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Re: FW: Unpotting a France 12/30

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Jim,
I would recommend removing the tranny from the case. You'll likely do more damage trying to remove shunts with it in the case than simply lifting the transformer out of the case. I don't know what the big deal is? I wouldn't drill the case. That is unnecessary. Desolder the two GTO cables and the core to case wire and lift the tranny out of the case. It's much easier to clean and remove shunts on a workbench. After you remove the shunts, you will want to add in a spacer to keep the shunts nice and tight. Then plop it back down in the case and resolder the wire connections. I recommend keeping half the shunts in (just count them). Your already 80% of the way completed. The real task ass removing the tar and you've already jumped that hurdle. Removal and installation of the tranny is the easy part.
I used gasoline myself (excellent for cleaning, but remember, it is gasoline). My father was a mechanic, so I was bathed in gasoline every day. That's how we cleaned everything. I have noticed that my hands are far more sensitive to gasoline than they use to be. So, I try to keep my hands out of it as much as possible and let hand tools (brushes, etc.) do the work. If you do use gasoline, keep in mind that sparks are a bad idea, so don't get crazy with metal to metal friction. Use a nylon brush designed for this type of solvent. It's sold in most autoparts stores (looks like a supersized paint brush with much thicker bristles). 

Take care,
Bart

Tesla list wrote:


Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Hello List,
I searched the archives and read Richard Quick?s methods. Generally he did not recommend trying to unpot a neon in the case as the transformer is not attached to it and the wires get broken. Hmm, I easily chipped off the asphalt off the top of the transformer. Then I took an 8? C clamp and thread side up clamped the transformer in place. This makes for a handy handle. I then fired up the barbeque. I had to set it in the lava stone to close the cover. In the time it takes to slow cook a thick steak, I had all the asphalt melted and drained out, no wires disturbed. It is now marinating in Diesel fuel. The trick will be to remove some shunts while in the case, mayhap I will have to drill a couple of holes through the side and then plug them??? 

Regards,
Jim Mora


----------
From: Jim Mora [mailto:jmora@xxxxxxxxxxx]
Sent: Monday, February 26, 2007 6:43 PM
To: 'Tesla list'
Subject: Unpotting a France 12/30

Hello,
I have a couple of France 12/30?s. I want to un-pot one of them (some of the tar is cracked and likely leaky) and remove a few shunts to make a cap charger with a 5x multiplier. A newer 15/60 works just fine with some serious humming­ fast and weighs three times the France! I am wondering if I can keep the France in the original tank and carefully heat it in a gas powered BBQ. Ideally, I would like to pour molten tar out and soak the tranny in diesel, or gasoline to dissolve the rest. I guess I will have to remove the core to knock out some shunts and hopefully be able to reconnect the HV bushings.
If I can leave it in the original tank, I would melt some paraffin and Vaseline together and repot it in that. Hopefully I can squeeze 40 or 50 ma out of it and current limit the cap input which would likely be just right. I know this is a well covered thread; but, has anyone successfully done this using a similar method? I would be open to mineral oil which probably sinks away the heat better, but the on time should be no more than a couple minutes. 

Thanks Much,
Jim Mora