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RESCUING PULSE CAPACITORS

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LAN_403

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Sat Mar 23 2019, 08:24PM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

Sounds great, THANKS!! You may have missed the "EDIT" I added, so I will add it on here again now:

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EDIT:
@MRMILSTAR:
Maybe i can get the caps dry (when upside down), apply the-JB Weld, make sure I see no moisture leaks when turned upright, and THEN if no leaks appear, apply the Rustoleum primer (let primer dry) and then the paint??
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BTW: I have NEVER used rustoleum before this!

MRMILSTAR

Sat Mar 23 2019, 09:22PM

Registered Member #62119 Joined: Sun Feb 04 2018, 04:59AM
Location: Cedar Rapids, Iowa
Posts: 136

Sounds like a good plan. I did miss the edit. I don't think that there is anything special about Rustoleum. I just know that it is a good quality spray paint. I am certain there are other brands equally as good.

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Sat Mar 23 2019, 11:10PM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

OK, I will follow this plan (JB-Weld, rustoleum primer/paint, and time). If anyone has any suggestions to add to it, take away from it, or modify the plan, please let me know. It will be a couple of days because of the other mess of very slippery, rusted caps (which are now just placed upside down in a box).
I should get to the first 'minor damaged' cap sooner. and post the results.

And YES, all the other oil-filled caps which did not have this kind of outer plastic construction seemed to dry out with no problems! This is certainly NOT a good way of enhancing insulation. I will try to think of an alternative.

johnf

Sun Mar 24 2019, 01:33AM

Registered Member #230 Joined: Tue Feb 21 2006, 08:01PM
Location: Gracefield lower Hutt
Posts: 284

What you can not solder because of the oil
I have soldered many high voltage caps (plastic capacitors Inc and Maxwell pulse jobs, plus a few no name copies) to stop leaks favoured weapon is a pace soldering station with a BIG chisel bit with solder station set to 8 as hot as will go -killed spirits of salts as flux and 0.125 solder . I prefer this solution as the solder can not rust so the fix is permanent.

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Sun Mar 24 2019, 10:55AM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

@johnf,
I am not sure of the soldering station wattage and tips you are speaking of. Can you give more information such as temperature, more specific tip size, etc. The largest iron I have is 60W. My two 325W guns were destroyed.

johnf

Sun Mar 24 2019, 06:39PM

Registered Member #230 Joined: Tue Feb 21 2006, 08:01PM
Location: Gracefield lower Hutt
Posts: 284

Pace Sensatemp PS90 I presume the 90 is watts
set to 850F approx 450C
Be ye warned that using killed spirits of salts does eat up soldering iron tips but a $10 tip is worth rescuing a rare expensive capacitor

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Sun Apr 07 2019, 03:22PM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

Thanks all.
BTW, Did I mention that there were three sizes of caps that I called small, medium, and large, + one 300lb pole pig?

I tilted over the large ones and it looked like I better treat then too! So I have some supplies and will get to work. There are 98 smalls, 10 mediums, and about 10 large caps--I sure don't want to lose them. I did manage to get the drone caps up high in time!!!

I just may be able to save then all, THANKS TO YOU GUYS!!! One more thing: I have a lot (~75) MOTs that need help...perhaps just a good heating (with tar or paraffin) will help? I do think the paraffin will go even with no load though! My favorite of the small xfmrs is a modified (15kV @ 60mA) NST from which I de-tarred and removed some shunts...got 25kVDC @ 70+mA from it, with the help of a hefty variac and a FWB.

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Fri May 03 2019, 05:43AM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

Hi all,
I will be finished with the capacitor repair process (WHAT A LOT OF WORK!) by the end of the weekend. I will post the results when all primer+paint (rustoleum) has set, the final capacitance is measured, and they are determined to be leak-proof. The last dozen were done with rustoleum primer two coats of 'flex-seal'. The rest with three coats of primer + two coats paint (all rust-oleum).

I had about 100 caps, however, two of them were so rusted (they were left outdoors for months) that they looked un-fixable. So I threw them out. Most were 196uF @ 2300Vdc and 115uF # 2300Vdc. I did find one 50uF in the bunch.

They look sonething like this:

(I hope that came out)

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Sun Jul 07 2019, 07:08PM

Registered Member #54278 Joined: Sat Jan 17 2015, 04:42AM
Location: Amite, La.
Posts: 367

In over 100 leaking caps, most leaked through non-obvious ways. Some through visible holes at the bottom corners--especially when squeezed. The latter, I used J-B weld, and ALL with the bottoms 3/4" with rustoleum. 4-coats primer + 2-coats paint. Used a bit of 'flex-seal on a couple, maybe overkill, but in over 3 months and NO LEAKS! Many used! THANKS GUYS!!!!

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