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 Post subject: Restuff Micamold Capacitors?
PostPosted: Jun Thu 28, 2012 3:53 am 
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Location: Rogers AR
Has anyone tried to do this? I have a radio that has several under the chassis. Since I am going through the trouble of restuffing the other capacitors present, I would like to do the same for these.


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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jun Thu 28, 2012 4:24 am 
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I wouldn't bother.

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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jun Thu 28, 2012 4:39 am 
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Depends on what the radio is, I suppose.

I have done it. Dremel tool with cut-off wheel to open them. Was able to find some small flat modern film capacitors on eBay that fit inside, and hot glued them back together.

I wouldn't bother doing it on a BC-348 receiver, because they are so common, but sometimes there are some rare things which maybe might be worth the effort.

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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jun Thu 28, 2012 6:10 am 
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Only for a museum quality restoration. Anyway they will be the first thing torn out by the next restorer.


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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jun Thu 28, 2012 8:01 am 
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Someone on here once had a really good pictorial of how to do it. I suspect they were lost with many other of the photo links when the system was moved. I saved them and would be glad to send them to you if you will send me a PM with an email address. Here was what he ended up with after stuffing with a small silver mica if you cannot get a small enough film cap.

I think it is worth doing, but my obsession with restuffing has always made me the odd-man-out on here.


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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jun Thu 28, 2012 1:09 pm 
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It's doable, but it could be easier to take a two-part mold of the old case using the Alumilite process, and just mold new cases around new capacitors.

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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jul Sun 08, 2012 3:07 pm 
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I like that Alumilite idea. I have used that on other projects, and was impressed with the results.


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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jul Mon 09, 2012 7:02 am 
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Hi Ron,
Those were my shots of the restuff. I only did the one cap, just to see if it can be done, but have not done any since. Some folks might not care, but I wanted to see if it could be done.
There was discussion if the JB Weld would be conductive. Might be better to use regular epoxy.
I think this was a line bypass cap, but the other smaller valued caps could be done the same way.

Yep, they probably got lost in the Gallery images when the site was revamped. Here they are again.
I'm glad someone saved those shots besides myself. :)
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mc8.jpg
mc8.jpg [ 26.24 KiB | Viewed 1507 times ]

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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jul Mon 09, 2012 7:15 am 
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JB Weld is not conductive, which is kind of surprising, and I have hi-potted some up to somewhat over 1 KV. But...it does contain little flecks of steel powder, which makes no sense to me as I don't see how that would have any useful function as far as what it is. The stuff is getting so expensive that I started using just a hot glue gun instead. I save the JB Weld to patch holes in cabinets that have Black & Decker Disease.

I have also used the 2-part clear epoxy that comes in the syringe thing. That stuff hi-pots out to well over 45 KV and I have used it to fix TV flyback transformers. It's also cheaper than JB Weld.

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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jul Mon 09, 2012 12:31 pm 
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Thanks for posting the pics again. I have pondered doing this but figure they will just be snipped out by the next hack budding restorer that follows the practice of just snipping and tossing all micamolds.

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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jul Mon 09, 2012 7:05 pm 
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Hi,
I will usually put a small label under the chassis stating that all the caps were replaced/restuffed, on such and such a date. Not just for Micamolds, but maily the paper ones. As I said, I have not restuffed another one of these since, but if I ever wanted to, I know it can be done.
Original caps with Zenith or Philco on them I will usually restuff, unless it's a really cheap AA5 or the owner doesn't

Sure, someone might still clip them out. If the set isn;t mine anymore, I don't care. Another restorer might see the set was recapped only a year back and would leave them alone.
The project was fun in any case :)
Take care,

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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jul Mon 09, 2012 7:42 pm 
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Gary, those pictures are great! I've been wondering how that was done. Thank you!!

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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jul Mon 09, 2012 8:15 pm 
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It is far easier to buy a modeler's molding kit and recast the shells.
Just add a modern silver mica cap inside before pouring the resin into the mold.
Once the resin sets, use Kestor's paint to finish the job.

http://shop.hobbylobby.com/products/alu ... it-579714/

Pete

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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jul Mon 09, 2012 8:30 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Gainesville, Florida
that is pretty cool. although I am looking at radios that look cool on the outside. unfortunately I have never been asked to to take the chassis out and show the underside or topside of the chassis for that matter. no one has even asked to look at the back to see whats in there. boo-hoo. I would like to say 'hey do you want to see the chassis' but might get mixed reactions. I have been meaning to try this but I look at an old capacitor and ask myself 'do I really want to do this'. its always been no so far. but I do have a pot full of these relics to bring back to glory one day. I do appreciate the art of it all. the craft. some day I too will be an old stuffer


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 Post subject: Re: Restuff Micamold Capacitors?
PostPosted: Jul Mon 09, 2012 8:57 pm 
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Hey Gary,
Glad to see that series of photos resurrected. If I happen to run across any mica caps that do need to be replaced, I might just try the molding idea though to see how that works. If so, I will use the epoxy putty method that Syl used for dogbone resistors. I've done several of those and had no problems at all with overheating or worries about shorting. Your method still seems best for some of those larger caps with sharp, square edges.

P.S. If Micamold had just stayed with their eponymous product, we would probably not be having some of these conversations. I have found no higher failure rate with their micas than anyone else's. It is only their resistors and paper caps that look like micas that seem to be the problem.

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