short circuit at drive wheel tire

You do that, and it’ll more than likely vaporize something you don’t want to,…..

unfortunately, the proper fix is to pull the offending axle set  and re-insulate it,…..not a fun job, …..I’ve tried every trick in the book to get an arc out, gotten lucky with a band aid or two, but always wound up redoing the insulator,…..

I’ve seen some guys carefully pull a tire on engine, and work the I.D. till there’s a snug slip fit with fish paper soaked in 640 loctite, and some swear by this, …me personally, I like that press fit ….

Pat

I'd listen to Pat, you're right in his wheelhouse with this issue.

@gunrunnerjohn posted:

I'd listen to Pat, you're right in his wheelhouse with this issue.

Ha ha ha, “right in his wheelhouse.”

@harmonyards posted:

You do that, and it’ll more than likely vaporize something you don’t want to,…..

unfortunately, the proper fix is to pull the offending axle set  and re-insulate it,…..not a fun job, …..I’ve tried every trick in the book to get an arc out, gotten lucky with a band aid or two, but always wound up redoing the insulator,…..

I’ve seen some guys carefully pull a tire on engine, and work the I.D. till there’s a snug slip fit with fish paper soaked in 640 loctite, and some swear by this, …me personally, I like that press fit ….

Pat

Pat would injectable electrical insulation work. Just a question?.

@ThatGuy posted:

Pat would injectable electrical insulation work. Just a question?.

I doubt it, ….I’ve never gotten lucky with band aids, ….that’ll all depend on how much of a mess something like that might make especially on a high end  ( possibly painted ) model ….my theory has always been, if it’s arcing it’s touching, so until you physically remove the touch, it’s a crap shoot at best, ……I watched my pop for decades attempt to stop an arcing wheel with every trick in the book until he’d finally break bad, and drop the axle set out and knock the tire off…..

Pat

I've encountered this problem many times.  I've been successful often times in eliminating the short using my resistance solder machine.  It uses amps, not volts.  I place the grounding clamp on the axle or inside of the driver and the probe to the inside of the tire.  Turned all the way up I will often see a little puff of smoke where the offending particle was lodged.  Feel free to doubt it but I've done this numerous times and had very few failures.  A word of caution, a split second should be enough.  Don't do it longer.  Don't want to take a chance ruining the tire just in case doesn't work.

Jay

@harmonyards posted:

I doubt it, ….I’ve never gotten lucky with band aids, ….that’ll all depend on how much of a mess something like that might make especially on a high end  ( possibly painted ) model ….my theory has always been, if it’s arcing it’s touching, so until you physically remove the touch, it’s a crap shoot at best, ……I watched my pop for decades attempt to stop an arcing wheel with every trick in the book until he’d finally break bad, and drop the axle set out and knock the tire off…..

Pat

Yes I agree, I was just kicking it around but I agree if it’s touching it needs to be pulled

@Yellowstone Special posted:

Ha ha ha, “right in his wheelhouse.”

I wondered if anyone would catch that.

@Jay C posted:

I've encountered this problem many times.  I've been successful often times in eliminating the short using my resistance solder machine.  It uses amps, not volts.  I place the grounding clamp on the axle or inside of the driver and the probe to the inside of the tire.  Turned all the way up I will often see a little puff of smoke where the offending particle was lodged.  Feel free to doubt it but I've done this numerous times and had very few failures.  A word of caution, a split second should be enough.  Don't do it longer.  Don't want to take a chance ruining the tire just in case doesn't work.

Jay

And that’s where these types of remedies have their consequences, …..wreck a tire, and that can be an expensive proposition having to get one machined, ……good trick if you’re handy with a lathe, and have the raw materials, ….not so good if you don’t have that kind of skillset……not knocking your approach, but it’s got its drawbacks…

Pat

Model Railroader had a tip years ago about fixing a shorted driver if you know about where the problem is.

They suggested drilling a small hole at one end of the problem area. Then use a small jeweler's file to file out the insulation (plus probably a little bit of the driver casting) toward the problem until the short disappears. Don't file into the rim. Then fill the open arc with epoxy or some other non-conductive material.

The problem might be finding a file small enough, but they are available from watchmaking suppliers. I inherited some decades ago from my father who worked for Bulova.

Jim

thanks everyone for the suggestions. I have a heavy duty American beauty resistance soldering unit so I may try Jays suggestion. starting at a low setting and gradually increasing it giving it short zaps with the foot pedal. because I can see the arc which tells me were the short is I wonder if I could just drill a small hole thru it right at the insulation. then if it test negative for a short using a multimeter fill the hole with epoxy? if all this fails then I will be forced to remove the tire and reinsulate.  the late Joe Foehrkolb only lived about 30 minutes from me and has insulated hundreds of drive wheels doing his conversions. his services are surely missed.

Let us know the outcome! ….share your “ how to” so others can learn,….

Pat

I have never ruined a tire using this technique.

Just because someone's never used this technique doesn't mean it won't work.

If push comes to shove, send me the driver and I'll do it.

Jay

@Jay C posted:

I have never ruined a tire using this technique.

Just because someone's never used this technique doesn't mean it won't work.

If push comes to shove, send me the driver and I'll do it.

Jay

Ok, ….and what will you do IF you do ruin it? ….do you have a clear path out if it did happen?

Pat

I have hundreds of tires and the ability to make them.  Contrary to what some will tell us, it's not rocket science.

Jay

Might be a few examples in these albums.  I hope this is allowed.  https://photobucket.com/u/jayc...f1-9edb-c132302de2c4

Jay

@Jay C posted:

I have hundreds of tires and the ability to make them.  Contrary to what some will tell us, it's not rocket science.

It does require the proper tools and expertise however.  I do electrical design, and it's not rocket science, but a lot of people certainly don't have the ability or tools to do what I do.  I suspect it's exactly the same situation making these 2-rail tires properly.

Making the tires is only part of it,

Jay

@Jay C posted:

I have never ruined a tire using this technique.

Just because someone's never used this technique doesn't mean it won't work.

If push comes to shove, send me the driver and I'll do it.

Jay

Thanks Jay. let me try my resistance soldering unit first and see if that removes the short. if not a may contact you regarding a repair. The engine is an Overland models Western Maryland H9 built by Ajin.

@Jay C posted:

I have never ruined a tire using this technique.

Just because someone's never used this technique doesn't mean it won't work.

If push comes to shove, send me the driver and I'll do it.

Jay

No, that ain’t got nothing to do with it, ….it’s called do the job right, …..if you’re happy with band aids, have it your way,….I prefer not to half *** my work,….

Pat

But I will add Jay, …very nice work on those drivers!

Pat

"No, that ain’t got nothing to do with it, ….it’s called do the job right, …..if you’re happy with band aids, have it your way,….I prefer not to half *** my work", per you?  Means nothing.  I realize you hold yourself in high regard.  I don't.

Jay

@Jay C posted:

"No, that ain’t got nothing to do with it, ….it’s called do the job right, …..if you’re happy with band aids, have it your way,….I prefer not to half *** my work", per you?  Means nothing.  I realize you hold yourself in high regard.  I don't.

Jay

I’m so sorry, I didn’t realize I was in the presence of the almighty,…..🙄

Pat

I used to own a Sunset 2-8-0. Supposedly it was used but it had a dead short so I knew it was never run. It took me a while to find it but it was a tiny tiny piece of metal lodged in the insulation of one of the drivers. I carefully worked that piece of metal out of there and it ran until the day I sold it. My repair did seem to remove a very small amount of the insulation but it never shorted again.

@David Eisinger Good luck with your locomotive.

@Jay C Boy those are really some nice drivers!

following this thread, my question for JAY is exactly what does applying  the resistance iron to the driver do? is it a matter of burning off a 'particle' as you described? that is like Phil mentioned, a piece is shorting the driver by bridging the insulation between tire and center?

Thanks for the reply.

Chris,

It's probably a question of semantics.  Backing up slightly, before I attempt using the resistance soldering tool/machine, I will use the most powerful magnifying visor I have and look for anything obvious.  If I find nothing I will use an ohm meter to get some sort of resistance measurement.  From there I will crank up the resistance machine as far as it will go.  I then carefully clamp one lead to the axle or backside of the driver and hold the probe against the inside of the offending tire.  This is done just in case there is a disaster and this technique doesn't clear the problem.  Any mark, or scar, will be on the inside where we can't see it.  This did happen one time but it wasn't bad and after a little cleanup it was gone.  A plated tire, like what's on the Overland model in question is, in fact, more susceptible to damage so you have to be extra careful.   I usually only tap the foot switch once to see if I can clear (vaporize) the offending material.  Sometimes I have to do it more than once.  Often times you'll see a little puff of smoke or hear a popping sound.  After using the resistance solder machine for a while you can tell if there is continuity.  I always go back to the ohm meter and verify the short is gone.  If I get lucky and see the area where the miniature puff of smoke and/or popping sound came from I will try to clean out any debris.  I suppose I've done this procedure a couple of dozen times and have never had another issue with the same driver.  This tells me it was ether fixed or the client just didn't want me to work on the model anymore.  Probably could go either way.

I just realized, I didn't really answer your question.  Yes, we're trying to burn/vaporize/eliminate a small metal particle lodged between the driver's center and tire.

I hope at least a bit of my rambling made sense.

Jay

Interesting thread but please guys, be nice.

I have to agree 110% with Jay…

I have successfully used that technique myself, many times.

I spent 11+ years as a custom builder (2009-2020), as my sole source of income. I worked primarily in O, and some S. The vast majority of my projects involved the conversion of brass steam (and occasionally diesels) to P48. I was also redetailing locomotive superstructures, upgrading drives, doing extensive bashing, custom painting, weathering, installing DCC, and lighting. In that timeframe I converted over 300 pieces of equipment.

Forsyth Rail Services

www.mattforsyth.com

To date, I’ve disassembled, machined, insulated, and quartered many hundred steam axle sets, with 99.8% success, but on rare occasion, there will be a cantankerous tire that develops a short between itself and its driver center. The offending item is almost universally a tiny metallic shard that “bridges the gap”.

I have a 16-40x binocular dissecting scope, that lets me get a highly magnified view of the layer of insulation between tire and center. Using a new X-acto #11 tip, I’ve sometimes been able to reach in and remedy the situation by dislodging the offending shard.

When that doesn’t do the trick, and the short persists, I’ve found that vaporizing the offender with a stiff shot of amperage from a resistance unit or even a powerpack takes care of the problem. I’ve done this many times with great success, and have never damaged any of the components.

I hook one lead to the back of the driver center, and the other to the flat rear of the tire and HIT IT! There’s usually a mousetrap-like “snap” sound that instantly occurs upon throwing the switch. A quick continuity check with a meter shows the problem has been resolved…

Matt Forsyth

PS, the attached image is an old US Hobbies UP 2-8-0 that has been converted to P48, and has also received a prototypically accurate, detailed tailbeam. Anybody that knows US Hobbies locos, knows that the tailbeams were just a simple block of brass…

Matt,

Absoultely beautiful tail beam on the USH UP 2-8-0!!!

Lee Gustafson

Just another one of those niggling problems we've encountered in the hobby that needs no resolution...

...in the world of Dead Rail...a.k.a., battery-powered.

Gorgeous workmanship, Matt!

Jay and Matt, thanks very much for your thoughtful replies. I now get the concept.

@PRR Man posted:

Jay and Matt, thanks very much for your thoughtful replies. I now get the concept.

Welcome, C.C.

Hope all is well with you…

@Lee G. posted:

Matt,

Absoultely beautiful tail beam on the USH UP 2-8-0!!!

Lee Gustafson

Lee,

Appreciate the accolade; most kind…

MF

@dkdkrd posted:

Just another one of those niggling problems we've encountered in the hobby that needs no resolution...

...in the world of Dead Rail...a.k.a., battery-powered.

Gorgeous workmanship, Matt!

Thanks so much!!

Jay is a very talented 2 rail modeler. He has helped me out in the past and I am glad to know him. I don't think he would ever put a zamic under frame on a brass engine. Just saying.

@Jay C posted:

Might be a few examples in these albums.  I hope this is allowed.  https://photobucket.com/u/jayc...f1-9edb-c132302de2c4

Jay

Jay,

finally was able to get into your photo bucket account..  Interesting stuff- I especially liked the quartering jig-very simple design,

Rob