peter220950 Posted July 31, 2014 Share Posted July 31, 2014 Bit of a strange question, but does anyone know of a conductive grease (preferably) or oil, other than Electrolube, (that I do know about)? I have built a turntable for a DCC layout (I know this is non-DCC but the principle is the same it's continuity I'm after) - one track terminal is a ball bearing running on copperclad, which seems to be working fine, the other is via the turntable pivot, which was fabricated from a brass board dowel joint, in practice it's giving the odd stutter which is a complete pain with a sound loco, which then needs to go through a start up sequence again. I thought that a drop of grease in the bearing cup might do the trick, not sure if copper grease is conductive, logic says it should be. Electrolube might do the trick but could leak out if the board is rotated in transit, hence the preference for a grease. Failing that I shall have to either put a small ball bearing into the bottom, or mill a groove in the pin to take a sprung wiper, both of which will be a bit of a pain. Link to post Share on other sites More sharing options...
Karhedron Posted July 31, 2014 Share Posted July 31, 2014 I used to use railzip which both improved conduction and reduced oxidation. I don't use it on track these days because of adhesion problems but it might fit your needs. Link to post Share on other sites More sharing options...
Chris_Walsh Posted July 31, 2014 Share Posted July 31, 2014 A contact in the USA recommends Atlas Conducta-lube for wheel pickups but I cannot find a UK supplier. Does anyone have experience of this oil? Link to post Share on other sites More sharing options...
smokebox Posted July 31, 2014 Share Posted July 31, 2014 I wouldn't use a ball bearing due to the small contact area. A carbon brush or a phosphor bronze wiper may work better. Link to post Share on other sites More sharing options...
peter220950 Posted July 31, 2014 Author Share Posted July 31, 2014 I wouldn't use a ball bearing due to the small contact area. A carbon brush or a phosphor bronze wiper may work better. The ball bearing which runs on the PCB is working fine, as it's got a spring keeping it in constant contact, I thought that a suitably sized one in the bottom of the tube might work, as there is considerable weight bearing down on it, however my preference is for either a grease solution or to put a wiper in a slot in the side of the peg. Link to post Share on other sites More sharing options...
smokebox Posted August 1, 2014 Share Posted August 1, 2014 The ball bearing which runs on the PCB is working fine, as it's got a spring keeping it in constant contact, I thought that a suitably sized one in the bottom of the tube might work, as there is considerable weight bearing down on it, however my preference is for either a grease solution or to put a wiper in a slot in the side of the peg. Whoops! completly misread your original post. You could try rubbing a pencil on some fine wet and dry paper and put the fine dust in the "cup" of the dowel joint assembly. Link to post Share on other sites More sharing options...
Crosland Posted August 1, 2014 Share Posted August 1, 2014 If the ball bearing and pcb works well enough then make two such, as concentric rings, rather than relying on the dowel. Andrew Link to post Share on other sites More sharing options...
DCB Posted August 5, 2014 Share Posted August 5, 2014 It sounds like the basic concept of DCC sound on a turntable is flawed as the turntable will reverse polarity as it turns so at some stage there will have to be a dead period as the loco turns. Maybe someone could come up with a fancy circuit which modulates, the DCC to seamlessly change "Polarity," by doing 45.5 cycles, or 50,5 in one second possibly battery powered? Just a thought. Link to post Share on other sites More sharing options...
RMweb Gold SHMD Posted August 6, 2014 RMweb Gold Share Posted August 6, 2014 It sounds like the basic concept of DCC sound on a turntable is flawed as the turntable will reverse polarity as it turns so at some stage there will have to be a dead period as the loco turns. Maybe someone could come up with a fancy circuit which modulates, the DCC to seamlessly change "Polarity," by doing 45.5 cycles, or 50,5 in one second possibly battery powered? Just a thought. I thought they had - it's called a "Frog Juicer"! DCC changes polarity thousands of times a second anyway. It's its frequency. Changing the polarity, of the DCC bit stream, in 'mid message' would just look like a bit error and would (should) be ignored. If the sound decoders were confused by 'changing polarity' then Live Frogs, Reverse Loops, etc would also 'Restart' the sound. So reversing the signal as the Turntable 'swaps around' will also not cause a problem. (If using continuous rings as the OP has.) Kev. Link to post Share on other sites More sharing options...
Chris_Walsh Posted August 6, 2014 Share Posted August 6, 2014 It sounds like the basic concept of DCC sound on a turntable is flawed as the turntable will reverse polarity as it turns so at some stage there will have to be a dead period as the loco turns. Maybe someone could come up with a fancy circuit which modulates, the DCC to seamlessly change "Polarity," by doing 45.5 cycles, or 50,5 in one second possibly battery powered? Just a thought. This is a bit off topic but, if you are concerned about losing the DCC sound whilst the loco is on the turntable, you could feed the turntable track through a frog juicer. This would switch polarity as the table turns in the same way that it switches polarity of the frog on points. Link to post Share on other sites More sharing options...
Crosland Posted August 6, 2014 Share Posted August 6, 2014 It sounds like the basic concept of DCC sound on a turntable is flawed as the turntable will reverse polarity as it turns so at some stage there will have to be a dead period as the loco turns. Maybe someone could come up with a fancy circuit which modulates, the DCC to seamlessly change "Polarity," by doing 45.5 cycles, or 50,5 in one second possibly battery powered? Just a thought. Those who know about DCC are way ahead of you Andrew Link to post Share on other sites More sharing options...
peter220950 Posted August 6, 2014 Author Share Posted August 6, 2014 Many thanks to all for you assistance and suggestions, The turntable is actually fed through a separate booster which carries out the same function as a juicer, and seems to work fine, though I haven't yet tried it with a sound equipped loco. The problem was one of intermittent contact at one point, which may be down to a bit of fettling of the turntable, this effectively switched off the power if the centre bearing happened to break contact. As it was in a cup I thought something like a grease would ease the problem, an oil would just create a bit of a mess every time the layout was moved. Now that I am in a 'testing' mode, with the guts of the layout completed, I can investigate further whether I can sort it with a conductive lubricant, a wiper on the centre pin, or a second ball bearing roller, as suggested, though I was hoping to keep the second bearing to index the entry points. Link to post Share on other sites More sharing options...
Crosland Posted August 6, 2014 Share Posted August 6, 2014 If the sound decoders were confused by 'changing polarity' then Live Frogs, Reverse Loops, etc would also 'Restart' the sound. So reversing the signal as the Turntable 'swaps around' will also not cause a problem. (If using continuous rings as the OP has.) Not quite the same issue. The problem with a traditional turntable, with a commutator ring to reverse polarity, is that the gaps in the commutator ring cause the DCC signal to be interrupted, causing loss of power. This will cause sound decoders to go silent and then possibly go through the restart sequence (e,g, starting up the engine in a diesel) when power is restored. Electronic auto-reversers (of which the frog juicer is one example) reverse the polarity in an instant, unnoticed by the decoder, with no loss of power. Andrew Link to post Share on other sites More sharing options...
RMweb Gold SHMD Posted August 6, 2014 RMweb Gold Share Posted August 6, 2014 Instead of stating "changing polarity" maybe I should have wrote " as the wheels first come in contact with a reverse polarity rail"! Getting back to the original post from Peter, the brass pivot is that facing down and into a brass cup? Is the brass cup sealed? If so then you could use Mercury. Although some caution on handling and layout storage would be needed. Kev. Link to post Share on other sites More sharing options...
peter220950 Posted August 6, 2014 Author Share Posted August 6, 2014 Instead of stating "changing polarity" maybe I should have wrote " as the wheels first come in contact with a reverse polarity rail"! Getting back to the original post from Peter, the brass pivot is that facing down and into a brass cup? Is the brass cup sealed? If so then you could use Mercury. Although some caution on handling and layout storage would be needed. Kev. Kev, Many thanks for that, yes it's sealed and Mercury is the ideal thing apart from it's toxicity, and having to put it into and take it out of the pivot cup, hence my 'ideal' of a grease of some sort, there is also a possibility that if I lift the cup, or lower the pivot pin the problem will be resolved. At present contact seems to be through the side of the pin, and as it's a smaller diameter than the cup, it sometimes drops out of contact. As I have said before, I may have to resort to some sort of a sprung wiper on the pin, I'm only just at the stage where I can start serious testing so it's down to a bit of experimentation. Link to post Share on other sites More sharing options...
RMweb Gold SHMD Posted August 6, 2014 RMweb Gold Share Posted August 6, 2014 Another daft thought - tin foil. It will be no good where the load/weight is but how about loosely wrapped around the mid section of the Pin. Just keep it away from the 'rings'. It's cheap and may prove a point before becoming unreliable. Kev. (Also against Mercury is that it had a tendency to 'dissolve' other metals!) Link to post Share on other sites More sharing options...
Doughnut Posted August 18, 2014 Share Posted August 18, 2014 Try a spot of Vaseline. I know it's conductive. Dave Link to post Share on other sites More sharing options...
peter220950 Posted August 18, 2014 Author Share Posted August 18, 2014 Really! - if so it's just the ideal viscosity, I'll give it a whirl tomorrow many thanks. - I won't ask how you found out. Link to post Share on other sites More sharing options...
RMweb Gold Dagworth Posted August 18, 2014 RMweb Gold Share Posted August 18, 2014 I'd use graphite powder. Someone earlier suggested using a pencil lead rubbed over wet-and-dry or similar which would be much the same except pencil lead also contains clay as well as graphite, but pure graphite powder is not hard to get, it used to be sold for lubricating locks, Edit: Get thee to thy local decent model shop and get some of this http://www.anticsonline.co.uk/1674_1_2507979.html Andi Link to post Share on other sites More sharing options...
34theletterbetweenB&D Posted August 19, 2014 Share Posted August 19, 2014 Try a spot of Vaseline. I know it's conductive... Not according to the ohmmeter. What it does is protect the contact surfaces from oxidation, and thereby the contacts more readily make good metal to metal contact. Link to post Share on other sites More sharing options...
Chris_Walsh Posted August 20, 2014 Share Posted August 20, 2014 ... or you could try Electrolube HCG - highly conductive grease.I smeared a very small spot on the pickups of one of my locos and it worked a treat Link to post Share on other sites More sharing options...
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