Heat Sensitivity While Soldering Capacitors

[jf4828]

For the first time in my life I’m building a crossover with pretty expensive capacitors. To keep them close, I plan to solder 1 leg close to where the axial lead comes out of the next. Is there any danger in getting it too hot? This is poly film cap. Just for knowledge, how do other types of caps handle heat from soldering as well?

Normally I don’t worry about it and everything is fine but just want to take extra care here....

 

[rayma]

Not a good idea to solder close to the body of a film capacitor, that will likely do internal damage.
There's no point to minimize lead length in a crossover. The lead parasitics are truly negligible (<10nH/cm),
and strain relief is also important. In any event, with expensive, sensitive parts use a heat sink clamp
on the leads during soldering.
Clip On Heat Sink | HT-156

 

[AllenB]

Make sure your leads are clean and your iron is clean and hot, then you can solder taking a short time. This quick process ensures heat doesn't get a chance to travel up into the capacitor.

 

[olsond3]

I would clamp a hemostat style locking plier on the wire next to the cap body to keep the heat from going into the cap. 5-1/2 in. Locking Clamp Pliers

 

[jf4828]

Thanks all! I usually do what Allen B. suggests but will add a sink I have. I’ve also ordered the clamping pliers to have on hand because these seem handy for all sorts of soldering tasks

 

[xrk971]

Also be very careful with not accidentally touching the outside of a film cap body with the hot iron. I was clumsy and tried to solder another part too close to the body of a 36uF 250v MKP. The iron touched the outside and melted maybe 1/4in deep gash into the 50 or so film layers. Shorted the cap out and I learned an expensive lesson. At least it was not a boutique cap.

My expensive boutique film caps come in a thick paper cardboard (Miflex)shell or PVC tube (Clarity) which gives them some more protection.