02-10-2013, 09:58 PM
Ron's thread with the Philco Tropic reminded me of something I have been working with lately, the post showing the filter caps. I've been contemplating ways to restuff twist lock electrolytic cans myself, mainly for a vintage TV project. One way would be to use a pipe cutter and cut the can somewhere above the bottom, maybe 3/4 of an inch up, heat up the can, and then pull the contents out with a corkscrew or a deck screw. But then you need to find something to couple the two sections together which is not always easy.
I had to do this with a pair of filter cans in my Rogers Ten-60, it had a pair of dry electrolytics where someone crudely cut each can in half with a hacksaw and then attempted to glue them back together with contact cement. I took them apart, cleaned off the goo, and then wrapped each section with a band of masking tape, then filed down almost to the tape line, then honed each edge perfectly flat on a piece of 600 grit sandpaper on a chunk of granite. I got lucky with the first can, the outside diameter of a 3/4 inch PVC pipe coupling almost fit perfectly, a little bit of hot glue and it was back together, the second can is larger so I will likely need to make a coupling by turning down something slightly larger.
I think the method Sylvian used would be the best, cut or pop the cap off the top and use something like that orange juice cap to couple it back together. I only did it this way because I had no choice if I wanted to salvage the old cans, some prior repairman made the decision which method I had to take.
When it comes to the twist lock can caps they don't have a cap crimped onto the top, the bottom is crimped on. Bob Andersen's method certainly works but it involves uncrimping and recrimping the bottom of the can to get at the insulating disk. The only problem I see is that electrolytics have a life span, good quality ones can last for decades but even that isn't guaranteed, and you can only fold aluminum over so many times until it snaps off, should you have to open it up again.
However there is a similar method that someone else used on the other forum that is very similar, they filed off the crimped section altogether and glued the lip of the can that the bottom disk fits into onto the can. The one change that I would make is to use hot glue to cement the disk in place rather then epoxy, contact cement, etc, then all you need to do is heat up the can to get open again.
Regards
Arran
I had to do this with a pair of filter cans in my Rogers Ten-60, it had a pair of dry electrolytics where someone crudely cut each can in half with a hacksaw and then attempted to glue them back together with contact cement. I took them apart, cleaned off the goo, and then wrapped each section with a band of masking tape, then filed down almost to the tape line, then honed each edge perfectly flat on a piece of 600 grit sandpaper on a chunk of granite. I got lucky with the first can, the outside diameter of a 3/4 inch PVC pipe coupling almost fit perfectly, a little bit of hot glue and it was back together, the second can is larger so I will likely need to make a coupling by turning down something slightly larger.
I think the method Sylvian used would be the best, cut or pop the cap off the top and use something like that orange juice cap to couple it back together. I only did it this way because I had no choice if I wanted to salvage the old cans, some prior repairman made the decision which method I had to take.
When it comes to the twist lock can caps they don't have a cap crimped onto the top, the bottom is crimped on. Bob Andersen's method certainly works but it involves uncrimping and recrimping the bottom of the can to get at the insulating disk. The only problem I see is that electrolytics have a life span, good quality ones can last for decades but even that isn't guaranteed, and you can only fold aluminum over so many times until it snaps off, should you have to open it up again.
However there is a similar method that someone else used on the other forum that is very similar, they filed off the crimped section altogether and glued the lip of the can that the bottom disk fits into onto the can. The one change that I would make is to use hot glue to cement the disk in place rather then epoxy, contact cement, etc, then all you need to do is heat up the can to get open again.
Regards
Arran
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