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Old 29th Nov 2021, 7:01 pm   #1
pentoad
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Default Hard wax on RF coil ferrite slugs

Could Otex ear drops dissolve the hardened wax which prevents the fragile slugs from rotating?
The active ingredient is urea hydrogen peroxide (5% w/w). The other ingredients are 8-hydroxyquinoline and glycerol
Not sure if this could damage the coil former.
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Old 29th Nov 2021, 7:53 pm   #2
Goldieoldie
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Default Re: Hard wax on RF coil ferrite slugs

If you heat the slug with a soldering iron just enough to soften the wax I find that works ok
Cheers
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Old 30th Nov 2021, 6:01 pm   #3
pentoad
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Default Re: Hard wax on RF coil ferrite slugs

Quote:
Originally Posted by Goldieoldie View Post
If you heat the slug with a soldering iron just enough to soften the wax I find that works ok
Cheers
Pete
I have tried that but it did not work, it's still stuck that's why I'm considering Otex.
It might be damaged or cracked it's difficult to tell but the radio (Phiips 310A) is functional now, I'm not sure if it can be improved upon.
I may well leave it as it is.
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Old 30th Nov 2021, 7:06 pm   #4
Bazz4CQJ
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Default Re: Hard wax on RF coil ferrite slugs

As a chemist, my instinct is that Otex is not the way to go, but I could be wrong. Are you really sure the stuff is wax and not something else like paint? Waxes tend to have 'modest' melting points.

Can you offer some more details on the formers? Are we talking IF coils, are they plastic or something else, what era are they. As you say, any approach needs to avoid damage to the formers.

Wickes do a paint and varnish remover which I have used successfully to soften various substances with (in the process of cleaning), and I suspect it would soften (real) wax, but I know that it does react with some plastics.

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Old 30th Nov 2021, 7:37 pm   #5
pentoad
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Default Re: Hard wax on RF coil ferrite slugs

Quote:
Originally Posted by Bazz4CQJ View Post
As a chemist, my instinct is that Otex is not the way to go, but I could be wrong. Are you really sure the stuff is wax and not something else like paint? Waxes tend to have 'modest' melting points.

Can you offer some more details on the formers? Are we talking IF coils, are they plastic or something else, what era are they. As you say, any approach needs to avoid damage to the formers.

Wickes do a paint and varnish remover which I have used successfully to soften various substances with (in the process of cleaning), and I suspect it would soften (real) wax, but I know that it does react with some plastics.

B
Philips 310A 1952 S14 coil slug
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Old 30th Nov 2021, 7:57 pm   #6
Bazz4CQJ
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Default Re: Hard wax on RF coil ferrite slugs

Why don't you get a sharp knife and lift of some of the excess wax which is on top of the can and experiment with it? If it doesn't melt at some reasonable temperature (<100'C), that would be off-putting, tending to suggest it is a material which has set and may need a strong solvent to soften it.

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Old 30th Nov 2021, 7:58 pm   #7
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Default Re: Hard wax on RF coil ferrite slugs

Never mind moving the stuck slug.
Add another ferrite slug and see if you can peak the coil. Leave it in if that works.
If the output goes down there is a need to reduce the inductance. Introduce a small piece of brass or aluminium rod into the former and see if it peaks, glue that in if it does.
If nothing peaks the coil then the existing slug is in exactly the right place.

This may not work with TV IF coils where the core affects coupling.
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Old 30th Nov 2021, 8:02 pm   #8
Bazz4CQJ
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Default Re: Hard wax on RF coil ferrite slugs

Curious that on the two transformers to the right, the slugs seem to be on brass screw shafts, but the coil that's highlighted is different.

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Old 30th Nov 2021, 8:53 pm   #9
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Default Re: Hard wax on RF coil ferrite slugs

Further to reply from John (Sundog) "back in the day" there was a device like a pencil called a Tuning Wand which had exactly what he described ie a ferrite slug at one end and a brass slug at the other.
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Old 2nd Dec 2021, 12:24 pm   #10
pentoad
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Default Re: Hard wax on RF coil ferrite slugs

Quote:
Originally Posted by Sundog- View Post
Never mind moving the stuck slug.
Add another ferrite slug and see if you can peak the coil. Leave it in if that works.
If the output goes down there is a need to reduce the inductance. Introduce a small piece of brass or aluminium rod into the former and see if it peaks, glue that in if it does.
If nothing peaks the coil then the existing slug is in exactly the right place.

This may not work with TV IF coils where the core affects coupling.
I will try that, now I need to find some bits!
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