Author Topic: Transformer impregnation: paraffin + rosin + natural wax  (Read 3764 times)

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Offline 001Topic starter

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Transformer impregnation: paraffin + rosin + natural wax
« on: September 05, 2019, 07:28:25 pm »
Hi!

I rewind vintage signal transformer
What about formula of paraffin + rosin + natural wax compound? Somebody told me 7:2:1
Any opinions?  :-//
« Last Edit: September 06, 2019, 07:16:03 pm by 001 »
 

Offline ddavidebor

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #1 on: September 05, 2019, 07:37:57 pm »
I don't know about vintage transformers but I know about cosmetic formulation.
You can buy paraffin in different molecular weight (from oil viscosity to hard wax) and mix it to obtain the properties you prefer.
Rosin was probably because it behaves like a flux.

There is no point in having precise paraffin/wax ratio as the end result depends on the molecular weight.
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Offline Gyro

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #2 on: September 05, 2019, 07:44:39 pm »
If rewinding a vintage transformer, I would still use modern high temperature formulations, ie. Polyurethane.

After all, you can't reuse the original wire or degraded insulation and you need to bring it up to current safety standards.
Best Regards, Chris
 

Offline 001Topic starter

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #3 on: September 05, 2019, 07:47:04 pm »

Rosin was probably because it behaves like a flux.

There is no point in having precise paraffin/wax ratio as the end result depends on the molecular weight.

I think what rosin increase solidus temperature of clean paraffine. But what about wax? Is it for wetting reason?

Does anybody know some vintage articles about DIY transformers?


If rewinding a vintage transformer, I would still use modern high temperature formulations, ie. Polyurethane.
Hi. It is dodgy technology tread  :-+

  you need to bring it up to current safety standards.
We free from standarts here. 100% of liberty
« Last Edit: September 05, 2019, 07:52:35 pm by 001 »
 

Offline Gyro

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #4 on: September 05, 2019, 08:02:28 pm »
Hi. It is dodgy technology tread  :-+

Ah, I missed that!  :)

Dodgy results to follow.
Best Regards, Chris
 
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Offline Ysjoelfir

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #5 on: September 06, 2019, 05:53:27 am »
Does anybody know some vintage articles about DIY transformers?
IIRC I have an old book lying around that also involves impregnating transformers. If I remember I try to take a look this evening.

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What IS crippling your freedom is the politics that enforce the application of some standards influencing the things you do.
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Offline 001Topic starter

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #6 on: September 06, 2019, 12:40:23 pm »
it is signal transformer of some audio gear
wax increase bobbin capasitance and   it adds "authentic" feeling
« Last Edit: September 06, 2019, 07:16:32 pm by 001 »
 

Offline Gyro

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #7 on: September 06, 2019, 04:31:21 pm »
it is signal transformer of some audio gear
wax increase bobbin capasitance and adds it adds "authentic" feeling

Well you could have mentioned that earlier.  ::)
Best Regards, Chris
 

Offline 001Topic starter

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #8 on: September 06, 2019, 07:15:16 pm »
it is signal transformer of some audio gear
wax increase bobbin capasitance and adds it adds "authentic" feeling

Well you could have mentioned that earlier.  ::)

Any info of mid-1960s impregnation technologies?
 

Offline Bud

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #9 on: September 06, 2019, 07:53:22 pm »
it is signal transformer of some audio gear
wax increase bobbin capasitance and   it adds "authentic" feeling
Authentic feeling to the sound?  :-DD
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Offline Gyro

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #10 on: September 06, 2019, 07:58:11 pm »
Well if it's a signal transformer that's not dissipating power and not in a hot environment, then the simpler the better. I remember plenty of '60s stuff using simple wax, eg. Candle wax.

If you want decent impregnation without a vacuum chamber then you need something with a low enough melting point that you can safely immerse and heat the transformer to allow air to naturally bubble out of the windings. Wax (heated in a water bath) seems to fit the bill.


P.S. I wouldn't expect any impregnant to have a significant enough impedance to affect the 'feeling' at audio frequencies but it would at least be soft enough to damp any winding / core vibrations if that's what you mean.
« Last Edit: September 06, 2019, 08:06:32 pm by Gyro »
Best Regards, Chris
 

Offline Conrad Hoffman

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #11 on: September 06, 2019, 11:30:15 pm »
The transformer may not get hot on its own, but don't forget the total environment. I think they were using varnish in the '60s, at least for better stuff. Probably have to go earlier to find wax, though I've seen a few telephone coupling transformers with wax or something similar.
 

Offline vk6zgo

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #12 on: September 07, 2019, 02:34:04 am »
It makes a bit more sense, being for an audio transformer, as, apart from standard "Telephone company" types, which were made in the millions, (& were not wax coated), full sized audio transformers were made in much smaller numbers than power transformers, so may well have used such techniques.

I have seen, used, & messed about with, power transformers from late 1920s units to present day types, & I can't recall any using wax coatings.

Power transformer manufacture is a mature technology, & the insulating materials & varnishes they used back in the 1940s, '50s, & '60s were more than capable of,doing the job they were used for.

Most of the failures I have seen were open circuit windings, or windings with shorted turns.
These are usually from severe overload, which would cook any modern transformer equally badly.
 

Offline Gyro

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #13 on: September 07, 2019, 09:32:15 am »
There's clearly a lot of overlap - I've certainly seen wax used in IF and output transformers (and to damp microphonics in the FM coils) in '70s transistor radios.

I guess it depends what the OP means by a signal transformer (and as you say, Conrad, the temperature of the overall environment).

I'm not sure if varnish automatically means vacuum impregnation? It certainly seems to be the case with modern polyurethane types.
Best Regards, Chris
 

Offline 001Topic starter

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #14 on: September 07, 2019, 10:58:35 am »

I guess it depends what the OP means by a signal transformer (and as you say, Conrad, the temperature of the overall environment).

It is transformer in grid circuit of vacuum tube 1:20
I see similar wax-look transformers in common tube radios 40 year ago


it is signal transformer of some audio gear
wax increase bobbin capasitance and   it adds "authentic" feeling
Authentic feeling to the sound?  :-DD
Why not? It is customer demand so I must make it as described. Lets customers be happy  :-+
 

Offline tooki

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #15 on: September 09, 2019, 01:35:26 am »
Rosin was probably because it behaves like a flux.
No, rosin is used in a lot of “waxes” to provide hardness and toughness. For example, the sealing wax used for wax seals was actually mostly rosin and shellac, because actual wax isn’t strong enough. I’m pretty sure rosin also improves the hygroscopic and thermal properties of beeswax.

By pure chance I went to a museum Saturday night about wax dermatological pathology models, and they shared the once-secret recipe, which is a blend of beeswax, calcium carbonate, and dammar gum (which is a resin somewhat similar to rosin). And indeed, that is hard wax, very unlike pure beeswax.
 
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Offline cjenrick

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Re: Transformer impregnation: paraffin + rosin + natural wax
« Reply #16 on: October 20, 2019, 07:48:07 pm »
this is the bible on insulation right here>

https://www.electrostatic.com/bookstore/books/shugg.htm

here is a site with transformer winding info>

https://vacuumbrain.uk/
 
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