Subject: RE: fuses, was new wiring diagram (long)
Author: Tom Bowes
Date: Feb 11, 2001, 6:33 AM
Post ID: 1705380048
Jay Williams wrote:
While we're on the subject of electrical systems, does anybody but me have a problem with the fuse holders becoming periodically non-conductive? |
Jay,
I used to have this problem with my 1960 VW, which used the same type of
fuses. You are up against two major obstacles with the old-fashioned
"bullet" type fuses; disimilar (and unplated) metals, and limited
contact area. Looking at my Ambo fuse block I can see that the fuse
holders are either copper or brass, both of which do tarnish, forming a
non-conductive layer on their surface over time. Some of my fuses have
unplated copper ends and others look to be tin plated. Given time and
some moisture, galvanic action will cause the metals to interact and
corrode. Unfortunately, the limited amount of contact area on these
fuses doesn't give you much leeway as far as having a choice of whether
to maintain a good connection surface or not. Scraping doesn't help for
long because the roughness left by the scraping only serves to further
reduce the contact area.
Here are some things you might try in order to fix the problem more or
less permanenetly:
1) For about $40 you can get a 24K gold plating wand kit from Caswell
plating "www.caswellplating.com" and gold plate the ends of the fuses
and holders. This is the same approach used by electronics manufacturers
who regularly gold plate pin and socket connectors to ensure
reliability. This is because, unlike copper, gold does not tarnish. Of
course, you would want to repair the previous damage to the fuse
holder's suface prior to plating.
2) In the electrical world we sometimes use a product called
"KOPR-SHIELD". It is basically colloidal copper powder mixed with
petroleum grease. It would be somewhat more effective as it would keep
the air away from a freshly cleaned connection, and theoretically the
copper powder would help to maintain the connection. The stuff used to
be available at electrical supply houses that stock T&B products, but I
can't even find it listed on the T&B web site these days. It is very
messy and somewhat expensive, but works great on battery and sundry
electrical connections on cars and bikes. It also works as a great
practical joke when smeared on the back of a padlock! You might also try
Anti Seize, which has nickel as well as copper in its mixture, and is
more widely available. Again, smoothing the contact surfaces would be a
wise move in order to maximize current carrying capacity.
Tom
'70 Ambassador
'82 V50-III
Shelby Township, Michigan