07-19-2006, 10:59 PM
Jun, basically you want to take them apart in such a way that when you put them back they will not look like they were done. With some cans that use a mounting band you can cut them up from the bottom between a 1/2 to 1 inch. The height will depend on where the the band is located. You want to have the cut fall right in the middle of the band so when you remount them the band covers the cut. Having said that, your caps, I believe, are the type that have a base with a protruding threaded bolt which fits through a hole in the chassis and a nut is threaded on which pulls the cap down and snug to the chassis. If you look at the base of the caps you have you will see that the can flares out near the bottom, the base is placed into the flared portion and the sides of the flare are wrapped around and under the base for maybe a little less than a 1/8". You can now visualize that when you tighten that nut on the bottom of the chassis the part of the can now wrapped over the bottom edges of the base are going to be pulled up tight to the chassis making physical and electrical contact with the chassis, your negative lead. The problem you run into in stuffing the caps is providing a contact point to the can. It's aluminum and therefore cannot be soldered (there are method that are claimed to be used to solder to aluminum but I have not done it and I believe it is difficult). I've given the problem with your type caps some thought and believe the following will work:
Grind or file off the 1/8" aluminum that rolls over the sides to the bottom of the base. In other words that portion that is on the bottom of the base, not the sides. This has to be done carefully so as not to damage the base. A little scratching or even small gouges can be tolerated.
With the bottom of can that was rolled over the bottom (which was basically the only thing holding the base up in the can) gone you should be able to twist out the entire base with the contents attached. You may have to play with it a little to get the flange away from the sides but if you take your time and don't force it it will come out.
What you will now have is the base out along with (possibly) some fluid and the rolled foil cap. From the foil cap you will have two leads (not necessarily wire) going to the base. The positive will be attached to the center lead exiting the center of the base. It is usually attached to a rivet which goes all the way through the base and on the outside is another terminal under the other rivet head for wiring into the curcuit of the radio. The rivet holds both terminals together physically and electrically. It could also be a aluminum rod with the foil lead welded to it and on the outside a crimped on terminal made of sheet metal or copper on the rod. Again, these are only two possibilities but they overcome the problem of not being able to solder on aluminum. The negative lead will be attached to the can usually by pressure, not necessarily welded, riveted or bolted. I believe on your type cap the negative lead may be widened at the end and draped over the edge of the base so when the base is pushed into the can it is pressed between the can and the base thus physical and electrical contact is made.
You will now have to remove the rivet and replace it with a 4-40 or 6-32 machine screw and bolt. Both on the outside and inside you place a terminal lug, to the inside one you will later solder the new cap positive, to the outside you will solder the curcuit wire(s). You should use a lock nut or lock washer on the bolt so it will not loosen somewhere down the pike.
The negative terminal presents a problem since you no longer have the metal rolled over the bottom of the base so when you tighten the nut on to the base it would be iffy if the can would come into contact with the chassis. You can use a piece of aluminum flashing (very thin aluminum used in roofing) about a 1/4" wide by an inch long and drill a hole near one end through which you place a bolt with lock nut, you will attach the negative lead of new cap under the bolt (you might want to add a washer). Conform the aluminum strip to the base from the inside, and down the side of the base. leave at least a 1/2" to fold under the base.
Using a 1" long piece of 1" plastic water or electrical pipe cut a 1/2" wide piece out of the pipe down its side. On end it will look like a "C".
Slip the pipe into the upper part of the can leaving a 1/2" exposed. Test fit the pipe/can assembly to the base, the end of the pipe should rest on the base inside the flange. with the pipe still in the can push the can and base together, the flange should fit snugly over the base and the whole assemble should look like the original can. If everything fits take it apart and, using epoxy, cement the end of the pipe to the base making sure that you position it so the can flange will slip over it as it did before. TBC
Grind or file off the 1/8" aluminum that rolls over the sides to the bottom of the base. In other words that portion that is on the bottom of the base, not the sides. This has to be done carefully so as not to damage the base. A little scratching or even small gouges can be tolerated.
With the bottom of can that was rolled over the bottom (which was basically the only thing holding the base up in the can) gone you should be able to twist out the entire base with the contents attached. You may have to play with it a little to get the flange away from the sides but if you take your time and don't force it it will come out.
What you will now have is the base out along with (possibly) some fluid and the rolled foil cap. From the foil cap you will have two leads (not necessarily wire) going to the base. The positive will be attached to the center lead exiting the center of the base. It is usually attached to a rivet which goes all the way through the base and on the outside is another terminal under the other rivet head for wiring into the curcuit of the radio. The rivet holds both terminals together physically and electrically. It could also be a aluminum rod with the foil lead welded to it and on the outside a crimped on terminal made of sheet metal or copper on the rod. Again, these are only two possibilities but they overcome the problem of not being able to solder on aluminum. The negative lead will be attached to the can usually by pressure, not necessarily welded, riveted or bolted. I believe on your type cap the negative lead may be widened at the end and draped over the edge of the base so when the base is pushed into the can it is pressed between the can and the base thus physical and electrical contact is made.
You will now have to remove the rivet and replace it with a 4-40 or 6-32 machine screw and bolt. Both on the outside and inside you place a terminal lug, to the inside one you will later solder the new cap positive, to the outside you will solder the curcuit wire(s). You should use a lock nut or lock washer on the bolt so it will not loosen somewhere down the pike.
The negative terminal presents a problem since you no longer have the metal rolled over the bottom of the base so when you tighten the nut on to the base it would be iffy if the can would come into contact with the chassis. You can use a piece of aluminum flashing (very thin aluminum used in roofing) about a 1/4" wide by an inch long and drill a hole near one end through which you place a bolt with lock nut, you will attach the negative lead of new cap under the bolt (you might want to add a washer). Conform the aluminum strip to the base from the inside, and down the side of the base. leave at least a 1/2" to fold under the base.
Using a 1" long piece of 1" plastic water or electrical pipe cut a 1/2" wide piece out of the pipe down its side. On end it will look like a "C".
Slip the pipe into the upper part of the can leaving a 1/2" exposed. Test fit the pipe/can assembly to the base, the end of the pipe should rest on the base inside the flange. with the pipe still in the can push the can and base together, the flange should fit snugly over the base and the whole assemble should look like the original can. If everything fits take it apart and, using epoxy, cement the end of the pipe to the base making sure that you position it so the can flange will slip over it as it did before. TBC
