From MLJS45–(at)–rodigy.com Sun Oct 8 11:15:45 CDT 1995
From: MLJS45–(at)–rodigy.com (James Mcshane)
Subject: Forming Surplus Photoflash Caps
Date: 8 Oct 1995 15:17:36 GMT
I’ve been watching the posts on using photoflash caps, and wanted to
offer a safety and performance tip that has worked well for me. When
working with surplus photoflash caps, it is very important to SLOWLY re-
form them before even considering using them in regular service. I try to
keep current flow through the cap to <1ma. as I bring the applied voltage
up. I form them to rated voltage +5% as a safety factor.
Be advised I have had about 10% literally explode during forming! That’s
why I use a small wooden box to contain the cap during forming. And I
always form the one at a time, not as a “bank”. Caution is very important
One last tip- if you happen to get hold of Rubycon branded caps the key
that you have a bomb, not a cap, is that the bottom of the cap begins to
expand out, sort of dome-like, before you get to rated voltage. Discard
these units. They will fail.
I too have used these caps in a variety of units for years with zero
failures- after proper re-form. I like ’em a lot. Poor man’s Black Gates?
JAMES MCSHANE MLJS45–(at)–rodigy.com