Rebuilding Sprague Electrolytics - HELP - Printable Version
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RE: Rebuilding Sprague Electrolytics - HELP - Ron Ramirez - 05-16-2019
So I tried again just a few minutes ago.
I could not get the bakelite piece out of the first can without breaking it.
Then I ground the lip from the end of a second Sprague cap.
After doing so, I made a discovery that you guys who have done this before had not mentioned.
There is a rubber ring at the bottom of the bakelite piece. This is what keeps the bakelite in and may prevent its removal.
I found that if I carefully went around the bottom with a knife, cutting away the rubber ring between bakelite and metal, that the bakelite piece could then be removed fairly easily.
I had ground enough material away from the first can. It was the old, hardened rubber holding the bakelite in place.
Results of the first (left) and second (right) cans, below:
Now, if I could only get good enough with my Ryobi "Dremel" tool that I don't let it slip and mar the outer edge of the bottom of the cans...
RE: Rebuilding Sprague Electrolytics - HELP - rfeenstra - 05-16-2019
I suspect that when I use a belt sander to remove the lip, I am sanding a little of the rubber ring away making it easier to remove the Bakelite assembly. I did remove the rubber ring, at least on the Mershon's which gave me the room necessary to roll the edge of the can over again on reassembly. It looks like, though, that I did not remove the rubber ring when I did the Sprague's.
RE: Rebuilding Sprague Electrolytics - HELP - Ed Locker - 05-16-2019
That looks like quite a puzzle, but I'm sure you can glue all those pieces back together!
Ed
RE: Rebuilding Sprague Electrolytics - HELP - Ron Ramirez - 05-16-2019
I will try, Ed...
RE: Rebuilding Sprague Electrolytics - HELP - jake wells - 05-16-2019
Ron wear a mask and gloves after removing the bakelite plug the guts are covered in very toxic chemicals ( PCB ) you don't want that stuff on your hands. The wet type is not as bad since they contain a mild solution of boric acid.
RE: Rebuilding Sprague Electrolytics - HELP - Ron Ramirez - 05-17-2019
The Sprague and Mershon capacitors are the wet type, originally using boric acid.
RE: Rebuilding Sprague Electrolytics - HELP - morzh - 05-17-2019
I can still hear the liquid splashing inside mine.
RE: Rebuilding Sprague Electrolytics - HELP - Ron Ramirez - 05-17-2019
That's unusual. I don't think I've ever come across one which still had liquid inside. Every one I have ever encountered was dried out.
RE: Rebuilding Sprague Electrolytics - HELP - Phlogiston - 05-17-2019
I would say that about 1 out of 10 of those that I cut open are still wet.
RE: Rebuilding Sprague Electrolytics - HELP - Ron Ramirez - 05-25-2019
Hey Ed
I did manage to get most of the pieces of the Sprague bakelite base glued back together today. Photos later. Now we'll see how it holds up...
I restuffed a second Sprague can today. Unfortunately, trying to roll the cut edge back over did not go well and left a gap between the bottom of the can and the round, flat connection on the 70 chassis. So I ended up soldering not one, but two pieces of 14 gauge wire to the bottom of the can where it was (poorly) rolled back over, in order to establish contact between the bottom of the can and the negative terminal on the 70 chassis.
Tomorrow, after thinking this over some more, I may try restuffing the first can I opened up. I may try Bob's (klondike98) method of adding a wire for a negative terminal to the bottom of the can this time as shown here: https://philcoradio.com/phorum/showthread.php?tid=15041&pid=111864#pid111864
RE: Rebuilding Sprague Electrolytics - HELP - Ron Ramirez - 05-26-2019
This discussion is continued here:
https://philcoradio.com/phorum/showthread.php?tid=20031
along with the discussion about rebuilding my own Model 70 to use Ed Locker's AVC mod.
RE: Rebuilding Sprague Electrolytics - HELP - vintageradiojohn - 12-25-2019
You guys are all starting from the wrong end. Open the top by removing the vent plug, & remove the old guts from the top.
A new stud & cap can be inserted from the top, & the cap re-installed.
I've done many of these this way over the years, & they look untouched.
John
RE: Rebuilding Sprague Electrolytics - HELP - Ron Ramirez - 12-25-2019
Details. How do you remove the vent plug/cap?
RE: Rebuilding Sprague Electrolytics - HELP - vintageradiojohn - 12-25-2019
I use a dental pick to pry the vent cap off. Then use a dremmel burr to enlarge the hole. Needle-nose pliers used to twist & remove the guts in pieces. I solder a new electrolyic to a brass bolt, & drill a small hole in the side of the can near the bottom for the neg. lead.
The whole works fits into the hole in the top, & then put the vent cap back on.
It takes a bit of time, but the results are worth it.
RE: Rebuilding Sprague Electrolytics - HELP - Phlogiston - 12-25-2019
This can be difficult.
You have to use a hole saw to remove the bottom of the vent. Then pull the 10lbs of goo through the 2lb hole.
I don't do this anymore - -