Yeah, it’s just gone nuts. 5000 of them - that’s 2500 cars! I don’t think my layout will hold nearly that number, and still have room to move trains. Maybe you’d get 2400 working cars once you account for a few that don’t work, and then inevitable dropped few (good luck finding that!). Still… I actually just sked my friend who’s still in the industry to comment, since this sort of thing just discourages small DIY projects - either pay through the nose, or have so many leftover parts you’d never use them all in several lifetimes. It’s good to have a small inventory of common parts to build things, but 5K is not a small inventory. Digi-Key drove out the small buyers a long time ago, with their order surcharge - I think it was $25 if your order was under $100 or something, so you need $20 worth of parts for your project and then pay an additional $25 plus shipping - even with Radio Shack’s inflated prices it was sometimes the cheaper option to pay the sales tax but no shipping or surcharge. Now we don’t even have that option. Not too worried about pasives on eBay (except electrolytic capacitors), but things like microcontrollers - I’d be willing to bet most of the ATMega328P/PU chips on ebay are really remarked ATMega328P - there ARE differences besides the ‘pico power’ mode and you need different fuse settings when programming them. They might even be ATMega168’s - same pinout, less RAM and Flash. Common trick with the Chinese selelrs - remark a cheaper chip as the more expensive one. Downright dangerous when working with things like TRIACS for AC line voltage control. Not all are like this, but when even the known good suppliers ended up sourcing fake FTDI USB chips a couple of years ago, wh can you even trust?
Well, the right resistors (on my 3rd try) finally came and I started trying to install them. I followed the exact same procedure that I saw on You Tube, and it was driving me nuts. The resistors wanted to stick to everything except the darn axles. Stuck to the tooth pick, stuck to my fingers, stuck to the tweezers, but could I put the resistor in the right location on the wheel and axle and have it stay there, noooooo. Every time I tried to position it, the resistor stuck to the tweezers or my finger, not to the wheel or axle. GRRRRRRRRRRRRRRRR.
If you get any glue on the ends of the resistor, you cannot make electrical contact with the conductive paint.
Finally I found the way to do it with continued success. The glue is strong enought compared to the actual strength required to hold the resistor in position, that you only need to apply the glue to one end of the resistor. I started putting a small drop of glue on the axle, not putting any glue on the wheel, picking the resistor up by only the top end and placing the resistor in the glue on the bottom end by sliding the resistor along the axle towards the wheel, holding the resistor at about a 45 degree angle, and positioned it with the top end just leaning on the wheel. The tweezers never come near the glue and the glue always stayed behind the resistor.
After the glue dried, the conductive paint did the rest. Worked with 100% success, all had 9.5k - 10k resistance between the wheels and I could not move the resistor, even though it was only glued at one end. I have now done 80 wheel sets and will do many more this evening. Finally making progress. Happy Camper!
I used a thicker type of CA, and put one tiny drop on the axle, then picked up a resistor with my tweezers and set it in place. That kept the glue off the tweezers and, unless I put too big a blob of glue on the axle, there was no change of covering up the conductive ends of the resistor. Seemed a lot easier than trying to hold the resistor in the tweezers and apply glue to it. Being the thicker type, it takes a little while to set, which means you have plenty of time to pick up and palce the resistor, no rushing. And it doesn;t run down and dribble where you don’t want it.
The stuff I used was a Locktite branded stuff, in a fancy boddle with two arms to squeeze on the sides (inside is a small tube of glue - the container looks big, but it’s a small amount of glue - which is not a bad thing) and it had a long pointy tip that dispensed a nice small drop, no fiddling with special applicators or layoing out a puddle of glue and using a toothpick or something. Compared to buying a larger size bottle of CA< it was expensive, but I also found regular viscosity CA by Locktite that, instead of one large bottle, is a pack of 10 small tubes - that way if a tube dries up or the nozzle clogs, you aren’t throwing away a large quantit, and the rest all stays frech because the tubes are sealed. I still have some unopened tubes I haven’t touched in 5 years and they are still usable. For the occasional small use of CA, this is actuallymuch more economical than a large bottle that often ends up going to waste despite best efforts to keep it sealed. If you are going to use a lot of CA in one go on a large project, obviously the larger bottles are the way to go.
Edit: if this link works, pretty sure this is the one I used for my resistor wheels:
I used the Gorilla Super Glue Gel. Also gives enough time to position, dries in about a minute and does not run as it is a thick gel. One $4 bottle can do about 5,000 wheels!
I am quite convinced that 5-minute epoxy would be a seriously bad choice, even though you have 5 whole minutes before it starts to set AND it’s very thick and not runny.
So don’t even think of trying it. I know I won’t. It will never work.
After getting home from work this evening, I put a movie in the computer and started putting resistors on a box of axles. First I glued all the resistors to the axles, let them sit for about 20 minutes while I ate 6 Chick-Fil-A chicken tenders then followed that up with the nickel conductive paint. Took about 2 & a half hours to resistorize all 100 axles. After testing all of them with my Fluke, all but 3 tested sat, and after removing the nickel paint and re-applying new nickel paint from those 3, even those worked.
Ready to start installing them on my rolling stock, 1 axle per truck. When I’m done with that, I have another box of 100 axles to start on.
Once they are on my rolling stock, I will have the 200 metal wheels that I removed from my rolling stock to again, install resistors on.
I wonder how much resistance that stuff adds. I’d suspect I would need less than a 10K resistor, most of those “conductive glue” type things are carbon suspendsed in a glue, which is why it is super cheap. Since strict accuracy is not a requirement for detection wheelsets, it’s probbaly a reasonable alternative. Don;t trust the label when it says you can use it on electronic repaisr and stuff though. I wouldn;t for a minute try to fix something like a broken trace on a tv set PCB with that stuff.
I do know that with the expensive silver stuff I used, the resistors all measured within their expected tolerance - so the silver conductive paint over the width of an HO axle added negligible resistance to the circuit. I’ve seen that stuff all over the place, next time I see it I’ll grab a jar and try it.