On Mon, 14 Nov 2016 17:45:28 -0800 (PST), whit3rd
wrote:

On Monday, November 14, 2016 at 2:44:55 PM UTC-8, wrote:

I found 220 mfd 450 caps at JustRadio.com. I'm not sure if these will
discharge fast enough.

For a welding purpose, 100l milliseconds is very fast (no functioning
capacitor you are likely to find would have too high ESR for this job).

ESR gets to be important with low voltage high current, where a fraction of
a volt of ripple is a malfunction. Fraction of a volt difference on a 450V capacitor
charge is negligible.
So photoflash rating is probably not necessary?
Thanks,
Eric