish to work with again!!! Cooking time is 20 minutes in domestic oven at 160C, and results are very clean as long as you blot off all surplus adhesive prior to baking!

The very high Ohmage used is because the idea is to run it direct from the ports of a PIC in a super light IR system in the Ztron style. Initial tests at Lipo voltage are giving 0.25 Gram/Cm torque; not too shabby in an 8" span model!!

The system is destined for a Spitfire ot Thunderbolt, and has been spurred on by Graham's noble R&D efforts with direct drive micro props; not too mention those beautifully CNCed foam fuselages!!

Wish me luck! Peter
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Jul 22, 2004, 03:49 AM
Sticky Shepherd
Graham Stabler's Avatar
Hope you don't mind Peter but I thought more would see the method if I made it a seperate thread

Jul 22, 2004, 04:32 PM
Designer of Flying Things
-=SLaPPiE=-'s Avatar
That is a nice clean, uniform looking coil! Well done!

Please excuse the lack of technical terms used below. I want to try something like that, but I'm wanting to dispense the liquid adhesive (stuff) in a slick fashon.

A small set of pulleys to run the wire right through some liquid "stuff" seems ideal. It also has to be made.

I thought about taking one of those liquid shoe polish dispenser bottles with the foam pad applicator (doohickey) and filling it with something to do what you describe. Placing a metal plate under the fed wire, and above it pushing down is the shoe polish doohickey and it's bottle of "stuff".

A balsaloc soaked paper towel might work.

As for the "stuff", do you think balsarite would also work? I was thinking of trying thinned fingernail polish, but it would most likely dry up pretty quick and clog the foam pad.

One last thing, could you explain the bottom picture. I'm assuming it is the control arm bearing. What does the red represent?
Jul 22, 2004, 04:43 PM
beebe's Avatar

Nicely made coil. I had been using nail polish with decent results, although it tends to stick to the sides of the former if not taken off immediatly. How did you pull the wire through the liquid? A submerged pulley? I might give it a shot.
Good idea with the silicon fuel tubing!
Could you spare me the details of the rest of the actuator? Is that a remote-mount unit?
[edit] Is that red wire insulation an external pivot?

ps Good luck!
Jul 22, 2004, 05:24 PM
Reflex1's Avatar
Nice job!
I'm very new to indoor plane stuff
although Peter and Graham may know me as the micro heli fiend at the Nunthorpe meet

where do you guys find such fine wire ?
Last edited by Reflex1; Jul 22, 2004 at 05:31 PM.
Jul 22, 2004, 09:32 PM
Registered User
phil stevo's Avatar
I like the technique Peter. I also have spent some frustrating time this week winding lots of 200 ohm coils from 0.03 wire, only to break the leads trying to handle them, or solder them either onto stronger wire or into my model. Really need something stronger glued onto coil and to solder leads to.

I have been using PVA glue applied to the mandrel before winding, removing the surplus before it goes off after carefully backing off the side forms washers. I suspect your method puts less glue on the coil though so is probably lighter. I note some others use Ca glue too. Must be other suitable glues. Need to be carefull that glue does not disolve enamel on wire and cause shorting.

Paul: I got my 0.03 approx wire from a 24 hour 240 volt mains timer. There are a few nice gears too. I have made maybe 15 coils so far from this one timer with maybe 30% left. Others are dismantling high Voltage relays.
Jul 23, 2004, 01:22 AM
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peter frostick's Avatar

sticky-wire coils

Hi all: My badly angled photo seems to have confused everyone! so here's a doodle of the primitive test version plus a possible installation method for a model.

Rich: the problem with complex "doohickoid" solutions is the pain of washing everything free of "stuff" afterwards --- the only secret is to apply the minimum quantity of adhesive: If the Balsaloc/Balsarite shows up white on the wire you've used too much!; running the wire over the rounded rim of the glue container helps get most of the surplus off.
Almost any glue that is sold for iron-on films should be OK: ordinary white PVA can be re-activated by heat, but stuff made for the job seems best, and is easily available.

Getting hold of fine wire from dealers in small quantities is seldom possible; obtaining wire by taking relays,timers etc apart is a very good way to get going. G.S. says t's worth giving dealers a call if you don't see the very fine stuff on their lists --- Scientific Wire Co in England stock some suitable wires, but amounts are going to be large!!

One thing I can promise is that micro coil winding can be satisfying: but it will never be fun!!!

Cheers Peter

PS Paul: I always enjoy your "dashing" heli flying
Jul 23, 2004, 06:42 AM
Registered User
peter,great idea to move the pivot out of the coil!
why not making a push pull where the pink arrows are?(90 angle)
Jul 23, 2004, 08:37 AM
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Dave Wulff's Avatar

Beautiful coil. I haven't seen a linkage like that since the escapement days back in the 60's.
As for better terminating wire this idea was around when we first started winding our own coils a couple of years ago, and disappeared with the mass produced coils. Now that pic driven 200 ohm coils are popular I will try to re-describe it. Leave about 6" of extra wire at the beginning of the coil by wraping it around the mandrel. At the end of the wind also leave an extra 6" or so. Push 2 pins in a scrap of balsa about 1" apart. Place this jig next to the coil and wind the wire end around the pins a few times. The idea is to make a short length of litz wire that is intergal with the coil. The wire loops can be removed from the pins with a couple of small music wire hooks. Twirl the hooks in opposite directions to twist the wire, then gently wrap it around the coil so that you can glue about 1/4" onto the outside of the coil. Tin the other end and you will have pretty sturdy leads attached to the coil without soldering. Caution, this is not as easy as it sounds, but when you get it down it works great. If I recall this was told to me by Philip C. from Houston, possibly from Ralph.


PS: Sorry Graham, seeing your post below reminds me that I think you were also doing this type of termination.
Last edited by Dave Wulff; Jul 23, 2004 at 10:31 AM.
Jul 23, 2004, 09:53 AM
Sticky Shepherd
Graham Stabler's Avatar
Scientific wire company sell small 50g spools of most wires they do. As Peter mentioned they have a greater selection than on the website.
Jul 24, 2004, 04:23 PM
Registered User
peter frostick's Avatar
Many thanks for the excellent coil termination advice --- this is by far the worst stage of any micro coil winding job!!! and can be dangerous for the blood pressure!!!!

Jul 25, 2004, 08:10 AM
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Dave Wulff's Avatar

Like I said, it was not my idea, just something I remembered and thought should be reposted with all the recent interest in coil winding. It is not zip-zip, but once you get the hang of it it works well.

Nov 04, 2004, 04:12 PM
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billystiltner's Avatar
That is a neat idea.
Looks like a great way to use 3 magnets as well when 2 will not do and 4 are too heavy.

I think this should be in the index so it doesnt get lost.

Nov 04, 2004, 05:15 PM
Sticky Shepherd
Graham Stabler's Avatar
Your wish is my command but post a request to the index thread if you want to make sure a thread is added, I don't read everything.


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