Can re-stuffing

[Daave]

I have received a whack of new caps for my restoration job, and I have seen lots of pics and whatnot about restuffing the original electrolytic cans, and would like to do that as well. Ive seen 2 ways, one is removing the can and cutting it open, and the other was cutting it off while still on the chassis. But I never understood how you guys were re-attaching the can back together? You have some sort of glue or silicone you are using?

[bob91343]

The can is held together by crimping of the ring. If you are careful you can open the crimp. Removing the old capacitor(s) is not trivial; it can be stubborn and might need to be heated to loosen. Or heating might anchor it even more securely. You may have to dig.

Once the innards have been removed, you can restuff any way you like and then put the crimp ring back on. The object, I guess, is to make the unit look original. You can even make the bottom of the chassis look original if you keep the old fiber wafer. Connecting to the aluminum case is tricky; you probably will have to solder to the crimp ring, which isn't aluminum.

[Daave]

Dayum I can't get enough heat on the ground lugs that attach the can to the chassis without the chassis sinking all of the heat! Even with a 100w iron or a small open flame torch.

[Reece]

I've been able to get them off with a 140 watt gun.

[Phil Nelson]

Unless you're extremely concerned about preserving original appearance, it's not necessary to unsolder the lugs and pull the can off intact.

If you cut it off and pull out the innards, it can be glued back on with JB Weld or a similar epoxy. Some people even use aluminum tape. It depends on how fussy you are about the appearance.

The following article has a section called Replacing Electrolytic Capacitors. It includes links to other articles that show a variety of restuffing methods, with photos and descriptions:

http://antiqueradio.org/recap.htm

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[DaveWM]

if you dont really care about how it looks, My fav way (read fast and easy and uses cheap radial lead caps) is to use a bone saw, cut off just at the shoulder, drill holes for cap leads, put radial lead caps in with neg in center, feed the pos thru and attach to the orig term, some epoxy glue put the can back on, or leave it off.

the reasons for the above are

1) its fast, just cover any holes where you don't want alum chips to go.

2) it keeps all the lead dress orig (but for the single center neg that must be connected to the chassis.

3) its cheap (radial lead caps are MUCH cheaper than axial, and I just dont like to use radial caps under the chassis.

To do a proper job of an under the chassis recap takes a bit of time to figure where you mount term strips, and invites wiring errors.

using the bone saw, I can replace a 3-4 section cap in about 10min tops, and it save having to mess with parts that are soldered to the terminals (like resistors and diodes as an example).

When I fix for others this is the approach I use, since I do not charge for repair work, I want it done a quickly as I can.

[bob91343]

Solder wick may help to remove solder from the ground tabs.

[stusnyder]

Originally Posted by Daave

Dayum I can't get enough heat on the ground lugs that attach the can to the chassis without the chassis sinking all of the heat! Even with a 100w iron or a small open flame torch.

This is the beast I use for chassis soldering, the dollar bill is for size comparison.

[Daave]

Thanks for the info!!

I did (finally) remove the one 4 section cap because it was in a recessed part of the chassis and I couldn't get a good angle on the saw, but I did do one other (and plan to do the rest) by cutting it off in place, right at the base and feeding thru the leads. It worked well! And looks good to me.. I didn't want to put all these big caps underneath and have to reroute wires, etc

Now what does a dried up electrolytic look like? I mean one 4 section vertical cap guts came out real easy (no heat) and it felt dryish but it wasn't crumbling apart. The single filter cap in the power supply on the other hand was very moist and damp and took heat to get the guts pulled out.

This is my first time ever trying this I just watched a bunch of youtube videos

[DaveWM]

great. did you use one of those bone saws i was talking about, they are often sold as a mult tool for cutting in hard to get spots.

[Daave]

Originally Posted by DaveWM

great. did you use one of those bone saws i was talking about, they are often sold as a mult tool for cutting in hard to get spots.

I used a hack saw blade removed from the saw. Its what I had and worked OK.

[DaveWM]

well if you ever come across one of those saws I am describing, you will love it, you can plunge cut straight into the cap. They are not cheap but if you do a low of cans its worth it, IMHO.

[DaveWM]

http://www.google.com/products/catal...ed=0CHUQ8wIwAg

this is it, mine was not cordless.

[stusnyder]

Originally Posted by Daave

Now what does a dried up electrolytic look like? I mean one 4 section vertical cap guts came out real easy (no heat) and it felt dryish but it wasn't crumbling apart. The single filter cap in the power supply on the other hand was very moist and damp and took heat to get the guts pulled out.

They are suppose to be moist and damp. When they are dryed out thats when they fail. I suppose sometimes they are not sealed 100% and eventually dry out.

[Daave]

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