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Old 6th October 2011, 11:58 AM   #1
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Default Transformer potting material? what material?

I want to pot some opt's that i got, in boxes, but i don't know what material to use. it needs to be something that conducts heat easely.
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Old 6th October 2011, 12:18 PM   #2
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Why do you want to enclose the OT in a box ?
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Old 6th October 2011, 12:38 PM   #3
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Why not? I will reduce the chances of vibrations, i can insert shielding in the potting material, etc....
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Old 6th October 2011, 01:28 PM   #4
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Just checking if you had specific needs, eg. due to existing problems such as vibrating laminations or windings, or stray field causing feedback into sensitive stages, or ugly looks, or safety concerns from touching wiring or insulation, or ?

Is the transformer vacuum impregnated already, or just a dry build?
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Old 6th October 2011, 02:41 PM   #5
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Quote:
Originally Posted by trobbins View Post
Just checking if you had specific needs, eg. due to existing problems such as vibrating laminations or windings, or stray field causing feedback into sensitive stages, or ugly looks, or safety concerns from touching wiring or insulation, or ?

Is the transformer vacuum impregnated already, or just a dry build?
They are not, and i dont want that. i want the material around the transformer.
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Old 6th October 2011, 03:05 PM   #6
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The material generally (always) used by professionals is Epoxy. I think there is little point in not having the Transformer vacuum impregnated. The epoxy potting is used to suppress vibrations in the windings and laminated core , so it has to penetrate the fine interleaves to be efficient.
presumably it also helps with heat resistance / transfer capability (not sure how it does, but I was told so when visiting one of my customers factory (they make high power generators).

I'm not sure where to buy the "Transformer specific" Epoxy, but a pot of standard bi-compound Epoxy glue would probably do the trick if you're not after a very optimised potting...
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Old 6th October 2011, 03:18 PM   #7
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Quote:
Originally Posted by Lazybutt View Post
The material generally (always) used by professionals is Epoxy. I think there is little point in not having the Transformer vacuum impregnated. The epoxy potting is used to suppress vibrations in the windings and laminated core , so it has to penetrate the fine interleaves to be efficient.
presumably it also helps with heat resistance / transfer capability (not sure how it does, but I was told so when visiting one of my customers factory (they make high power generators).

I'm not sure where to buy the "Transformer specific" Epoxy, but a pot of standard bi-compound Epoxy glue would probably do the trick if you're not after a very optimised potting...
Most of this is nonsense...

I don't use epoxy based potting compounds or impregnation resins anymore because I found out to be allergic for epoxy; there are equally well functioning alternatives based on polyyrethane.

Epoxy potting is not used for impregnating windings and laminations; it does not have the right viscosity to do that; you must use resins to do that job.

Not vacuum impregnating audio transformers makes sense as vacuum impregnating will cause more capacitance and that is what we don't need here. Air is the best dielectricum as long as we don't put our transformers in vacuum.
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Old 6th October 2011, 03:24 PM   #8
Bone is offline Bone  United Kingdom
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Many early transformers were dipped in Hot paraffin wax. Why not try that? Keep it in until the air bubbles stop!
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Old 6th October 2011, 03:27 PM   #9
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Digikey sells potting compound.....it's thermally conductive epoxy

Digi-Key - 473-1089-ND (Manufacturer - 832TC-450ML)

Looks like it's about 10 cents/ml

After searching for another 30 seconds, it appears that Mouser sells many varieties of potting compound also.

Mouser Electronics - Electronic Component Distributor potting compound
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Old 6th October 2011, 03:28 PM   #10
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Quote:
Originally Posted by Bone View Post
Many early transformers were dipped in Hot paraffin wax. Why not try that? Keep it in until the air bubbles stop!
Yes, that is a good DIY option for audio transformers which does not get that hot to cause the paraffine melt.
Just buy some big cheap candles....
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