separating varnished laminations

[talonix]

Got a motor rewind shop nearby? We used one for European tube OP transformers - mostly Grundig, Nordmende and TFK stuff. After the lamination removal and core recovery by the motor rewind guys, we rewound the transformers core on an old Meyer (Mayer? - been too long...) coil winder. A fly-fishing supply place yielded the fiber tape for wrapping each successive coil. We used purple, just like some of the originals.

I dunno what they used to remove the laminations - but the transformer went back to them for the dip and vacuum varnish. $18 a transformer total, or 3 for $30, and this was in the early-mid 80s. Your experience today will probably be different.

I have one Telefunken OP transformer with newspaper stuck to one side after the vacuum varnish. The article refers to the "upcoming 1984 US Presidential election".... Yeah, that far back..

 

[Osvaldo de Banfield]

My de-varnishing set.

Here is my set, and 4 cores cleaned. A couple of days inside the glass can, and the varnish vanishes...

 

[lexx21]

Well, I just dropped a transformer into a bath of paint thinner ans methyl ethyl ketone. Will report back in a week or so and give a report....

Still looking for a good source of chloroform...from what Banfield has shown, that stuff is the heat when it comes to freeing up laminations.

 

[wrenchone]

MEK probably won't do much good, Methylene chloride or chloroform are the way to go.

 

[lexx21]

Its actually half mek and half paint thinner. Im figuring that it wont work and I did find chloroform. Its 55usd for 32oz. Looking for cheaper sources but if necessary then I will buy it from that source.

 

[lexx21]

It is working. Not really sure just how impregnated it is, but I am going to leave it in to soak until the weekend as that will be the soonest that I will have time to mess with it again.

 

[lexx21]

Well, I couldn' wait....I started pulling out the "I" pieces. I will finish it up tomorrow. The solution worked really well, it just stinks to high heaven....lol

 

[lexx21]

Success! One transformer complete and the next one is in to soak.

It came apart pretty easily after I remembered there was a shim between the bobbin and the core....DOH!....I removed it first before dropping the second transformer in the bath.

 

[richie00boy]

Glad it worked for you. That's what we used to do at the transformer factory I had a summer job at.