An interesting foil prob

[Purple Fencer]

Here's one I ran into at the All-Cals a couple of weeks back.

I'm brought a foil that's grounding out...no reaction at all when the tip is deprssed.

As is my habit, I remove the tip (French) and prepare to sand the ends of the spring. The weapon's still plugged in my test box, and even with the tip, spring AND screws removed, the light's still on!

I took a Q-tip, wetted it in rybbing alcohol and cleaned out the inside of the barrel, which was quite dirty. A very slight sheen appeared on the Q-tip, mixed in with the dirt. It looked vaguely mettalic. The light went off on the box and the tip operated normally; the fencer used it for the remainder of the tournament.

Here's the question:

The only way I can figure what happened was that the french tip (which was somewhat old) had been worn down over time and miniscule metal flakes built up with the dirt & crud inside the barrel; creating a bridge for the electricity from the wire to the barrel, thus shorting out, much like the spring bending over.

Did I figure this out right? Seems strange.

[Zelda]

Remembering my senior physics which was nearly 10 years ago, that sounds feasible. However, it could also be some sort of problem with the spring, and once exposed to fresh air it started working again (dont laugh, it happens with my springs).

[Purple Fencer]

[quote]Originally posted by Zelda:
<strong>Remembering my senior physics which was nearly 10 years ago, that sounds feasible. However, it could also be some sort of problem with the spring, and once exposed to fresh air it started working again (dont laugh, it happens with my springs).</strong><hr></blockquote>

Zelda...there was NOTHING in the barrel...I'd removed the tip, screws AND spring...there was no way for the circuit to reach the barrel.

[sallearmourer]

What they did was used graphtic to try to get a the tip to slide better. graphtic contains lead which conducts. See it in epee all the time.

Tim

[Purple Fencer]

[quote]Originally posted by sallearmourer:
<strong>What they did was used graphtic to try to get a the tip to slide better. graphtic contains lead which conducts. See it in epee all the time.

Tim </strong><hr></blockquote>

Ahhhhh! I'll ask him about it, but it seems likely. Thanks, Tim!

[Mergs]

Sam,

Was the barrel chrome plated? That could have been the source of your metal that caused the short. Not sure how much stuff you pulled out, but it would have had to been quite a bit to bridge from the button to the barrel. Unless the cup was cracked.

[Purple Fencer]

[quote]Originally posted by Mergs:
<strong>Sam,

Was the barrel chrome plated? That could have been the source of your metal that caused the short. Not sure how much stuff you pulled out, but it would have had to been quite a bit to bridge from the button to the barrel. Unless the cup was cracked.</strong><hr></blockquote>

I don't remember, and didn't know to check. I could not see the cup.

Either way, simply cleaning out the barrel seemed to work.111111111111111ccccc,.kkkkk

Whoops! Sorry about that...kitten walking across the keyboard!

[MHS Fencer]

Just a little FYI, graphite is a crystal form of carbon with free electrons and it conducts on its own. There is no metallic element such as lead in it.

[neevel]

That's very likely what it was-- either graphite (naughty, naughty) or bits of metal flaked off from the point parts.

Another possibility: some damaged insulation (wire or cup) inside the point which had managed to come into contact with the side of the barrel or the blade. Jiggering it with the Q-tip caused it to shift just enough so it wasnt touching. A wire broken away from the contact, with the bare end still resting against the contact (and hence not producing a white light), but then getting jiggled into touching the barrel, would also cause this.

-Dave

[Purple Fencer]

[quote]Originally posted by neevel:
<strong>That's very likely what it was-- either graphite (naughty, naughty) or bits of metal flaked off from the point parts.

Another possibility: some damaged insulation (wire or cup) inside the point which had managed to come into contact with the side of the barrel or the blade. Jiggering it with the Q-tip caused it to shift just enough so it wasnt touching. A wire broken away from the contact, with the bare end still resting against the contact (and hence not producing a white light), but then getting jiggled into touching the barrel, would also cause this.

-Dave</strong><hr></blockquote>

Hmmm...a possibility I hadn't considered. But wouldn't normal usage of the weapon shift the wire back away from the contact? The weapon worked normally for the rest of the day.

Now I REALLY wish I was able to go to the armorer;s college. Maybe I'll ask Don Clinton's opinion when I see him tonight...he;s picking up some $$ from me for a blade I sold for him

[damianip]

[quote]Originally posted by MHS Fencer:
<strong>Just a little FYI, graphite is a crystal form of carbon with free electrons and it conducts on its own. There is no metallic element such as lead in it.</strong><hr></blockquote>

I think that Tim meant "lead" as the equivalent of pencil lead (grahite) not lead: Pb.

Paolo

[Purple Fencer]

Well...I saw Clinton and when I explained the prob, he immediately said it was most likely graphite lubricant causing the problem...the rest of th night I spenmt watching him repair a reel.

[DHCJr]

Both answers could be correct, but I would ask the question if it was Uhlmann or AllStar. Both had a problem with the chrome flaking and causing this problem. But you did the right thing.