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Michael, what is the "goop" you use to adhere the film caps down with? I have tried hot glue but that won't hold the big PS film caps in place in the underside of the chassis. I am guessing that the goop you use does hold these large caps under the chassis with no problems, thanks!
Follow Ups:
about the use of caps in a voltage doubler. I am restoring a Lafayette 250A that uses a voltage doubler. I noted in your article that you 3x the power supply caps off the diode, the ones in the Lafayette is 250 ufd, so would you recommend a higher value? thanks!
Not Mike, but the answer is yes. If you have the room, install the 820 μF. parts Jim McShane sells. You also need inrush current limiting thermistor(s). Clanging power trafos are to be avoided and "popping" fuses are no fun.
BTW, while the "beast" is on the bench, upgrade the SS diodes too.
Eli D.
Ditto!
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Standard silicone is corrosive. Make sure to use an electronics grade like Wheezer posted. The smell with associate with silicone is acetic acid.
Russ
The household and plumbers goop doesn't have corrosive properties because I have used it for seven years now and I just puled some chassis mounted caps out of the mc240 I did six years ago and the stuff peels right off and shows no signs corrosion.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
standard silicone caulk is corrosive. No need to take my word for it. A simple web search will provide all the answers needed. They do make acetic free silicone and that is fine.
Did find this in a MSDS sheet for plumbers goob. It would make me think twice for film caps. Maybe you didn't read it?
Not recommended for use on polystyrene, polyethylene, polypropylene, Styrofoam™ or paper products, and any items that come into contact with food, drinking water or animals.
There is a reason why they make an electronics grade silcone adhesive. Why not us the correct product for its intended useage? Penny wise and pound foolish?
...the incompatibility with plastics takes two forms. In one form, the solvents in it attack polystyrene and similar materials like styrofoam by softening and dissolving them. The other form of incompatibility is that the stuff simply doesn't stick to some plastics like polyethylene and polypropylene because these materials are fairly inert and quite resistant to the solvents.
Personally, I don't use the stuff because I find the smell nauseating. Also, if I can't devise a mechanical of means of attaching a new part, I don't use it.
Steve
Thanks for the info.I only use it because I rebuild a lot of vintage gear with exotic modern caps and I don't want to drill and cut the units up because they will kill the vintage value..This stuffs holds really well but with a quick twist you can also remove it with no traces whatsoever..On kit amps where they have preexisting holes such as in the citations or Eicos or Heathkits,I use the clamps in that situation.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Edits: 01/21/15
Thats possible..Its a form of silicon but its safe and thats why a little tube is five bucks.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Based on recommendations here on the Asylum. But after I got it home, my concern is the caution on the package: "Not recommended for use on polystyrene, polyethylene, polypropylene, Styrofoam™, or paper products."
I often use polystyrene and polypropylene caps, and I'm not willing to risk a bad reaction between Goop and expensive caps.
Just an F.Y.I.
I can assure from the years of using goop more than probably most anyone I have never had any issues with it and neither did Terry Dewick who does many, many ,many,amps and preamps.
I did these five years ago and there are some very some expensive analytic polys and there is no sign is any corrosion whatsoever. The soft body poly couplers I have used it on as well and I haven't had any issues yet.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Edits: 01/21/15
I have no doubts that you haven't, Mike. But it's the "yet" which concerns me. The Amazing Goop people put that warning on the package for a reason. I wouldn't want to find out what that reason was on a $250 V-Cap which turned to goo because of a chemical reaction.
I'll use Goop for electrolytics, the metal bodied Russian mica, oil, and Teflons, etc. and stick to electronics grade silicone adhesive for the plastic caps.
No matter what you buy from aspirin to a bottle of pop to a tube of toothpaste,there are always warnings of some kind.The companies do this to cover all angles but I assure you that with all the expensive vintage gear I have,something would have shown up in seven years time..It peels off like a piece of rubber and it leaves absolutely no trace of anything.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Drink the Kool-Aid!
Dave
his events, culture changing to say the least!
After trying too many to count, my staple electronics adhesives are:
Permatex Sensor Safe Blue if you never want to remove the component once cured.
Next is GC Electronics grade sealant adhesive # 19-155
http://www.amazon.com/GC-Electronic-Silicone-Sealant-Adhesive/dp/B004SPJN6K
This takes some work but the part can be removed.
...Both have zero odor.
Cheers,
W
because you may want to put it back to original and thats why goop is the safest solution.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
or mount a rubber grommet(from McMaster Carr)in-between the part and the chassis with either of my recommended adhesives.
Or whatever size rubber grommet is needed. Local store bought grommets are of a plastic composite and adhere poorly.
Randy
Any of them are fine..I use the household or the plumbing one or even the automotive but they are all the same for that job of mounting caps.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
That'll do fine.
However, because I have access to it, I use Corning 732 Multi-Purpose Sealant.
In my case, I gotta either wear gloves when working with the stuff or take some serious anti-histamine, as I'm actually allergic to silicone (and latex- found out the "hard way"; turned out to be a bummer for me and the ladies back in my nefarious "glory days"! LOL).
Dman
Analog Junkie
also, Michael, these Vishay MKP film caps are fine for using in power supplies to replace 'lytics, correct? I ask because they are so small!
I use the Panasonics and the Wimas and the CDEs and Unlytics..
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
DC link MKPs, not sure if they are suitable for power supplies, but I thought I had read that somewhere...
Yes
They are excellent in power supplies.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
What do you think of Wima capacitors a coupling capacitors. I know they were very popular in that role for a while, but they seem to have gone out of favor.
Dave
thanks, Michael, so they will hold my outboard film caps in place on the metal chassis underneath? BTW, I never received the Sherwood knob, hope you didn't send it and it got lost. thanks, Randy
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