Transformer impregnation: paraffin + rosin + natural wax - Page 1
Forum section: electronics / projects

author: 001
author_rank: Super Contributor
timestamp: September 05, 2019, 07:28:25 pm
content: Hi!I rewind vintagesignaltransformerWhat about formula of paraffin + rosin + natural wax compound? Somebody told me 7:2:1Any opinions?

author: ddavidebor
author_rank: Super Contributor
timestamp: September 05, 2019, 07:37:57 pm
content: 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.

author: Gyro
author_rank: Super Contributor
timestamp: September 05, 2019, 07:44:39 pm
content: 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.

author: 001
author_rank: Super Contributor
timestamp: September 05, 2019, 07:47:04 pm
content: Quote from: ddavidebor on September 05, 2019, 07:37:57 pmI 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?Quote from: Gyro on September 05, 2019, 07:44:39 pmHi. It is dodgy technology treadQuote from: Gyro on September 05, 2019, 07:44:39 pmWe free from standarts here. 100% of liberty

author: Gyro
author_rank: Super Contributor
timestamp: September 05, 2019, 08:02:28 pm
content: Quote from: 001 on September 05, 2019, 07:47:04 pmAh, I missed that!Dodgy results to follow.

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: September 06, 2019, 05:53:27 am
content: Quote from: 001 on September 05, 2019, 07:47:04 pmIIRC I have an old book lying around that also involves impregnating transformers. If I remember I try to take a look this evening.QuoteYou do notice, that standardddddds aren't there to cripple your freedom, instead to create a way to unify certain things around the world so that things can be assumed to work here in Germany, in the USofA, in Russia, and also in Antarctica, if done under the same controlled circumstances?What IS crippling your freedom is the politics that enforce the application of some standards influencing the things you do.

author: 001
author_rank: Super Contributor
timestamp: September 06, 2019, 12:40:23 pm
content: it is signal transformer of some audio gearwax increase bobbin capasitance and it adds "authentic" feeling

author: Gyro
author_rank: Super Contributor
timestamp: September 06, 2019, 04:31:21 pm
content: Quote from: 001 on September 06, 2019, 12:40:23 pmWell you could have mentionedthatearlier.

author: 001
author_rank: Super Contributor
timestamp: September 06, 2019, 07:15:16 pm
content: Quote from: Gyro on September 06, 2019, 04:31:21 pmAny info of mid-1960s impregnation technologies?

author: Bud
author_rank: Super Contributor
timestamp: September 06, 2019, 07:53:22 pm
content: Quote from: 001 on September 06, 2019, 12:40:23 pmAuthentic feeling to the sound?

author: Gyro
author_rank: Super Contributor
timestamp: September 06, 2019, 07:58:11 pm
content: 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 expectanyimpregnant 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.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: September 06, 2019, 11:30:15 pm
content: 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.

author: vk6zgo
author_rank: Super Contributor
timestamp: September 07, 2019, 02:34:04 am
content: 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.

author: Gyro
author_rank: Super Contributor
timestamp: September 07, 2019, 09:32:15 am
content: 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.

author: 001
author_rank: Super Contributor
timestamp: September 07, 2019, 10:58:35 am
content: Quote from: Gyro on September 07, 2019, 09:32:15 amIt is transformer in grid circuit of vacuum tube 1:20I see similar wax-look transformers in common tube radios 40 year agoQuote from: Bud on September 06, 2019, 07:53:22 pmWhy not? It is customer demand so I must make it as described. Lets customers be happy

author: tooki
author_rank: Super Contributor
timestamp: September 09, 2019, 01:35:26 am
content: Quote from: ddavidebor on September 05, 2019, 07:37:57 pmNo, 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 toa museumSaturday 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.

author: cjenrick
author_rank: Newbie
timestamp: October 20, 2019, 07:48:07 pm
content: this is the bible on insulation right here>https://www.electrostatic.com/bookstore/books/shugg.htmhere is a site with transformer winding info>https://vacuumbrain.uk/