Best way to stuff capacitor ?

[tim.54]

Have removed the chassis from the marconi 556 , about to swop the capacitors , each capacitor has its own metal recess in which it sits acting as a support for other attached components , so will need to restuff them .The 0.1 uf ones are quite large 2.5inch by 1 inch ! looks to be a tar like substance in each end , best way to remove and what to refill with , all advice welcomed , regards, tim.

[Nick]

I would solder a some flex to the tabs and anchor the other end in a vice or similar.

Then use a heat gun (maybe a hair-dryer would be hot enough?) to heat all round the paper, rotating to get even coverage.

As the tar softens, gently pull out the contents via the flex on the tabs..

[tim.54]

good idea Nick , will wait till the wife goes out to give it a try , (i don`t need a hair dryer these days!)
regards, tim.

[Radio Fixer]

You may find it difficult to remove without breaking up the tube. It depends if it is just weak cardboard. But you can make a replica from a piece of plastic pipe (I buy styrene tube from my local model shop) and cover it with brown paper. Can do a print job from the PC if you like for the lettering. I use brown envelopes for this but be sure to print on the smooth side. To give an aged look then rub over with French Polish.

For filling a hot melt glue gun is quick and easy and you can paint over this with oil based model paints. If you don't have a glue gun then epoxy, coloured with a little drinking chocolate, looks OK. Of course you will have built out the new cap with tissue or masking tape etc so you don't need too much.

You can see some of my replica caps here (one with red and green bands on):
http://golbornevintageradio.co.uk/forum/...p?tid=4153

I doubt a hair dryer will do the trick: heat gun for me.

Gary

[Refugee]

I have used a little heated pot for melting wax off capacitors.
The resistor that is acting as a heating element is a 47R 25W aluminum clad type running from 24 to 30 volts.
You could run it from a 24 volt soldering station if need be. I just used a 30V bench power supply for mine.
The pot is an old film canister but there are one or two pill pots that have a screw top to be found for this purpose.

[AlanBeckett]

That's a splendid setup, especialy the bracketry.
I've kept some old Wax and I've been collecting Cardboard Tubes if any are of use.

Alan

[Yorkie]

I don't often re-stuff caps, but made an exception with a pre-war Ekco AC77 that I'm slooowly restoring. I find that two-part epoxy 'Plastic Metal' - a product by Plastic Padding makes a nice job of sealing the ends - it looks just like pitch when set. Despite its name, it isn't metal and is non-conductive. There is more info and some pics at post 15 at this link:

http://golbornevintageradio.co.uk/forum/...p?tid=3709

Hope that helps a bit Tim.

Good luck with your restoration efforts!

[Radio Fixer]

On the caps that I provided a link to the brown paper is actually gummed paper parcel tape that we used to use years ago, before the Mylar stuff. If you can find any its quick and easy.

As others have demonstrated hopefully you can push the old paper and foil out with heat and a screwdriver, or as Nick suggested by soldering on some wires and grabbing those in a vice. Hold the hot cap in a gloved hand of course.

If you have a hot melt glue gun it has one advantage in that a hot air gun can be used in the future to remove the contents again.

Gary

[Nick]

Always wondered this - is the wax on these old paper caps just pure bees wax, paraffin wax, or something more subtle?

If it's bees wax, I've kilos of that!

[tim.54]

Thanks for everyones input , have extracted the innards , what do you think re using black silicone sealant to seal the ends once the capacitor is fitted ?
regards, tim.