Soldering capacitors flush?

Started by mc50, May 09, 2021, 02:14:18 AM

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mc50

Hello,

For years I've been soldering capacitors (including box capacitors) leaving at least 1mm between the bottom of the cap and the board, out of concern that soldering too close to the capacitor body might damage the part. Even while my soldering technique has improved to the point where 2 seconds is the most I usually need to take for a joint (and most times I do it in 1s), I've kept this habit.

Clearly functionally it shouldn't matter. But I've recently paid more attention to commercial products and most of them solder the box capacitors at least (but many also the electrolytics) pretty much flush to the board. That makes sense, it'd definitely be easier to place them on the board prior to soldering and they'd tend to move less while soldering, not to mention that the board looks better in the end (mine will be slightly slanted, can't be completely precise).

Are caps (especially box film caps, but all of them) meant to be soldered flush to the board when space allows, and am I being unnecessarily careful?

I know, not a prize question...  :)

FiveseveN

Yes.
Heat is going to get into your caps a lot faster through the leads than through the board and body anyway.
Quote from: R.G. on July 31, 2018, 10:34:30 PMDoes the circuit sound better when oriented to magnetic north under a pyramid?

mc50

Alright, good to know, will make my job easier in the future. At least I'm not in bad company, some of Analogman's caps are pretty high as well:


duck_arse

yes, flush to board. the case then provides mechanical support for the leads, prevent the mass of the body moving about - the leads are then not strained, your joints then don't go dry via vibration effects.
You hold the small basket while I strain the gnat.

mc50

Fair enough, makes sense and point taken: that'll be my strategy going forward.

Just for the sake of argument though, pedal caps tend to be tiny things weighing almost nothing, I'm not sure I see how they're going to be subject to much vibration strain. There are tube amps from the 60s still working with point-to-point wired big caps hanging on for dear life by their (long) leads, and certainly an amp is likely to be much more vibration prone (and more severely, at that) than a pedal.

But again, of course, it makes sense to always be prudent if it doesn't cost anything, and so I shall proceed. Thanks!

PRR

A major, tho now historical, exception is Polystyrene caps. They melt easy. They are good, but expensive, and unsuited to factory soldering, so are now mostly faded. Unless you shop for "exotic" caps.
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vigilante397

Quote from: mc50 on May 09, 2021, 01:18:08 PM
There are tube amps from the 60s still working with point-to-point wired big caps hanging on for dear life by their (long) leads, and certainly an amp is likely to be much more vibration prone (and more severely, at that) than a pedal.

The difference there is that in point-to-point amps the leads are typically looped at least once around the terminal before soldering, giving a solid mechanical connection outside of the electrical connection.
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iainpunk

Quote from: PRR on May 09, 2021, 02:28:20 PM
A major, tho now historical, exception is Polystyrene caps. They melt easy. They are good, but expensive, and unsuited to factory soldering, so are now mostly faded. Unless you shop for "exotic" caps.
thanks for the warning, i haven't used my stash yet, but ill keep that in mind while working with them.

cheers
friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers