Alan P

Hi Ian As Andy states its a nice start, probably better than my first attempt. My experience is that if you mix fibres that is what you get on the layout, a mixture that appears to lack texture and and has an overall similarity that lacks variations with a definate colour seperation, if you understand my meaning. Having done something like 46 ft on Bob's Fence Houses layout if you look at some of the pictures it will perhaps become more clearer. I know you have seen it in the flesh because you have been on an adjacent stand behind us on a number of exhibitions. My technique is to set your base colour for the overall area working in a small area not too far from the earth pin and with minimum uniform clearance between the mesh grill and the ground. This gives the best upstand as if these distances become too great the strength of the electrostatic field falls away dramatically, I believe as the square of the distance. I have then added different colours or different lengths by adding a second coat as a dusting in selected areas, perhaps even using a seperate different colour to add gradients or blend areas together such as where you go from burnt grass to say a shady area which does not get as much sun. This gives the more definate areas of colour that you have seen. Finally you may want sprinkle some coloured foam particles to add texture. Regarding adhesives I just used 50% diluted PVA for the base coat and in some ares we ended up just using the coloured base paint that went over the plaster skim. To add the second and subsequent dressings I used Firm Hold Hairspray from Poundland. (Quite few cans in the case of FH but I enjoyed the experience). As this is flammable you have to be certain that you are not going to get a spark discharge if you get too near the earth pin. Try a sample outside first to be sure unless you know it does not go off with a loud crack if you get too near or catch the earth pin. My first applicator was home made with an open tea strainer and used to go off with a frightening noise if this happened and as it retained a charge you got one hell of a shock if you touched the mesh when refilling, not serious as there was minimal current but about 1000V was enough to cause you to throw it up in the air involuntary. ( This is the easiest way to convert from what looks like a pool table to a desert in one easy action.) This was never used with flammable adhesives. The second one also based on a fly swat but with a modified circuit so that the charge was not retained and essentially only present when the button was pressed. It was easy to add some burnt grass consistently. In narrow areas such as betweeen the edge of the track and wooded areas or fields where burnt grass changed to normal green I added a paper mask inside the container with a slot cut in it so I could treat a narrow area alongside the track without applying it to an area the full width of the container which contained the mesh inside a plastic housing. Finally after all was set I used to give it a final blow over with hair spray just to ensure evrything was firmly anchored and not likely to work loose in transit. Bit of a long description but I hope you find it useful. We are at the DEMU exhibition at Burton on Trent on 30 May in a non steam format if you fancy a trip to the Brewery Heritage Centre so you can always see the results there and decide for yourself. Regards Alan

Hi Andy That clarifies it nicely thanks. Neat way of doing it cutting a muff, I never thought of that, but it should be quiet. It was those bits of plasticard that threw me as I could not make it out. Interesting, the past discussion on individual wheels not in contact. I have just had the same problem on a Lambton Cab Austerity I built for Fence Houses. ( In mag shortly). I had assumed the wheels were alright and cannot remember now if I did check diameters. It is likely I did and I think I just used a digital caliper as accuracy is a problem with the radius. It was only a small difference but was noted after I removed the flywheel to make the motor worm combination removable. This altered the balance and the centre pair were no longer giving good contact. I ended up increasing the clearance in the bearing and increasing spring tension. Thanks Alan

Hi Andy. Interested to find out your means of mounting motor at drive end. Seems a distance from gearbox with short motor shaft? Have you used a long extension shaft or fitted some form of coupling in there, possibly so the worm is not producing end thrust on the motor? Regards Alan

David Thanks for forwarding your experience. With your reply and Tim's it seems that theory does translate into practice in this case. By what you say I have a good idea of what you have done and mine would be the forward motor case. I am unable to get to Nottingham but hope to be able to get to the NEAG meeting in the afternoon. If you have it with you maybe I could have a look then as you suggest. Thanks Alan

Hello Tim I agree too many bearings in one line is bad and is one reson for my interest. You have answered my query fully. Thanks Alan

Thanks Tim. I saw the earlier pictures in this forum where the complete motor, worm shaft and worm come out as one unit which is a sound principle. This is the type I am hoping to try rather than the seperate motor that Olly guided me to. I have four J94's, actually one J94 and three Hunslet Austerity industrials built for the Fence Houses layout, all chipped. On has been running over three years using Neals wheels and three more were built quickly as spares for Glasgow show. Of these one has the Assn conversion chassis we are talking about with motor at the front and a flywheel on the rear of the gearbox leaving the cab clear. The other two are now having the full replacement Assn chassis built and currently being detailed. So this brings us to the question: The standard chassis has the gearbox hung off the left frame by means of a front and rear support frame each holding a bearing for the worm shaft. Your idea of removing the front bearing in my case so the entire motor worm unit is easily removed is good, with the motor supported at the outer end. The question was this satisfactory in practice (before i cut the etch)? Only using one gearbox worm bearing support makes the gearbox less rigid. I am trying to find out your experience as I know several people who with two bearings (not J94) have had the gearbox flex and have had to solder an insulated pcb support across to the opposite frame to maintain rigidity and gear mesh. Hope you can advise. Thanks Alan

Hello Some time back Tim V built the J94 conversion chassis with a removable motor and worm. This seems a good idea I am interested in this as I did not like the idea of a captive motor and worm that puts extra extra pressure on the box during assembly. How did this work out in practice? Was the single bearing gearbox rigid enough to maintain adequate contact between the gears or did additional strengthening have to be added? Alan

Cannot see any insulation gaps in the pcb spacers, unusual for you. Suggest it is easier to cut these in with a scrawcer before soldering in place. A

Hi Rich Very similar to a design put forward by a P4 member about 35 years ago but more sophisticated. I did something similar at that time which was entirely below the baseboard with the two tubes projecting through two slots. The slots were covered by a layer of paper with smaller slots to stop any ballast jamming the mechanism. The cross bar into which the tubes were inserted in drilled holes was a piece of hardwood something like 3/16" square. This slid in some plastic troughing very popular for thin (1/8")sliding cupboard doors at that time. The trough was shaped like a letter 'E' with two troughs side by side. It was mounted open side to the baseboard withe the crossbar in one slot and fixing screws through the other. Very simple but effective it was offered up over the two dropper wires from the point blades. This was on some 2FS trackwork. It was possible to fine adjust by bending the tubes slightly where they passed through the baseboard to allow for any slack in the tubes if necessary. The only problem that could have happened was the risk of point blades lifting up when cleaning but it never occured. I always wiped from the frog direction when cleaning. A house move meant the layout was scrapped before it got to exhibition stage, but It was always at the back of my mind that any stranger cleaning track at an exhibition may wipe the other way and lift or crunch a point blade. Nevertheless it was completely succesfull but this is something to bear in mind. Its also a simple way for anyone who does not have a milling machine.

We should not lose sight of the fact that all 2mm Association driving wheels are conductive to avoid having to use pickups, leading to better running. Whilst wheels with plastic centres will be suitable for converting commercial steam locos all metal wheels are a better bet when scratchbuilding. I assume FUD is a non conducting plastic but I believe some metal powders can be 3D printed which may be suitably conductive. Many years back we did have some plastic centred wheels in the Association and I believe Geoff Jones had a hand in these. These wheels had a wire down one of the spokes to provide conductivety between the tyre and axle. A few members however experienced these overheating and causing spokes to melt under short circuit conditions. Wheels of this type could be now more vulnerable with the widespread use of DCC where with the extra current available under fault conditions failure could be more common. Its really a case of horses for courses. Some people poo poo the idea of things melting but it is a fact. It does not matter if it welding or melting or acting as a fuse it is basically the same process, metal melting. I have seem two instances on F H of the drive shaft between loco and tender acting like a fuse and melting when a loco short occured but was not a full short cicuit with a resistance low enough to trip the DCC power supply. Both were higher resistance shorts with power maintained for a definate time period..